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GMC Data Report No. 344
Investigations of some mineralogical, petrological, geochemical, and geological relationships at the Arctic Chief (west) locality, Whitehorse Copper Belt, Yukon Territory, Canada Received August 2007 Total of 117 pages in report Alaska Geologic Materials Center Data Report No. 344 INVESTIGATIONS OF SOME. MINERALOGICAL, PETROLOGICAL, GEOCHEMICAL; AND GEOLOGICAL RELATIONSHIPS AT THE ARCTIC CHIEF (WEST) LOCALITY, WHITEHORSE COPPER BELT, YUKON TERRITORY, CANADA Thomas C. Mowatt (1) June C. Mowatt (2) June 6, 2007 (1) Geologist, and Senior Associate, On-Line Exploration Services Inc., Anchorage, Alaska; c/o Post Office Box 1438, Haines, Alaska 99827 USA (2) Geologist (Deceased, 1992) GMC DATA REPORT 3 ~ 4 Page 1/117 PREFACE Due. to convergence of circumstances (time/age, space/distance, funds, "world affairs"), this report has been prepared solely by the first author. For the same reasons it has been neither edited nor reviewed independently. Nor. has S. M. Aleksandrov had the opportunity to do so either. Written comments by Dr. .Aleksandrov presented herein are. set within quotation marks. Though of course these are not necessarily "attributable", strictly speaking, given the ever-present °context", language problems, etc. in such matters, as well as the overall circumstances attendant to working across-the-miles". Including preparation of the present report. However, his recent paper °Gold Behavior during Endogene and Supergene Alterations of Sulfides in Magnesian Skarns" (published in Geochemistry International, volume 45, number 2, pages 152-169, 2007) affords direct access to some of his views as related to magnesian skarns, and our investigations of the Arctic Chief locality. The responsibility for the contents of the present paper lies solely with the first author. Including, in particular, for various °interpretations", etc., based on previous communications with Aleksandrov. The first author may be contacted at the Haines, Alaska mailing address given above. GMC DATA REPORT 3 4.4 Page 2/117 ABSTRACT Investigations of certain geological aspects of the Whitehorse Copper Belt, Yukon .Territory, Canada were initially pursued during 1980-1982, and subsequently continued, after a hiatus of some twenty-two years, during 2004-2007. Principal ultimate concerns were with regard to petrogenesis and associated mineralization. The initial work resulted in the (then) first-known recognition, and confirmation, of the "magnesian-skarn" character of the Arctic Chief (west) locality. Analytical procedures featured stereo-microscopic sample examination, petrographic as well as ore microscopy, x-ray diffraction, and x-ray emission (fluorescence) spectrometry. At this locality a key feature, also initially recognized and confirmed at that time, was. the occurrence of "periclase (brucite) marbles", with "classic" examples of the type present. Other significant features at the Arctic Chief characteristic of magnesian skarns -- initially identified as such -- included rocks of "calciphyre" character, the presence of a number of other magnesian minerals (in addition to pyroxene[s]) -- including forsterite, serpentine, spinet, phlogopite, Mg-chlorite, talc, clinohumite(?) --, and. the presence of typical "rhythmic banding", or its vestiges, in rocks, as well as in "ores". In addition, the (quite) speculative presence of Mg-Fe borate minerals of the ludwigite-vonsenite series was indicated, though this remained unconfirmed at that time. Unfortunately, this initial work remained unreported, formally, at the time. The subsequent work (2004-2007) provided an expanded sample base. Some one hundred selected specimens were sent to S. M. Aleksandrov at the Vernadsky Institute, Russia, for use in his. own research. His subsequent definitive work on them confirming, as well as significantly extending, our previous findings. Providing confirmatory evidence for the formation of the borate mineral magnesian-ludwigite (pseudomorphously replaced by magnetite) at the Arctic Chief . As discussed in a portion of a paper by Aleksandrov in Geochemistry International, (2007). The Arctic Chief (west) locality is demonstrably an example of a "magnesian-skarn". Additionally, our work, collectively, has shown that rt features a version of "primitive-type zoning", formed under conditions of the "hypabyssal periclase facies", as considered in the context of the model of skarn-formation developed and refined by Aleksandrov and co-workers. This approach merits consideration regarding the nature and origin(s) of "skarns", particularly with regard to those associated with "host" rocks of "dolomite/ dolomitic/ magnesium-rich" character. It offers a conceptual, as well as substantively based, framework of theoretical background, fundamental knowledge, and experimental work. As well, it affords ample evidence, from a wealth of experience and analytical work, supportive of the validity of this approach to the genesis of skarns. Including our work on the Arctic Chief. Appreciation, and utilization, of this model ought to be an essential aspect of investigations intended to further the understanding of such geological occurrences. In turn, potentially yielding insights of "more practical" value in the exploration for, evaluation of, and production of mineral resources from deposits related to magnesian skarns. Such as has been the case in many areas, worldwide (cf. Aleksandrov: 1998, and numerous other publications). Our 2004-2007 investigation also resulted in the recognition of some interesting occurrences of molybdenite, and other mineralization, near the Arctic Chief. Implications of any/all of the above points, locally, elsewhere in the Whitehorse Copper Belt and environs, as well as elsewhere regionally, remain to be evaluated. 1 GMC DATA REPORT 3 4 4 Page 3/117 PART 1: Introduction, summary of results, interpretations. INTRODUCTION: A study of certain aspects of the Arctic Chief locality/ore deposit, in the "Whitehorse Gopper Belt° (cf. Watson, 1984; Tenney, 1980; Morrison,1976, 1981; Heon, 2004; Meinert, 1986; Wheeler, 1961; Kindle, 1964; Grabher, 1974; Dawson and Kirkham, 1996; Aleksandrov, 2007; etc.), was initiated by the first. author ("TCM") and the second author {"JCM°) in 1980 (cf. Mowatt and Mowatt, 1982). This work was done while. TCM was employed as Supervisory Geologist by the Alaska Field. Operations Center, United States Bureau of Mines ("USBM°), Douglas (Juneau), Alaska. The intent was to attempt to add to the understanding of the nature of this "skarn-type" ore deposit, by investigating certain aspects of the mineralogy, petrology, geochemistry and geological relationships. Of particular interest were a number of key features of deposits of this "skarn-type° elsewhere, as recognized and elucidated over the course of a number of years by the extensive work of S. M. Aleksandrov ("SMA°) and colleagues at the V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian (formerly U.S.S.R.) Academy of Sciences, Moscow. TCM had the privilege of working with Dr. Aleksandrov, while serving as .the tatter's professional host in Alaska on his two "scientific/cultural exchange programs visits to the U.S.A. (1973, 1979). These visits were made possible, jointly, by the Academies of Sciences of the U.S.S.R. and of the U.S.A. Thus began a coNegial relationship which has continued since. 1973 to the present time. Working together in the field (Seward Peninsula and elsewhere in Alaska), laboratory and office proved most informative, and quite valuable. Hence the subsequent initiation of the USBM project in 1980. In 1980 knowlege and/or appreciation of the significance of the work on contact metamorphic/ metasomatic "skarns° and related mineralization/ore deposits by SMA and his associates was not notably widespread elsewhere. Thus, implications of this work with regard to understanding of the formation of skarns and related contact metamorphic/metasomatic mineral deposits were not widely appreciated outside the U.S.S.R., and other places where geologists from the U.S.S.R. had .worked. At the Arctic Chief (west) locality, fundamentally the principal concern of the study initiated in 1980 was with regard to the nature of the skarns) present; ie. whether this was an example of a "magnesian skarn" (per the usage of SMA) situation/occurrence. If so, as preliminary impressions obtained by TCM and JCM had suggested, what implications might this have with regard to the Arctic Chief ore deposit, other deposits/localities/occurrences of mineralization in the Whitehorse Copper Belt area, and perhaps regionally as well? . These considerations were addressed in the context of the concepts (featuring an emphasis on metasomatic aspects) developed as the result of the work of SMA and associates, featuring extensive and effective applications elsewhere in the .world, in terms of mineral resources: exploration, development, production, and uses -- some .rather innovative. One of the more noteworthy aspects of their work was the elucidation of previously unrecognized. types of deposits of boron, and of tin. This also resulted in some innovative exploration, production and utilization methods. Raising reasonable questions as to possible implications/applications. elsewhere (cf. Mowatt, 1984; Mowatt and Jansons, 1985). 2 ~i~NIG i1~~~~~ i~~{~~k~T ~ d 4 Page 4/117 Cn the basis of the information and insights obtained as the result of working with SMA, the skarns of the Whitehorse Copper Belt were of obvious interest, in terms of the geology per se, as well as with. regard to relationships to mineral resources; Known as well as potential At that time, the definition(s), .the recognition, of "magnesian" skarns as such, the geological significance of their presence -- or .absence --, and implications as to related mineralization, were topics remaining, in general, somewhat ill-defined.."Geo-esoterica" whose .relevance, other than "academically", was yet to be determined. At the time. (other than in the U.S.S.R., and a few other places) this was not a topic of widespread apparent interest in geological science. A skarn was, essentially, simply a skarn..... To a certain extent, with some notable exceptions, in many respects this state of affairs had changed relatively little in the interim between 1980 and 2004, as it turned out. Though by 2004, the technical literature (and TCM's personal library, thanks to SMA) contained even more numerous contributions on the subject ey SMA, and associates, including books. Cf. the REFERENCES. section of this report; especially Aleksandrov, 1998. 2007. The 1998 reference is "the book" on the subject:. "Geochemistry of Skarn and Ore. Formation in Dolomites". The 2007 paper, published in Geochemistry international, though with a broader theme, offers a concise yet informative summary of Aleksandrov's approach!"mode!", as well as featuring a discussion of the results of our work on the Arctic Chief by way of an example. STU®IES: Initially, field .investigation and sampling of bedrock outcrop/pit wall exposures, associated "rubble-crop", and related "float" materials were carried out by TCM and JCM at the Arctic Chief locality in 1980-1981. This was done in the context of consideration of various. key features, and relationships, of minerals and rock types, and their "position" (geological, geochemical, temporal andtor spatial} as developed and elucidated by SMA and co-workers. Subsequent analyses of these materials were carried out at TCM's laboratory at the Alaska Field Operations Center, USBM, facility in Douglas (Juneau), Alaska. Analytical capabilities featured stereo- and petrographic microscopy (#ransmitted and reflected light), x-ray diffraction ("XD"), x-ray emission (fluorescence) spectrometry ("XRF"), and fire-assay. COtNMENTS QN F#ESlJL.TS FR®M THE 1980-1982 STtJ®Y: Gleaned,. insofar as feasible, from an incomplete collection of various items exhumed in 2004 from personal materials long stored-away. (See remarks below regarding the regrettable ".affair of the missing/lost report".) Featuring battered and tattered copies (TCM, JCM) of field notes, sketch maps, "rough-drafts", the odd scrap of paper resurrected from an o!d book, etc.; also some long-retained "paperweight"-type pieces of "choice" specimens; other sundry oddiments. Supplemented by thoughts recaptured, variously, from personal (TCM} memory. .Perhaps first and foremost, the matter of those splendid white-grey rocks, gleaming and sparkling in the Yukon summer sunshine. "Marble(s), apparently. Indeed, as it turned out. In fact the not-unanticipated "perictase (brucite} marble". This. a key to the magnesian- skarn character of these rocks --; of the nature of this depositfoccurrencellocality. Per SMA: publications, personal communications, and remarks elsewhere in the present report; as well. as, now, his 2007 paper. The formation o€ the mineral perictase in these rocks of course an aspect of decided petrogenetic significance (cf. Turner, 1968; .Winkler, 1979; Aleksandrov, 1998. Among numerous others, over the years....... }. 3 GMC DATA REPORT 3 4 4 Page 5/117 This initial recognition at the Arctic Chief was based principally upon hand specimen examination in the field: "marbles"; with brucite pseudomorphinglreplacing periclase -- as occasionally especially evident on weathered surfaces of some of the rocks. Bringing certain recollections (TCM) of 1873, working in the field on the western Seward Peninsula, Alaska. Quoting SMA: (( [This} "Is periclase marmot. If you want to see periclase marmot, here it is. If you do notwartt to see periclase marmot. WeIL........ But, i s periclase marmor.° While displaying a chunk of light grey rock, with a certain knowledgeable flourish. lh'hile our somewhat "politicized" colleague of that .day. shrugged skeptically and wandered -off.}} Memories of that foregoing double-bracketed bit of (rather short-sighted) "geo(political)- byplay" remaining with me ever since. From a personal first-hand introduction ~- education -- provided by SMA, in 1973, on an upper flank of Brooks Mountain, in the Lost. River region. Followed, some years later, by recognition of similar features, in the field at the Arctic Chief. Duly followed by laboratory confirmation under the microscope(s). Further confirmed via x-ray diffraction .and x-.ray emission (fluorescence) analyses of numerous specimens. Mineralogy recognized featuring calcite, +/- dolomite; brucite (pseudomorphous after periclase; not infrequently with associated relict periclase present as well); minorltrace amounts (varying among specimens) of spinet, forsterite, magnetite, phlogopite, serpentine, talc, "hydrotalcite", (+{- ?). Featuring crystalline "marble" textures, with traces of variously-well-developedf-vague, not infrequently "patchy", mineral .and textural banding in places. Many truly exemplary -- "classic/textbook" -- examples of periclase (brucite) marbles were examined in specimens collected firom this locality. As SMA was to observe, even more years later, the Arctic Chief indeed features "splendid" periclase (brucite) marbles. While there were also other variations on the theme of "carbonate" rocks, those we termed "calciphyres" in the field. Confirmed as such in the laboratory. In addition to predominant calcite, characterization of other minerals -- microscopically, supplemented by ?CD and ~RF -- in these specimens revealed, variously, forsterite, pyroxene, magnetite, spines, serpentine, phlogopite, chlorite, clinohumite (?). With relationships, textures characteristic of "calciphyres". Banding, of (varying) "rhythmic" character likely attesting to metasomatic activity, manifested. A!I of these factors indicative of the probable "magnesian skarn" nature. of this locality. As well as consistent with the concepts developed by SMA and colleagues. Also .recognition of similar ("rhythmic") banding in "ore" specimens. Featuring magnetite, +I- sulphides, (+/-), and associated "bands"!"layers" of forsteritelserpentinel phlogopite, +/-?. Further attesting to the "magnesian skarn" character of this deposit. As well as presenting significant evidence as to the genesis of these "ores". Per the SMA. "-nodei". Also present, in some marbles and calciphyres, some rather small "needle-like!-shaped" black crystals. Possibly the Mg-Fe-borate mineral "ludwigite"(?). Such morphology being. a characteristic feature of ludwigite (cf. Ramdohr, Uytenbogaardt .and Burke; Afeksandrov). In our specimens, these crystals unfortunately too few, and too small, for informative XD analysis.. X-ray emission (fluorescence} spectrometry of bulk sample and partial concentrate materials (the samples proving not amenable to effective concentration of these "needles", for ?CD or XRF analysis) indicated relatively high iron contents. Suggesting that the black mineral could be magnetite. Which is not uncommon -- rather characteristic, actually -- as a pseudomorphic replacement of Mg-Fe-borates. As indicated in the literature by Ramdahr; Uytenbogaardt and Burke; Aleksandrov. Alf affording the speculative possibility of original 4 GMC DATA REPORT 3 4 4 Page 6/117 needle-shaped crystals of Mg-Fe-borate having formed as the mineral "ludwigiten in these rocks. if so, this would provide additional evidence supportive of the magnesian skarn nature of the Arctic Chief locality. As well as providing further insight into .other petrogenetie and geochemical particulars of its character. Similarities to the Lost River, Brooks Mountain, .Tin Creek, .etc.. areas (western Seward Peninsula, Alaska) were striking. Enhanced by samples and photographs from other localities furnished by SMA during the course of our ongoing association since 1973. Thus, in summary: The "rhythmic-banding".......... in rocks, and in ores. The mineraiogies........ The plethora of miner~togic, petrologic, geochemical indications as to the apparent "magnesian skarnn character of the Arctic Chief.......: As gleaned from the "collected v~rorks", on-going correspondence, and first-hand personal experiences working with SMA....... Further including, as a matter of "positions (geologically, spatially, as observed in the field}, the apparent relationships (displayed at various scales, from hand specimen up to deposit dimensions} of: igneous rocks, generally of granodioritic-divritic character; "(calcic-}skarn" materials --- pyroxene, garnet, +/- ; relative to the principal "ore" occurrences of magnetite and other ore-minerals; the (generally} more "diets!" calciphyres; relative to the further-distally-positioned marbles. Manifesting the sequence of geochemical events and geological relationships recognized and elucidated by SMA and co-workers; the "position(s}"; and the "processes° attendant thereto. Summary of the "evidence°: Periclase (brucite} .marbles. calciphyres, with predominant calcite, as well as, variously, forsterite, pyroxene, clinohumite (?}, magnetite, chlorite, phlogopite, serpentine, spine!, +/- etc. Possible (?} pseudornorphs of magnetite after "borates~; ie. ludwigite (?). Ores of magnetite-phlogopite/serpentine/forsterite, +f- sulphides. Rhythmic banding in rocks, and in ores. Relationships (and nature) of successive "magmatic" ---> "postmagmatic" eventslmineralsfetc. {le. "prograde", and "retrograde°, respectively.} "Zonalityn/"position, and the character thereof. Spatially, geologically and geochemically. Representing "recognition", in 1981, of the Arctic Chief locality as a "magnesian skarn° accurrence/-related deposit. With attendant implications as to geological, petrological, geochemical, and mineral resources .considerations. The principal geochemical determinant for the presence, or absence, of the required magnesium for magnesian skarn formation being the nature of the original "precursorial" host rocks intruded b}~ the related igneous materials}. A U. S. Bureau of Mines Open-File Report was prepared dealing with the results ofi this198t)- 82 work. A "final-draft" copy of this report (cf. Mowatt and Mowatt,1982}, together with fifes, rock and mineral samples, petrographic specimens, and related analytical data, .were left with the Juneau office of the Alaska Field Operations Center, upon TCM's resignation from. the USBM in mid-1982. Unfortunately this report, as welt. as the related sample materials, files, and analytical data, subsequently "were lost/went missingn. Perhaps similarly disappearing completely, upon abolishment of the U. S. Bureau of cE4ines by the U. S. Congress, ca. 1995. 5 GMC DATA REPORT 3 4 4 Page ~/11~ CONTINUING STUDIES: Results from the ongoing work by SMA and his col{eagues continued to appear in the technical literature. Summarized, in particular, by the publication of Aleksandrov's comprehensive book "Geochemistry of Skarn and.Ore Formation in Dolomites". Initially appearing in 1990, in aRussian-language version; an :updated version was published, in English, in .1998. This monograph (the "[SMA, 1998j" book) providing a valuable, as well as timely, integration and summarization by a respected investigator. An acknowledged. authority, with extensive experience (of fundamental research, as well as "applied", .nature) with this complex subject. I n combination .with continuing correspondence, exchange of books, .papers, data, samples, photos, ideas, etc. with SMA over the years, the "synthesis° afforded by this particular book spurred TCM to revisit the Arctic Chief locality in .2004, upon his retirement and relocatiori to .Haines, Alaska. Though admittedly a certain Level of lingering professional .frustration, as well as personal "annoyance", regarding the unfortunate "disappearance" of the previous efforts of 1980-1982 might well have provided an additional motivating factor. Further strong incentive was the opportunity afforded to work with SMA, "across-the- miles°, providing him information, samples, literature, etc. from yet another locality, to add to the many others he'd already studied. The subsequent work in Canada and the USA was carried out at the personal expense of TCM. Sort of an ad hoc "post-doc" opportunity, as it were; though a rather "low budgets one. As well as an acknowledgement, a "professional courtesy", as it were, to a valued colleague -- and mentor -- of longstanding.' With the view to rexamining this "mined-out" ore deposit, in .hopes of confirming -- or perhaps improving upon -- the information obtained in the earlier "lost" study. -Field sampling was done by TCM during the summers of 2004-2006. As before, samples of bedrock {outcrop, or pit walls), as welt as associated "rubble-crop" and related "float" ~materals were obtained. Taken, insofar as feasible, from the same general areas of the Arctic Chief (west) as had been sampled during the previous work. A substantial collection resulted. All samples were subsequently examined further, in preliminary fashion ("triaged°), by TCM in Haines. Utilizing hammer, chisel, hand lens, acid bottle, and a 30x/60x stereo microscope on rock surfaces (freshly-broken and otherwise). In some select cases, also examining grains-in-oil materials using apersonally-owned petrographic microscope. Deferring to SMA -- the acknowledged authority -- for decisions as to thin-/polished-section petrographic analysis, etc., as he might see fit. In any case, the "low-budget" circumstances. precluding. appreciable petrographic thin-/polished-section preparation and analysis by TCM. Selected "triaged" materials (about one hundred specimens, in all). were then mailed to SMA, at the V. L Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, for examination, evaluation, and further analysis as he deemed appropriate to his own ongoing research. This latter work included hand specimen, petrographic microscope, microprobe analysis, etc.. of representative materials of particular interest Following sections of this Part 1 of the present report deal with results of these examinations, evaluations, analyses; summaries, comments and interpretations. While Part 2 of"this report, the "DATA SUPPLEMENT" addendum, presents additional information: sketch maps showing general locations of sample sites, abstracted field notes, results of 30x/60x stereo- microscope examination of samples, petrographic microscope examination of selected materials as grains-in-oil, analyses and other comments by TCM. 6 6MC DATA REPORT 3 4 4 Page s/11~ COMMENTS {TGM) REGARDING THE PAPER. "Gold Behavior during EndogeniC and Supergene Alteration of Sulfides in Magnesian Skarns" BY S. M. ALEICSANDROV, PUBLISHED IN GEOCHEMISTRY INTERNATIONAL, 2Q07, VOLUME , 45, No. 2, pp. 1 52-y 69: In the context of the present report, first and foremost among comments which might be put forward is the observation that, in portions of Aleksandrov's paper, the. results of our work on the Arctic Chief IocaGty over the years are nicely summarized. Representing the initiat publication of this information in the open literature. !n addition to material from other Sources, his paper. uses the results of our investigations to present the Arctic Chief as one of several mineral deposits selected to exemplify aspects of the broader concerns discussed. The known occurrence of valleriite at this and other nearby. deposits is particularly relevant, given the role of such hydroxisulfide minerals in several. aspects of the geochemistry of gold (as well as platinum-group elements), as discussed in his paper. As evident from its title, the paper overall is of a more general nature. Quoting from the informative Abstract, "The paper presents materials on the genesis of gold deposits of the magnesian-skarn association. ...... The materials presented in the paper characterize the behavior of gold in the endogenic and supergene processes at magnesian skarn deposits." In addition, as essential background information antecedent to dealing with its principal topic, the "introduction", and the immediately following "Genesis and Zoning of Magnesian Skarns", sections of the paper, pages 152-153, offer a valuable and concise summary of magnesian- skarn per se, from the viewpoint of a recognized authority on the subject. to the "Introduction", in the first two paragraphs, besides commenting on the mineral resources aspects of magnesian-skarns, also offering some other rather cogent observations in the process. Observations which, from personal experience, seem quite appropriate. Since they concern themselves with matters of fundamental significance to geological science. In pursuit of increased "sophistication, efficiency", etc., as scientists we continually need to remind ourselves not to do disservice to the "basics" in the process. Lest, among other things, we fail to `let the. rocks speak for themselves", as it were. The "Genesis and Zoning of Magnesian Skarns" section offers a veritable tour-de-farce in one page, nicely summarizing the accrued knowledge, experience, and perspective of many years, many Iocalities(deposits, many rocks, and much thought on a complex subject. Leading 'into the following section by ending as follows: °Sulfide ores, including those with gold, in hypabyssa! skarns are very diverse and are deposited during the postmagmatic stage, selectively replacing compositionally diverse metasomatic zones of the contact aureoles. This can be illustrated by the example of the Arctic Chief Cu-Au deposit, Yukon Territory, Canada........" The next section, "Arctic Chief Skarns and Ore Mineralization", pages 153-156, then proceeds to develop this theme, utilizing information obtained from other sources, principally Tenney (1981), and Meinert {1986), as well as the results of our own studies. Among others, one important point in particular seems worthy of special note here in thlS commentary. On page 154, Aleksandrov .observes: "The magnesian skarns of the Arctic Chief 7 GMC QATA REPORT 3 4~4 Page 9/117 deposit occur not only at contacts with the [main] intrusion but also around injections of diorite melts into dolomites ,(Fig. 2}. The rocks preserve their zoning and inclusions of Mg- ludwigite in the forsterite caiciphyres but contain no magnetite ore mineralization" (associated directly with the. fatter, sm~lterfminor `injections', ie.]. illustrative of this, his Figure 2, on page 156, offers a drawing of a rock specimen This specimen happens to be the one designated "TM-04-10-12-22-B-104" when it was collected in the field at the Arctic Chief on Octoberl2, 2004, at sampling locale "22-B". Described by TCM in his "triage phase of analysis as a "VERY NICE SPECIMEN", among other comments. This specimen was subseguenty sent in its entirety to Aieksandrov. Studied, depicted and discussed; by him. Who also apparently found it a `very. nice specimen'. Collected 'rn the near vicinity of a larger skarnfapophysisflens of tongue-like aspect, featuring zoned igneous and "skarn° materials within carbonate host rocks, with green, blue, +/-, "rusty"-fcopper-staining present. in places along. its margins. This. larger .feature is a rather "gaudy"fspectacular one; well-photographed, 2004 and later. As well as, subsequently, in .2006, collected in detail as samples "TM-06-S-22-2-........". Cf. maps,. descriptions, etc. by TCM in Part 2 of the present report, the "Data Supplementu addendum. Location is at the northern edge/margin of the entrance cut of the Arctic Chief (west) pit, exposed up on the sidefwalt of the cut. In the vicinity of the corefcrest of a tightfoverturned fold in the carbonate host rocks. Below map#3 (ie. TM-04-6-9-3 locality). [For additional information, see the section of the present report, below, entitled FIELD LOCATIONS, INFORMATION, GENERAL REMARKS, (TCM} ON SAMPLES STUDIED BY S. M. ALEKSANDROV. (REFER TO PART 2 OF THIS REPORT, THE "DATA SUPPLEMENT" ADDENDUM, FOR SKETCH MAPS; SELECTED SAMPLE DESCRIPTIONS, OTHER DETAILS).], Comments in earlier fetters, SMA to TCP~A: "ludwigite is in serpentine-bearing .marble TM- [04]-10-12-22-B-104... May be in contact with marbles you can see kotoite Mg3(B03)2? ....° ....... "Yau can see rhythmically-banded textures, that inherit, and in magnetite ores. (The best you can see in TM-04-10-12-22-B-104 --- [the sequence] around diorites' injection in marbles: exchanged ["altered"] diorite--ctinozoasite rim-- pyroxene skarn--banded ludwigite-bearing forsteritic calciphyre--banded periciase (brucite} marble.}~ According to its caption, this Figure 2 illustrates "diorite injection. in dolomite and zoning in magnesian skarns"........... Recognized as such in the field, too. Collected with precisely this intent, this specimen is used as an example -- "in microcosm", as it were -- of the general relationships {"positions"} typical of magnesian skarns, at various scales from hand specimen, as here, through "deposit scale". Per the "model" for the "geochemistry of skam and ore formation in dolomites" as developed and set forth by Aieksandrov and his associates. Providing further illustrative bonuses, as observed, and depicted, this. informative specimen also features "rhythmically banded forsterite caiciphyres"; and "disseminated crystals of magnesialudwigiten. In addition to the other compositional and texture! features characteristic of magnesian skarns so nicely displayed in this one specimen. Collectively, "Letting the rock speak for itself", as it were...... (though an "appreciation, comprehension, understanding, of the language" is, admittedly, important to this......). This Figure, this specimen, the evidence afforded, suppiemen~ed by Aieksandrov's comments, sufficiently informative to merit incorporation in the present report. A "key" item. Thus this Figure 2 and its entire caption are reproduced below: 8 GMC DATA REPORT 3 4 4 Page 10/,117 156 ALEKSANDROV 11 11 11\\~~~~ ~~~~ ~ ~i// ~'~ __-= -~ ~/////1 I II l.lll III /1 i~l)1 i////~i/~/,~ ---_-~~~//~ rlPi #I ~'•tIl i/ r/'/ ~//i /i i%///i//%~ ~'_- =_;/~/ ZO \~±itilllyl~lllill\)1j\1'~'llllj\~~ r~nl//~~~/ Ph /,~~,1111111\\,\\ \;`\.\~\, '11j1 jrgrr L// 1 IIIIILd \~\, \\~\ ~\~..`~,\,411,1 p 111 _ ~i 111,\•1\.)\1; \\`\`i\,~\1'FoCa'r"\\ ~D" ~'~/ 11\ll\\11~~I111i )I'i'LI\\ql~~, Ir,i 111 ``\~ ~ 3% Sir \)\\~\)~~\~\il \\\`\`\\\`'`1\ \\I\\~\~ \ \ ` /r, ~~~ \~•~q 1., 11/,..x.. .~ \ 1 1,• __, \ 3 1,/ ~p11 111!/ //// // 1 / /II l~4#iI ~U\5 ~~/4~/~!1\1`\\ / / u 111 \\F /~ ,~ ~/ , ~ \ \ \~ ~. l1/!///, ///1111/////, l'I~~111\\\`' 1"'#*\~~`_/i%// i\\`.<.__-~ Fig_ 2. Diorite injection in dolomite and zoning in magnesian skams" Arctic Chief deposic(sample of T.C" Mowatt). (1) Diorite replaced by zoisite (Zo); (2) phlogopite-diopside skarn (Ph); (3) diopside skam (Di); (4) rhythmlically banded forsterite calciphyre (FoCa); (5) disseminated crystals of magnesioludwigite (Ld). Magnification 2.5x" s GMC DATA REPORT 3 4 4 Page 11 / 11 ~ The remainder of the Aleksandrov paper deals in some detail with the broader topic of concern, as to gold (+/-PGE), sulfides, and magnesian skarns. Providing much material worthy of further attention, especially the role of °hydroxisulfides" of the valleriite-tochilinite, etc. genre (note esp. p.160, comment rel "brucitization", etc.), with implications of fundamental scientific, as well as "applied", significance. Summarized well in his "Conclusions" section. To our knowledge, .our work, per Aleksandrov's discussion, represents the first such treatment (at least published in the open literature) of the Arctic Chief from this particular viewpoint of the genesis of skarns and related ore formation. As such, it offers a somewhat different perspective than apparently has heretofore been brought to bear on this subject, at this particular locality/deposit, or in the Whitehorse Copper Belt, or in the region. This would seem to be a perspective .meriting more extensive appreciation, consideration, application than previously has been the case. Aleksandrov's comments regarding the Arctic Chief, based on information/data derived from the other sources mentioned above, as well as our. own, demonstrate the apparent applicability, "utility", relevance of this "model" to this particular locality/deposit. As well, in the context of this model, and its demonstrated usefulness elsewhere, suggesting possible implications with regard to skarn and ore formation in this region too. The "SUMMARY AND CONCLUSIONS" section of the present report, below, also offers a bit more ("grinding-of-the-axe"?) commentary on this theme.... With regard to the analytical and interpretive details, Aleksandrov's findings are in agreement with the results, tentative and otherwise, of our initial work carried out in 1980-1982 on the Arctic Chief (see above). Not too surprisingly, of course, given the background of the professional relationships among the investigators. The subsequent work since 2004 confirming those earlier observations,. in general, as well as in most all of the details. As well as, importantly, providing confirmation of the formation of Mg-ludwigite at the Arctic Chief. While adding a valuable increase in the level-of-confidence in the previous analyses and interpretations, with S. M. Aleksandrov the Principal Investigator this time. Including utilization of microprobe and .other capabilities at the V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. Some selected comments, etc. from our 2004-2007 study of the Arctic Chief are presented in the following portion of the present report. These are intended to offer additional perspective, insights, supportive information, some relevant details, etc., in the context of our research. The section immediately below presents some of the general comments, observations, results, interpretations, etc. shared with TCM by SMA, during the course of this investigation. 10 GMC DATA REPORT 3 4 4 Page 12/117 GENERAL ®BSERIIATlOlVS, CGMME[~TS, ETC. ®F S. M. ALEKSA~I®RCVe Selected portions of a letter from SMA to TCM, Sept. 14, 2004: "What ! say about samples? Gf course this is Enagnesian skarn. ! read article [sent by TGM with an earlier fetter] by L. llAeinert about Whitehorse copper belt deposits (1986), that contain its characteristic analytical .data for rock- forrning and ore-rnlnerals and composition of intrusive rock (see all tables in his article). [Bold emphasis by TCM] As first result I think that temperature of skarn formation after dolomites IPi C©ntact with intruded granodiorite melts (content 58.3% Si02) was near 10000 (after F. G. Smith). -The granodiorite is product of assimilation of country rocks by over-heating granitic melts (see my articles from 90's years). The absence in skarns of rnonticellite zone are given possibility to suppose its belonging to hypabyssal periclase fades of dolomite progressive rrzetasomatism in magmatic stage (see fig. 16, 17, .and 18, 24 in my book,1990). its zonaiity is: granodiorite contactflpyroxene skarn with. spinal --- (+/- forsterite skarn) --- forsterite calciphyre --- periclase (brucitized} marble --- host dolomites. A!I early pyroxenes are diopsides (Di > 90 mol%), but alt salites are secondary (postmagmatic new formed} and content Fe-component more as 10 up to 14-20 mol % hedenbergite. Forsterites are high Mg. May be are black magnetite? Diopside + spinal paragenesis on postmagmatic stage transformed in (into] a little Fe-content phlogopite as also forsterite + spine! rocks too. In the same time formed clinohumite after forsterite in calciphyres. (Note:. valleriite in this time of process is absent, it is low temperature mineral C7nly at last stages clinohumite is altered into brucite and rnagnesite; fully losing F, and appearance of sulphides may be doing its reaction with formation of hydroxosulphides.) Near intrusive rocks took place development postmagmatic secondary calcskarns after part pyroxene zone of Mg-skarn rocks with appearance salites, vesuvian?. Mg-amphiboles (actinolites after salite), garnet andradite-grossulare composition and woltastonite near granodiorite (fig. 63 in book}. Mg-spine) is transformed into gahnite. After granodiorite appear garnets of grossulare composition and Fe-bearing epidote as endoskarn minerals in postmagmatica! associations. Sulphide mineralisation is next at the last ore step after secondary calc skarn (and greisen). At low temperature, minerals you can see are brucite (after periclase}, serpentine (after forsterite} and Mg-chlorites (after phiogopite}. The presence of valleriite (in ores at Arctic Chief up to 30% !?, and North Star, see Meinert's article. Also see data of K. Harada, 1973, about Little Chief, Yukon and W. Petruk et al, 1971} .............. The name valleriite is going for honor Swedish mineralogist .Prof. G. Walierius (1683-i 743, see Dana, et al, Sulphides}. 11 AMC DATA REPORT 3 4 '4 Page 13/ 117 About genesis and rote tochilinite-vaileriite. Are common low temperature minerals in all pyrrhotite ar mackinawite basic rocks (Mg-skarns, kimberlite, gabbro, dunites, etc.) and in its are tochilinite or haapalite {as Ni-analog in pentlandite ores). The presence in those rocks of Cu-sulphides is given start for formation valleriites {for example, Chamberlain, J. A., Detabio, R. N., Mackinawite and vaileriite in the Muskox intrusion. Amer. Mineral., 1965,- v. 50, #5-6, 682-695). its formation after Au, Ag, Pt, and Pd-bearing sulphides assume appearance free micron [sizelscale} particles of noble metals in mass of hydroxosulphides. The presence this shirt. [coating] are giving big difficulty for sulphides. flotation in extraction process and evoke loss of Au and Pt. Probable these particles in hydrotherma! and supergene conditions are easily soluble and redeposited on larger metal grains as first steps for growth of nuggets. For Yukon climate is actual the presence of permafrost effect. This is promoted to [facilitates increasing in many times. concentration Au in rest solutions in ice freezing up t0 oversaturation and pass electrolytical reaction with redeposition as "new gold" of intermetal compound {see vaileriite article). New data about sulphides (with Au and Pt) from Mg-skarns of world and vaileriite-tochilinite will be published in Geochemical International in 2004 (#5, see Lebedinoe. Yakutia and others and #9) and 2005 (#3 and oth.) and I will be send its for you." "A few questions from me to you, Tom, if You permit: 1. What are spatial (geographic) correlation lode and placer. Au deposits in Whitehorse belt? 2. Are or not any boron minerals in deposits in the copper belt? 3. [n copies of article that you sent me, are very often data about presence in skarn hematite or specularite, that are very seldom. for Mg-skarns. Probable this is Mg-Fe-boraces: ludwigite or huisite and its magnetite pseudomorphoses? 4. From publications t know about presence Mg-Fe-borates (ludwigite? or huisite?) on Swift River near Seagull batholith (southern Yukon). In contact .zone Thompson, R. M. from Univ. of B. C. (see introduction in Petruk article) and Gower, L. A. have described Mg-Fe-borates in sphalerite ores (American Mineral., 1954, v. 39, #5-6." Selected portions of a letter from SMA to TCM, November 15, 2004: "Ali enclosed materials by D. Tenney and others are fully interesting to me. l am sure, that ore-bearing magnesian skarn may be more widely distributed in western Canada (see article about borates in North America). Of course, it is necessary to remember, that near contact with granitoids calc-skarns minerals can have alteredlrepiaceel Mg- skarns and mask its presence, but magnesian minerals. {forsterite, clinohumite, phlogopite and periciase) are corsstantly present in marbles. [Emphasis by TCM.] 12 GMC DATA REPORT 3 4.4 Page 14/117 Thank you for description to deposits near Arctic Chief in Whitehorse ore belt About moiybdenite: it is one last sulphide on gold skarn localities. I encountered it in phfogopite rocks in Eastern Chukotka, in altered granodiorites in Yakutia, and in pyraxene-garnet- skarns with Bi-sulphides and Au in Hol-ICoI North Korey. Green mica-like minerals in skarns may be cliritonite or phlogopite.» "About .temperatures of initial granitic melts: It in norms! dry granitic melt with 72% SiQ2 (T meth is near 8200 -after F. G. Smith:"Physical Geochemistryn, who is giving data about T melted dry magmatic rocks from gabbro - t 250C up to pegmatite) is a little more for. melting exocontact pyroxene skarn. For it T must be near 12000 (See articles #28, 31, 32, 33 ). [[tn SMA "BIBLIOGRAPHY"/publications list, sent in a recent .letter to TCM. See "REFERENCES section of present report.]]. For assimilation basic host rocks is necessary presence high-heated granitic melt. What are any data? 1 see in Russian, translated the book iielrnut G. F. Winkler, who give T crysta6lized .gabbro magma as 12000, syenitic 900C and 800-7000 for granitic, that are similar with data F. G. Smith. From Winkler's data T host rocks is 1500 ~?} only. The metasornatic process of alteratian of dolomite started in halo intrusion under action magmatic Si and AI-bearing solution and give primitive skarn zonality as first stage process (300-400C}, but .not 150C}. The reaction CaMg[C®3}2 ---> AligO + CaC®3 + C®2 is 600-7--Cf1Km depths (see fig. 1, 14, 19 and 32 in my bock}. [Emphasis by TCM] It is before the complication of zonality skarn column on stage. of melting near-contact rocks, that demand more high T and be accompanied with appearance new zones in column: monforsteritic and enstatitic as plus Mg from melted part of exoskarn. The thickness of high magnesian zones = 1/2 the same [thickness] melted skarns.'This process impossible on contact with SOOC granitic melt. As you think about this? Fram my practical work I see, that near contact with skarn after dolomite, granites may transformed in granodiorite......... up to gabbro under assimiliation of skarn materiaN Qr may be leucocratic granites, too. Alt progressive Mg-skarn processes have place on contact with magmatic melts. After consolidation intrusion, took place regressive transformation the mineralogy of early formed skarns." "The. presence Mg-Fe boraces on Whitehorse and other area is possible. l send you copy ofi Thompson & Gower article." "i send you my book in English (15th November) , bibliography (articles published in English}, and a copy of my former essay about ludwigites in first edition"of "Geochemistry", that received good compliment from W. T. Schaller many years. ago." 13 GMG DATA REPORT 3 4 4 Fage l5/11~ Selected portions of a letter from SP~lA to TCM, March 15, 200: "You are doing the large investigation and .supported magnesian skarn nature of Arctic Chief!!! It is good start for future regional observations in Canadian deposits!" .......... [Emphasis by TCMj "First commentaries fore your samplesa Common look - as also in Brooks Mountain and Tin Creek [Seward Peninsula, Alaska] in Arctic -Chief rocles. [Emphasis by TCMj You can see rhythmically-banded textures, that inherit, and in magnetite ores. (Thebest you can see in TM-04-10-12-22-b-104 --- [the sequence] around diorites'. injection in marbles: exchanged [°altered"j diorite--clinozoisite rim--pyroxene skarn--banded. ludwigite-bearing forsteritic calciphyre--banded periclase (brucite) marble; in TM-04- 10-12-22-a-134 and -131 and -102 --- banded phlogopite--magnetite ores, in -126 -- - serpentine/forsterite rhythm in magnetite; in TM-04-6_g_4_2 ___ is .forsterite-- calcite rhythm, etc....}. [Underlining emphasis by TGMj These textures have origin on progressive stage of metasomatic exchange of dolomites and reflected in ores-- see book [SMA, 1998], pages 77-87. It is non-equii'sbrium process. My first question: what is position these little finger-like projections of diorites in marbles find on contact with big (main) intrusive massif? It [`projection/s'j is shown in a few of your samples! You can see SimilaP [features] in a few figures in book [SMA,1998j from skarn areas. PJext my second question: Magnetite is absent near those injections in marbles. What is position magnetite ores in metasomatic contact? They are only in immediate contact zone of big intrusion? In your collection is splendid periclase marbles, but in literature are not this in#ormation. In many samtales in marbles_ _and_ _forsterite.-calcite _environment are a bit to big black crystals of LUDWICITE see TM-04-10-12-22-b-115; -23-110 -23-108} etc. See Brooks Mountain! This fully are not in literature about Whitehorse copper belt! [Underlining in above is original in letter from SMA; bold emphasis added by TC(Vl.j Third: In your collection I can not see monomineralic forsterite skarn, only calciphyres! You check up this fact? The presence the last [monomirieralic forsterite skarn] is possible after magmatic melting of the pyroxene skarns (see exchange types of zonality --- see it in book [SMR,1998j). About typical lime skarn (TM-04-OS-09-2) [ofj pyroxene-garnet composition: What is its position with magnesian skarns? I believe that it has postmagmatic origin from Si-bearing marbles. What, how much; are sulfides in this type skarns?? Gr absent? ~~~ l~~1r~ R~~ORT 3 4 4 1 4 Page 16/117 In forsterite marble (TM-04-6-9-5-1) is spinal. The part of pyroxenes is A!-bearing. In this situation is formed late phlogopites in rocks and ores ............. Conclusion: Contact aureole at Arctic Chief was formed in n®rmai dolomites. tts tonality is near the primitive type, but it is [iniof] the hypabyssal periclase facies (see pages 31-37, and fig. 24, in book [SfiAA,1998]) in the time of progressive metasomatism of these rocks. The first postmagmatic ore mineral in marbles is ludwigite; after forsterite formed clinohumite (TM=Q4-6-S-4- 2) and phlogopite after spinet. The part magnetite is inherit texture of calciphyres, other - the same with phiogopite - from pyroxenic skarns. Ail sulfides are late. [Emphasis by TCM.] In t~hitehorse copper belt are [many] deposits and. prospects............ [How manylwhat proportion] of [these] are seated in dolomitic rocks? !f only part of [this total], what are the differences in the composition of skarns and ores composition in not-dolomitic environment?" ['~1/hich of course is another matter/study yet to be dealt with. {TCM}] Selected portions of a letter from SMA to TCM, June 16, 2005: "Answers to your questions: 1. For study (investigation) all pure dolomites, periclase marbles and forsterite + spinal caiciphyres [it is] very useful to see its weathering surface. You can see a!1 silicates as prominences, but in pla`e of brucite will be caverns± It is important to watch4Ef [Emphasis by TCM. Remindful once more of the personalltearning experience on Brooks Mountain in1973, recounted previously, above.] 2. About magnetite ores in skarns. Yes, it is common in direct contacts with main intrusive bodies, but near magmatic injections in marbles are rare. Presence iron you can see as ludwigite or late sulphides (pyrite and pyrrhotite). Magnetite is often replaced of silicates in skarns. All iron is coming from solutions in time of postmagmatically exchanged iron-rich minerals in basic. intrusive rocks. Only from leucocratic granitic magmas Fe is going on magmatic stage and giving magnetites of syngenetic with the formation of magnesian skarn tonality (see book [SMA,199131). 3. Monomineralic forsterite skarn zone [indicates] magmatic stage replacement of magnesian skarns near intrusive rocks by melt. Half thickness of monoforsterite zone =thickness melted skarns. 4. Typical skarns are formed. after postmagmatically changed silicate- hearing carbonate rocks. After pyroxenes is formed zoning garnet. `Arsenopyrite'? in sulphide ore can be ioellingite -FeAs2l1! Check it!!1 (Emphasis by TCM] 5. The CaCO3 marbles in contacts with granodiorite melts are not transformed into skarn. Ca is assimilated by melts and involved in Ca- bearing minerals - plagioclase, hornblende and etc. CO2 increases," (Emphasis by TCM] 15 GI~C DATA REPORT 3 4 4 Page 17/117 Selected portions of a letter from SMA to TCM, June 25, 2005: "About dykes and its composition. In cast letter I note about leucocratic hornblende quartz monzonite dyke. !t is possible that monzonite from massif viii be more basic! If this so {well then{ you can think that monzonite magma of massif is result of assimilation of host rocks and primary melt was mare close to granitic composition and was superheated. t_ast dykes from deepest magmatic camera must be leucocratic. In book [SMA, 7998] (FicJ. 13} is illustrated this, and similar with Arctic Chief locality. [Emphasis by TCM]. (In text, epidote = ciinozoisite). Plus, see green amphibole with plagioclase in quartz-monzonite dyke- TM-04-7 0-12-23-108, ~ ~ 0 with pyroxenes and quartz." Selected portions of a letter from SMA to TCM, January i 1, 2006: "I am believed that Arctic Chief and other deposits in Whitehorse ore belt are best objects for investigation position and coning Mg-skarns and ores in its. The understanding of genesis and mineralogy must be given the key in exploration (discovering} new ore bodies in skarns and marbles and its relation with placer accumulation of gold in Yukon region in all.. (Bold emphasis is by TCM; underlining is by SMA] In my works 1 only. want to demonstrate (show} that skarns after dolomites are sources many metals and yaws [materials] in any parts of all world. ®f course in past and to-day .its was minim and without this understanding, but splay [applied] geochemistry may be given good results for its prognose." [Emphasis by TCM] Selected portions of a letter from SMA to TCM, May 11, 2006: "Your commentary in letters, best slides [photographic] from. quarry, and, of course, the good samples has given me the possibility. to support the. magnesian skarn nature of (this) Canadian Fe-Cu-dep®sits in Whitehorse ore belt." "Your last samples is very besto its iiiustrateci of rhythmically-banded structure of metasomatites ll!" [Emphasis by TCM] ®ther selected comments (SMA}: `Periclase marble' lie. marble featuring brucite after periclase, and calcite, +f-] is the. predominant `host rock' represented in the [many] specimens studied. [Emphasis by TCM] Forsterite and low-F clinohumite occurs in caiciphyres. 16 GMC DATA REPORT 3 4 4 Page is/11~ Phlogopite-magnetite ores. Zoisite occurs after plagioclase-pyraxene zone (ar diorite) in rocks studied. Irt comparison with the areas such as Lost River, Br®®ks Mounfain, Tin Creek, etc. on the western Seward Peninsula, Alaska, [where SMA and TCM w®rked together in 1973 and 19797 at the Arctic Chief locality the situation appears to be not as comple~c. [Emphasis by TCM] QBSERiiATI®NS ®N SPECIFIC SPECIMENS (S. M. ALEKSAN®R®~): TM-05-5-25-1-Q: "Probably in this specimen is iudwigite in the marble pact near contact Frith forsterite- magnetite ore. .........." "Marble with iudwigite {??????) as black .needles . ............" "i will be send you new j[microprobe]] analytical data for sample #TM-05-5-25-1-C~ (marble with Ldw?????? and + magnetite ors............ }° [An excerpt from a letter from SMA to TCM, May 1 i , 2006 states: "All black needles are pseudomorphoses magnetite after borates .............~] "Other minerals in this specimen: Mg-bearing magnetite- {>90% FeO, and 1.5% Mg0) Dolomite- (22% MgO, 30% Ca0) Serpentine- (36% MgO, 3% FeO, 45% Si02} Phlogopite, altered to clinochlore- (with MgO, Si02, and AI2®3) Talc- (MgQ, SiO2} Are [also] Fe-Mn species doiomitefankerite." Selected portions of a letter from SMA to TCM, June 16, 20D5: "Ludwigite is in serpentine-bearing marble TM-[04]-10-12-22-B-104, very little. May be in c®ntact with marbles you can see k®toite Mg3(B03)2??? [Emphasis by TCM] Near monzonite plag and prx -- transformed into zoisite and calcite; and prx -- into Mg phiogopite. Ali periclase in marbles fully transformed to brucite, with calcite; its form is pseudomorphic after periclase. In these rocks are a few grains of forsterite and ciinohumite. In magnetite ores forsterite is transformed into serpentine near calciphyres, or into other silicates --- into Mg-phlogopites {after diopside). Mg-pyroxene is in TM-04-10-12- 22-A-137 and actinolite........ 22-B-117, amphiboles........ 22-A-101. Green amphibole with plagioclase in quartz-monzonite dyke- TM-----23-108, 110 with pyroxenes." ..................................................................................................................................................... 17 GNiC DATA REPORT 3 4 4 Page 19/117 ether comments ®n setected specimens (SMA): TM-04-10-12-23-111: Skarned zone on contact with dike. Content anorthite, pyroxenes (fassaites) and garnet. The typical in contact magnesian skarn plagioclase-pyroxene composition and secondary [-ily] transformed in [into] sa[ite-garnet bearing associations. Microprobe analysis: P-67-1. Saute, plagioclase (anorthite}, garnet (grossularite 70%, andradite 30%), pyroxene. TM-04-10-i 2-22-8-104: Forsterite-bearing brucite (after periclase) marble, with calcite, serpentine and phlogopite. Microprobe analysis: P-67-2. Forsterite, serpentine, brucite, phlogopite. TM-04-10-12-22-B-119: Brucite-periclase marble. Microprobe analysis: P-68-1. Brucite with relicts of periclase, and dolomite + spinal + hydrotalcite {after. spinal). and magnetite. TM-04-1 0-1 2-22-A-1 1 3: Brucite-periclase marble, with forsterite and clinohumite. Microprobe analysis: P-68-2. Brucite and periclase, some dolomite. TM-04-1 0-1 2-23-8-1 1 5: Brucite (after periclase). marble with forsterite. TM-04-10-12-23-110: Plagioclase rock with hornblende and pyroxene {dike?). TM-04=10-12-23-109: Clinohumite calciphyre with magnetite. TM-04-8-9-2-Z: ~'esuvianite (idocrase}-pyroxenic typical barren skarn. TM-04-1 0-1 2-22-A-1 30: Magnetite ore with phlogopite. TM-04-10-12-23-108: Plagioclase rock with amphibole (dike???}. TM-04-10-1 2-22-8-1 41 Magnetite ore with serpentine. TM-04-1 0-1 2-22-A-1 31 : Magnetite ore with phlogopite; magnetite is prismatic. TM -04-1 0-1 2-22-A-1 34: Magnetite are with phlogopite; magnetite is prismatic. 18 Gl~C DATA REPORT 3 4 q Page 20/117 TM-04-1 0-1 2-22-A-1 32: Magnetite. ore with phlogopite; magnetite is pr{smatic. TM-04-1 0-1 2-22-A-1 35: Magnetite ore with phlogopite; magnetite is prismatic. TM-04-1 0-1 2-22-A-1 37: Diopsidic skarn with .prismatic magnetite. TM-04-1 0-1 2-22-A-1 33: Phlogopite-magnetite ore. TM-04-10-12-A-126: Rhythmically-banded serpentine-magnetite ore. TM-04-10-12-23-106: Rhythmically-banded serpentine-magnetite ore. Serpentine after forsterite. TM-04-1 0-1 2-22-8-1 1 4: Rhythmically-banded serpentine-magnetite are. serpentine after forsterite. TM-04-1 0-1 2-22-A-1 01 Actinolite in magnetite ore. TM-04-1 0-1 2-22-B-1 1 7: Actinolite after diopside, in magnetite ore. TM-04-1 0-1 2-22-A-1 21 : Ph{ogopite in magnetite ore. TM-05-10-13: Rhythmic-banded marble with sulphides. FIELD L®CATI®NS, INF®RMATION, GENERAL REMARKS, (TCM) ON S®ME SAMPLES STUDIED BY S. M. ALEKSANDR®V. (REFER T® PART 2 ®F THIS REPORT, THE "DATA SUPPLEMENT' ADDENDUM, F®R MAPS, QTHER DETAILS)e TM-04-6-9-4-2: Just across (the pit entrance) from locality #-3 (see insert below), to the south"ish". Samples and photos (some "te{e-") {ooking northward at locality #-3, and. around the pit to the west. Samples essentially in place/rubbleerop. Note interesting structures in the carbonate rocks and associated skarn materials (across pit entrance) as shown in these photos. [[[T M - 0 4 - 6 - 9 - 3: Location at "west" pit, along "northeast" rim, lust above the entrance to the pit. Samples in p{ace, or immediately be{ow outcrops difficult to work on atone. Carbonate rocks near/adjacent to skarn +/- "calciphyre(s}"?/+I-? (the skarn here appears to occur as an "apophysis" [an originally igneous "core"fcentral portion?)/projection/"finger"Hens-like mass intofwithin the carbonates). Analogous to/is a crushed zone" (cf. SMA} setting? 18 GMC DATA REPORT 3 4 4 Page 21/117 "Dike" rocks, etc., vs. "hard' carbonate rocks. °Corttact" between "skarn"/"carbonate" rocks. "Dikes" _ "plagioclase-pyroxene" rocks of SMA? (ef. photos from across pit mouth, with- view toward localities "-3" ,and "-5"}. (Some ofJ these "dikes" appear (cf. photos from TM-04-6-9-4 locale} to be "tongues" of "skarn/intrusive racks" {??) into the carbonates(?) This Eocality is just southeast of locality #-04-6-5-1.]j] TEA-fl4-6-9-5-1 Just "east-ish" of locality #-3 (see abovej, on northeast side of pit. Qutcrop and subcrop samples; skarns, carbonate rocks, etc. Apparently some "brown specks" {"brucite, after periclase"?land/or "spine)?) in some of the. carbonate rock samples? These carbonate +l- rocks apparently (?) are more. distal from the skarn "lens/patchlintrusive(?) apophysts/projection" exposure mentioned previously. However---- .note "endoskarn/diorite/ic" (?) samples here; thus the carbonate rocks from. #-3 and #-4 may -- or may not -- be more "proximal° {?} than those from #-5. Cf. also the following -- quite speculative, at o3est --remarks ("musings on the outcrop", as it were; "stream-of-consiousness"J, taken from today's field notes (9 June04-31TM- 04-6-9-3), regarding "dike rocks", etc., elsewhere/nearby: [[Relationship to/with/of the "mafic{?} dike{s}(?) ..Which fithotogtes (porphyritic {light buff-colored phenocrysts of altered plagioclase(?), +f-}, with green-grey fine- grained matrix; the rocks are hard/"ringing"/"bell-banging" when hammered, producing sharp-edged fragments) are in evidence in rubbiecrop here?? Might these so-called dikes actually represent marginal portions --offshoots/border zones/"chills"irapidty-tooted variants-- of the main {granodioritic/granitic?} magma (perhaps modified via contamination)"basification" by assimilation/reaction with intruded rocks/carbonates) {cf. TM-04-6-9-3-2, an apparent "plagioclase -pyroxene" rock of interesting "salt-and-pepper" aspect/possibly-likely igneous texture??}; this "main magma" responsible {thermally and geochemically} for the bulk of the metamorphism/metasomatism at the AC?? Are these "dike" rocks and/or the/any other "skarn" rocks here at this sample site/locality at least in part "endoskarn°, at least in a certain. sense/one sense or another?? Fine grained/porphyritic, rapidly-coaled/quenched variants of a "dioritic")more mafic magmatic type? With plagioclase{?} phenocrysts having formed initially during "basification" of the main magma, at the periphery of the main intrusive body, and "quenching" of the matrix subsequently during injection into country rocks as "basified" magma. at elevated temperatures?? With perhaps some, or perhaps relatively. little/none, metamorphic/metasomatic effects {even at the relatively high temperatures likely extant, due to the relatively small volume of these meth materials as well as perhaps the physical conditions leading to/permitting their migration/intrusion into the country rocks} on adjacent surrounding country rocks into which this partiadly crystallized .mafic melt was intruded??)?? (!e. relatively rapid intrusion, perhaps. due to tectonic .activity/fracturing of country rocks, .with- attendant pressure droplrelease, cooling, etc. ??} Perhaps aided and abetted in their distribution, emplacement, cooling and solidification by structural/tectonic events/features, in particular fracturesffracture zones, perhaps related to the "contraction phenomenon" associated with the evolution of the main magma body(ies), as discussed/espoused by Aleksandrov?? {ie. perhaps representatives of the "main magma" extant at depth subsequent to the metamorphic and' metasomatic events/conditions attendant to the formation of the skarns and related mineralization??}. "Long-iived° (or perhaps only relatively short-fivedj tectonic "crush zones", ie. Featuring/affording porous and permeable zones, reduced pressures, Eocalty andlor for 20 Gi~C DATA REPORT 3 4 4 Page 22/117 relatively brief periods of time, perhaps facilitating migration/"flight"!escape of more basic![ess silicic, higher temperature, lower viscosity -melt materials as "fugitives", in a sense, from the bulk heat source of the main magma body?? With or withoi.Et assistance from tectonic manifestations related to physical differences in main magma body versus surrounding rocks, in addition to heat differentials/gradients. !s the somewhat casual treatment of these dikes", etc., especially in terms of their influence/relevanceisignificance with regard to the "main magma", and/or metamorphism- metasomatism-mineralization, as dealt with in the extant literature, perhaps worthy of .some reviewfreconsideration??? While of course there may well be a variety of types and compositions of {apparent} "dikes/tongues/lenses/apophyses" involved here. NOTIONS WORTH LOOKING INTO FURTHER?? . Cf. (below, locality #-4) photos (some "tele-") from opposite ("south") rim. of pit, featuring views of locality #-3. j)~ Localities. todayldiscussed-above are atE "outside/on the periphery" of the. (western)most pit of the two pits to be seen here at the Arctic Chief ("AC"). ie. the "AC (west)" pit. TM-04-8-9-2: Garnet-pyroxene, +/-, "skarn". specimens collected from "rabbis-floats (likely "out- of-place") at map location # "Z", from atop the "northeast" rim of the AC (west) pit. TM-04-8-9-2-Z: Garnet-pyroxene, +/-, "skarnn, "ore", +/-, specimens collected .from "rubble- crops -- likely not far from. bedrock source -- atop the the "southeast rim (map location #21) of the AC (west) pit. Garnet-pyroxene, +/- "skarn": samples collected feature occasional patches of orange- pink carbonate%aicite, and other minerals, present in minor amounts. One specimen representative of this ("gaudy') skarn examined by SNIA was summarized as "vesuvianite (idocrase)-pyroxenic typical barren skarn'. TM-04-10-1~-22-A-e Samples -- some "banded" -- of "ore" (ie. magnetite +/- barnite? +/- chalcopyrite +/-?), as well as other lithologies, from the AC (west) pit. Locality (map #22A) is uphill , on the south side of the pit entrance (in approximately the same location as the TM-6-9-4 area). Rubble-crop/rubble samples. Some samples likely essentially in-place. Several "in- place°/rubble-crop specimens of skarn, ores, and other lithologies were obtained from map location #22). TM-04-1 Q~-1 2-22-~-: Samples -- some "banded -- of "ore" (ie. magnetite +/- bornite? +l- ehalcopyrite +/-?j, as weft as other lithologies, from the AC (west) pit. Locality is map location..#22B, in the pit entrance, and beyond, inside the pit. Sub-crop/rubble-crop/rubble samples. Some samples likely essentially in-place. Several "non-ore specimens of skarn, etc. (same from below the TM-04-6-5-3 area). TM-04-10-~ 2-22-B-104: E[IExz>.~xxllll This is the specimen sent in its entirety to S.kR. Aieksandrov. Studied by him, depicted and discussed in his paper "Gold Behavior during Endogenic and Supergene Alterations of Sulfides in Magnesian Skarns", in Geochemistry international, 20(37. Cf. the "References" section of the present report, as well as the. section above containing commentis by TCM on this paper. 21 GMC DATA REPORT 3 4 4 Page 23/117 Described in his "triage" phase of analysis by TCM as a "VERY NICE SFEClMEN°. Collected as "sub-crop" in the near vicinity of a larger skarnfapophysisllens of tongue-like aspect, featuring zoned igneous .and "skarn" materials within carbonate host rocks, with .green +/- blue copper-staining present in places along its margins ("gaudy", rather spectacular, -well- photographed, 2004 and later; as well as subsequently, in 2008, collected in detail as "TM- 06-8-22-2--"}. Cf. TCM descriptions, etc. in the "Data Supplement° of the present report. Location at the northern edge/margin of the entrance cut of the Arctic Chief (vuest) pit, up on the wall of the cut, In the vicinity of the corelcrest of the tighVoverturned fold- in the carbonate host rocks. Below map#3 (ie. TM-04-6-9-3 locality). TM-04-10-12-23-: Samples of "granitics°, "ores", and other lithoiogies. The "granitics" likely represent "casted" and/or rubble-crop materia! from the "southern" headwall area of .the AC (east) pit. The other samples appear more likely to represent materials of/derived (via downhill movement) from rocks peripheral to the "eastern rim" of the AC (west pit. Map locality #23. Below, and approximately east-northeast, of locality TM-04-6-9-4, and map. locality #22A. TAA-O~-.~s-2a-1: Samples from TM-04-6-S-3lmap # area "C° lie. "#3") locale. "Olken rocks, ete., vs. "hard" carbonate rocks. "Contact' between "dike"I"skarn"(?)1 "carbonates rocks. These "dikes" appear (cf. photos from TM-04-6-9-4 locale} to perhaps (?} be "tongues of intrusivelintrusive-related "skarn" rocks" (?) into the carbonates Or, rather, "merely" dikes from magma intruded eitherforfali (?) prior to fduringlsubsequent to the "main magma" events?) which were responsible for the formation (viz. metamorphism and metasomatism) of the skarns and ore mineralization. ®r, rather, both/a{l of these (??). Samples represent outcrop/rubble-crop materials, either in-place or net at all far from being actually in-place. Many of these specimens were obtained in-place, at some varying degrees of "awkwardnessnlhazard; from the very "brink° of the (overhanging} pit rim. Specimens of carbonate rocks, porphyritic as well as more equigranular ("dioritic°?) igneous-appearing rocks (this locality is at the "massive" exposure, not the "bird° exposure; cf. photos and legends, 2004}, "skarns" (with magnetite, +t-}. Some examples of "lenses/intrusions/zones° featuring garnet, pyroxene, magnetite, +/-, .adjacent to carbonate host racks. (Some photos of latter occurrences}. These rocks occur in a three-part (or more} sequence, from (from "left to right"/"southish" to "northish"; cf. photos} the "igneous"!"dike" rocks, through. a "black' material interval, and thence into whitish/light grey carbonate rocks. There is some/a fair amount of smaller-scale "intermingiingfl .between adjacent "zones" of this sequence (cf. samples}. Some interesting structures/textures are manifest in some of these specimens. The "black" interval appears megascopicallyifrom adistance to perhaps represent at least in part a "sheared° interval° (with apparent slickensides, etc. noted on closer examination, in places). The "blackishn material appears at least in part to be chlorite "Scenarios° for this 6ocality might include: 1. "Black" material/zone =contact metamorphic/metasomatic product(s) of dike magma intrusive into the carbonate rocks (the carbonates either .previously.. unaffected by "skarningn event(s)f"meta"-processes, prior to intrusion of dike magma (?}. 2. "Black" materiaitzone = a zone of shear/cataclastic materiaislgouge, resulting from structural movement and attendant deformation along the dikelcarbonate rocks contact zone 22 GMC DATA REPORT 3 4 4 Page 24/117 subsequent to solidification ofdike rocks (with similar possible scenarios as suggested In #1, above, as to .nature/timing/sequence of metamorphic and/or metasomatic effects/events (?). 3. "Qike" magma coeval with, or an apophysis of, the "main magma" which was responsible for the overall contact metamorphismlmetasomatism of the AC (west) deposit. and related surrounding rocks. Or subsequent to this? Or prior to this? A reasonable guess/"interpretation" suggests that the dike magma is indeed. an offshoot of the main magma, from the relationships .observed at this locale in particular. Some other observations at this locale ("C") seem worthy of note as well: A. Some distance .from this vantage point, in an approximately northwest direction, apparent grey-green rocks/materials can be observed to occur at and near the top ofthe "steep~y- dipping" sheer-faced "North" wall of the pit. These grey-green rocks/materials might well be "on trend" with the "massive exposure' (ie. at locate "C") andlor "the bird' dike rock (also grey-green in aspect) exposures (at the "NE" pit corner rim area, and the "N° entrance to the pit, respectively [cf. 2004 photos, as well as photos taken this date]). Or, these grey-green rocks .near and at the top of the "N" pit wait might (?), alternati~rely, be a continuation (across .the pit, ie.) of a possible. (??) dikelintrusion exposed in the the "S-SE" wall of the pit, adjacent to the .carbonate rocks +!- of locale map#4. (This possible (??) dike/intrusion in the "S-SE" wall of the pit is a "V-shapedn feature, with reddish margins, .shown rather well in photographs [2004, 2Q05] from. the "N-NE° rim of the pit, looking approximately south.) B. Also note photos of the above-described "V-shaped° feature in the "S-SE" wail, as taken from the "NE" corner area on 25 May 2005. Note. especially those featuring the carbonate rocks of map 6ocality #5, with the apparently "on-trend°/equivalent (?) carbonate rocks of map locality #4 in the distance across the pit entrance, with the "V-shapedp feature to the west of the carbonates, in the "S-SE" wall of the pit: C. Need to revisit/check/sample the rim above this "V-shaped" feature, as wail. as the pit below it. unfortunately the pit steep wail itself, further threatened/endangered by its overhanging rim, is not readily accessiblefsampled in-place. This "V-shaped"..feature actually may, rather, be an unmined vestige of the magnetite +f- orebody; or both igneous rock and skarn +/- ore (??). [Subsequent sampling inside the pit suggests the latter to be the case.] Also took other photos from site "C° (and of the site itself as well). TM-05- s-ZS-i-O. "Probably in this specimen is iudwigite in the marble part. near contact with forsterite-magnetite ore. .........." "Marble with iudwigite (??????) as black needles... (SMA)[Emphasis by TCM] TM-Os-10-~3a "Rhythmic-banded marble with sulphides" (SMA). Locality is map location #228. Samples -- some "banded" -- of "ores (ie. magnetite +f- bornite? +/- chalcopyrite +t-), as well as other litholagies, from the AC (west) pit. Locale is in the pit entrance; as well as beyond, inside the pit. Rubble-crop/rubble samples. Some samples essentially in- place. Several "non-ore" specimens of skarn, etc. (some from below the TM-04-6-9-3 area). CflRC DATA REPORT 3 4 4 2 s Page 25/ 117 SUMMARY AND CONGLUSIONSe The present report is intended to convey the following points: These imEestigations were pursued in the context of concepts regarding skarns which have been developed and. elucidated over many years. As summarized and presented by S. M. Aleksandrov in his monograph "Geochemistry of Skarn and Ore Formation in Dolomites" (1998), and also dealt with in numerous other contributions to the technical titerat~ire. Including his recent (Geochemistry International, 200?} paper, a portion of which features the initial publication of our work on the Arctic Chief, and .results, interpretations derived therefrom. Provide a statement of the recognition and confirmed occurrence of periclase (brucite) .marbles at .the Arctic Chief (west} locality. Comment on the significance of the formation of periclase (brucite} marble, in terms of the results of experimental petrology, known phase relationships, etc. Note the importance of this, in the context of this locality, and elsewhere. Emphasize that the formation of periclase, as welt as its (partial to apparently complete) replacement by brucite, both provide substantive insights as to petrogertesis, geochemistry, geological relationships, and mineralization, of potential value in a number of ways. Observe that this apparently "initial recognition" of periclase (brucite} marble at the Arctic Chief (west) suggests that perhaps further reinvestigation/reconsideration is merited of these, as well as associated rocks, "skarns", and mineralization in the area, the region, and elsewhere. Such periclase (+{- brucite) marbles -- and associated{related materials -- perhaps (likely} lurking, as-yet-unrecognized/undetected/(unsought}, elsewhere, in this, and other, regions. With attendant implications regarding any such yet-to-be-recognized. occurrences. Provide as well the intial reported recognition of the presence of "catciphyres" at the Arctic Chief (west) locality. "Marble-like" rocks of predominantly carbonate composition, featuring. a number of key mineralogical, geochemical, and textural characteristics, as well as spatial relationships, indicative of a magnesian skarn situtation. Displaying typical banding of (variously) "rhythmic" character, attesting to metasomatic activity. Note also the initial reported recognition of similar ("rhythmic") .banding in "ore" specimens; featuring magnetite, +/- sulfides, (+{-), and associated "bands"f"layers" of forsterite/serpentine{phlogopite; +/-?. Further indicative of the "magnesian skarn" character of this mineral deposit While also affording significant evidence as to the nature of the deposition of the ore material(s). Provide. the initial reported recognition of the formation. (with subsequent pseudomorphous replacement by .magnetite) of Mg-Fe borate minerals} -- Mg-luclwigite -- in rocks at the Arctic Chief (west). This is of relevance as additional evidence as to the "magnesian-skarn" character of this locality, and is also of decided interest in a number of other ways. GMCDATAREPORT 3 4 4 24 Page 26/117 Thus, to our knowledge, this work has resulted in the first recorded: elucidations, and confirmations, of the presence of periclase (brucite) marbles, associated calciphyres, rhythymic banding in rocks .and in ores, as well as the occurrence of Mg-Fe borate. mineral(s) of the. ludwigite-vonsenite series, at the. Arctic thief (west),. or elsewhere in the Whitehorse area. Compositionally, texturally, spatially manifesting the sequence of geochemical and geo[ogica! events, relationships, recognized and elucidated by Aleksandrov- and co-workers; the "position(s)", and. the "processes" attendant thereto. As recorded in, evidenced by, the rocks and the ores. Featuring, as a matter of "position" {geologically, spatially; as observed in the field), the apparent. relationships {displayed at various scales, up to deposit dimensions) of: igneous rocks of granodioritic-dioritic character; "(calcic-)skarn" materials --- pyroxene, garnet, +/- ; relative to the principal ("ore") occurrences of magnetite and other ore-minerals; the (generally) relatively more "distal" calciphyres; relative to the further-distally-positioned marbles. IndividuaPly, and collectively, these factors provide clear evidence of the "magnesian skarn" nature of this locality. As well as being consistent with the concepts developed by Aleksandrov and colleagues. Supporting a suggestion, here, for consideration of the foregoing, in the ovoral! context of "skarns", related mineralization, etc. Advancing a recommendation for "reconsideration" of (at least some/certain aspects of) "skarn" -- and related ore -- formation. As weal as implications -- geologic, petrogenetic, geochemical; mineral resources. Per Aleksandrov (1998,. 2007, and numerous other contributions to the technical literature). The Arctic Chief {west) locality is demonstrably an example of a "magnesian-skarn". As our work has. further shown, in particular it features a version of "primitive-type zoning", in this case developed/formed under the geological conditions of the "hypabyssal periclase facies", as considered in the context of the mode( of skarnaformation elucidated and refined by Aleksandrov and co-workers over a period of many years.. This model merits attention regarding the nature and origin(s) of "skarns", particularly with regard to those associated .with "host" rocks of "dolomite/dolomitic/magnesium-rich" character. It affords a valuable conceptual, as well as substantively based, framework of theoretical background, fundamental knowledge, and relevant experimental work. As well, it offers ample evidence (the Arctic Chief, as just one example), from a wealth of experience and analytical work, supportive of the validity of this approach to the genesis of skarns. Appreciation, and utilization, of this model ought to be an essential aspect of investigations intended to further the understanding of such geologic occun'eraces. In turn, potentially yielding insights of "more practical" value in the exploration for, evaluation of, and production of mineral resources from deposits related to magnesian skarns. Such has been the case in many areas, worldwide, as attested to by the experiences of Aleksandrov and associates. +GMC DATA REPORT 3 .4 4 ~ ~ page 27/l l,7 Further pursuing this theme ("grinding-of-the-axeR?), to our knowledge, our work, per Aleksandrov's discussion in his 2007 paper, represents the first such. treatment (at least published in the open. literature) of the Arctic Chief from this particular viewpoint of the genesis of skarns and related ore formation. As such, it offers a somevrhat different perspective than apparently has heretofore been brought to bear on this subject, at this particular locality/deposit, or in the Whitehorse Copper Belt, or in the region. This would seem to be a perspective meriting more extensive .appreciation, consideration, application than previously has been the case. Aleksandrov's comments regarding the .Arctic Chief, based on information/data derived from the other sources he cites, in addition to oer own, demonstrate the apparent applicability, "utility", relevance of this "model" to this particular locality/deposit. As well, in the context of this .model, and -its demonstrated usefulness elsewhere, suggesting possible implications with regard to skarn and ore formation in this region too. Qur 2004-2007 investigation also resulted in recognition of same interesting occurrences of molybdenite, and other mineralization, in areas near the Arctic Chief. Aspects of this are discussed in Part 2 of this report, the "Qata Supplement" addendum. Implications of any/ail of the above points, locally, elsewhere in the ~lhitehorse Copper Belt and environs, as well as regionally, remain to be evaluated. As may be appropriate, pursued further. (Per our late lamented colleague R. S. Dietz, who once told me that he "always liked to try putting a little different spin on things".) Communication regarding this work should be addressed to: Thomas C. Mowatt Post Office Box 1438 Haines, Alaska. 99827 USA 26 GMC DATA REPORT 3 q 4 Page 2s/117 ACKNOWLEDGEMENTS: Acknowledgement of .the "scientific/cultural exchange programs° between the governments of the (then) U.S.S.R. and the U.S.A. In the case of the authors of this report, a most successful example of such efforts. In many ways. Would there were more efforts of this sort.......... Stanislav M. Aleksandrov is gratefully acknowledged for all he has done for the authors over the years.. Personally as well as professionally representing one of the more. significant individuals in our lives and careers. Sincerely appreciated, all of it. Thanks, Stan............ 1980-1982 Study- June C. Mowatt, Geologist, (deceased December, 1992) is remembered as wife, and valued professional colleague, of TCM for some thirty-three years. An astute scientist, demonstrating skill and diligence in the field (and underground), laboratory, and office aspects of numerous collaborative geological endeavors, including this study. The cooperative members of the staff of New Imperial Mines responsible for "hosting" those informative "visitations/tours" during 1970 are acknowledged, with sincere appreciation. The generous cooperation and assistance furnished by staff of Whitehorse Copper Mines Ltd. during subsequent 1973 "tour/visitation" occasions, as well as the later 1980-1982 study,. is gratefully acknowledged. This featured valuable office, field, and underground sessions with a number of individuals -- geologists, engineers, and others. Dirk Tempelman-Kluit, Geologist, Geological Survey of Canada, .then on secondary assignment to Whitehorse, was most helpful. Sharing time and ideas, observations and insights; providing encouragement and assistance. All strong determining factors for us at the time. Colleagues with the U. S. Bureau of Mines (1975-1982): John Mulligan, Mining Engineer and Chief, Alaska Field Operations Center: appreciation for support and collegiality over the years. Uldis Jansons, Geological. Engineer: valued colleague since 1961. Among other positions, formerly Chief Exploration .Geologist with Cyprus Anvil Mining Co., Faro, Yukon, for a number of years. Subsequently (1976 - on) with the U. S. Bureau of Mines. Tom Pittman, Mining Engineer: valued colleague. Kevin Weir, Laboratory Technician: appreciation for excellent attitude, admirable aptitude. 2004-2007 Study- Sonya A. Mowatt provided invaluable encouragement and support; as well as assistance in field work, sample-collection/hauling, "bear-watching" services, literature searches, computer work, Russian language knowledge, etc. Not to mention patience and understanding. "JED"....... 27 GMC DA~'A REPORT 3 4~ 4 Page 29/117 Sharon Pries, of the ARLIS Library, Anchorage, Alaska, once again provided invaluable assistance and support. Efficiently providing reference materials, inter-library .loans, theses, copying services, etc. in timely -and useable -fashion. All greatly appreciated. The welcome assistance of Mike Burke, Geologist, Yukon Geological Survey, Whitehorse, has been most helpful. Our "inital contacts in 2004. Continued cooperation, sharing of knowledge, insights, and personal accessibility are greatly appreciated. Mike was also responsible for providing the essential element of an introduction to Jim Coyne.. The subsequent work during 2004-2007 would not have been possible without the continued interest, cooperation and amiable hospitality received from Jim Coyne, Kluane Drilling Ltd., Whitehorse, representing the present owners of the Arctic Chief and some other localities (Special thanks to Jim and Mike for their informative and valuable "tour-guiding° services during initial revisits to the Copper Belt in 2004.) Rick Zuran, Consulting Geologist, Whitehorse, generously provided time; shared knowledge; offered perspective, helpful comments, and insights The knowledgeable staff of the Yukon Energy, Mines and Resources Library, Aimee Ellis, Manager, provided assistance, guidance, and a wealth of information, as well as a place of refuge in which to work. The courtesies extended are greatly appreciated Ron Brockway, Geologist; colleague and friend. Acknowledged for, among :other things, demonstrating by his fine example the level of information to be had "merely° by investigating rocks with the stereo microscope. Providing a most valuable tool; as well as sharing techniques, perspectives, insights. Thanks, for it all, Ron........... Special thanks to James E. Adler, Geologist. President, On-Line Exploration Services, Inc., Anchorage, Alaska. Valued friend and colleague of many years. With appreciable and varied experience in matters related to geology, mineral resources, and mining. Combined. with a special blend of astuteness, acumen, and attitude, as well as an impressive wealth of knowledge related to things. geologic -and otherwise. Making him a resource in himself. Association with Jim, professionally as well as personally, remains stimulating, pleasurable, and rewarding. John W. Reeder, Geologist. Curator, Alaska Geologic Materials Center, Division of Geological and Geophysical Surveys, Department of Natural Resources, State of Alaska, Eagle River, Alaska. Valued colleague and friend for many years. As well a personal acquaintance of S. M. Aleksandrov, from "the. Seward Peninsula days°. One of a kind. In keeping with the facility,. and its contents, entrusted to him. Like Dr. Reeder himself, the "GMC" represents an extremely valuable asset to the State of Alaska, and to alt concerned with the geological. sciences;. energy, mineral and water resources; agricultural, engineering. and environmental concerns. Where else would one choose to deposit samples and data for safe-keeping, as well as availability, and, hopefully, perhaps further use to others? While Alaska and the Yukon Territory are of course "next-door-neighborsA, geologically and otherwise. Thus, with special acknowledgement and appreciation, for many things..... Thanks, John...... The continued interest and support of the Berkeley Blue Group is acknowledged with appreciation. Associates B. Barclay and B. I. G. have provided invaluable assistance,. commentary, perspective, etc. Your knowledge and abilities never cease to amaze.......... 28 GMC DATA REPORT 3 ~ 4 Fage 30/117 Special .acknowledgement to P. M. P. d'le Phrogge, Geologist, retired. Friend and colleague of many years. Generously donating time and talents, as "a perpetual post-doc". A "man of few words", but. a fine "sounding board". Diligent,. reflective. Keen of eye and mind. Doesn't miss much. A °good shipmate". Thanks, Max........ Roman Rudnytsky, Pianist. superb. For valuable musical aaccompaniment". during the course of this project. Recorded. As well as, on two memorable. occasions, in concert. In Haines, Alaska, of all places. Thanks especially for the "Colonial Song", Roman......._ V. I. Vysotsky, "Russian Bard". Appreciation for providing a motto.......... REFERENCES: Aleksandrov, S. M., 1998, Geochemistry of Skarn and Ore Formation in Dolomites; VSP BV, P.O. Box 346, 3700 AH Zeist, The Netherlands; 300 pp. {Note also the "References" section of this book for other relevant publications by Aleksandrov and .colleagues.) Aleksandrov, S. M. , 2007, Gold Behavior during Endogenic and Supergene Alterations of Sulfides in Magnesian Skarns; Geochemistry International, v. 45, no. 2, pp. 152-169, Pleiades Publishing Ltd. (Springer). Boyle, R. W., 1957, An Occurrence of Native Gold in an Ice Lens: Giant Yellowknife Gold Mines, Yellowknife, Northwest Territories; Economic Geology, v.46, pp. 223-227. Dawson, K. M. and R. V. Kirkham, 1996, Skarn Copper, i n Geology of Canadian Mineral Deposit Types, (ed.) O. R. Eckstrand, W. D. Sinclair, and R. I. Thorpe, Geological Survey of Canada, Geology of Canada, no. 8, pp. 460-476. Dick, L. A., 1980, A Comparative Study of the Geology, Mineralogy, and Conditions of Formation of Contact Metasomatic Mineral Deposits in the Northeastern Canadian Cordillera; Unpublished Ph. D. Thesis, Queen's University, Kingston, Ontario,. Canada. Grabber, D. E., 1974, Skarn-Ore Relationships in a Contact Metasomatic Cu-Fe Deposit, Little Chief Mine, Whitehorse, Yukon Territory; Unpublished M. Sc. Thesis, University of Wisconsin. Harada, K., K. Nakao and K. Nagashima, 1973, Valleriite from Little Chief .Mine, Whitehorse copper belt, Yukon, Canada; Mineralogical Journal, v. 7, No. 2, pp. 221-227. Heon, D. (Compiler), 2004, The Whitehorse Copper Belt, Yukon: An Annotated Geology Map; YGS Open File 2004-15. Kindle, E. D., 1964, Capper and Iron Resources, Whitehorse Copper Belt, Yukon .Territory; Geological Survey of Canada, Paper 63-41. Meinert, L. 0., 1986, Gold in Skarns of the Whitehorse Copper Bett, Southern Yukon; in Yukon Geology, Vol. 1, Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, pp. 19-43. 29 Page 31/117 GMC DATA REPORT 3 4 4 Morrison, G., 1976, Granitic Rocks and Associated Mineral Deposits of the.. Whitehorse Map- Area, Yukon Territory; Geof. Association of Canada, Annual Meeting, Edmonton, .Alberta. Morrison, G. W., 1981, Setting and Origin of Skarn Deposits in the Whitehorse Capper Belt, Yukon; Unpublished Ph. D. Thesis, University of Western Ontario, London. Mowatt, T. C., 1984, A Preliminary Investigation of Contact Metasomatic Mineralization from the Cassiterite Creek and Brooks Mountain Areas, Western Seward Peninsula, Alaska, with Regard to Unconventional .Deposits of Tin; U. S. Department of the Interior, Bureau of Mines, Open File Report (unpublished). Mowatt, T. C. and U. Jansons, 1985,. Preliminary Investigation of Acid-leachable Tin Mineralization, Western Seward Peninsula, Alaska; U. S. Department of the Interior, Bureau of Mines, Open File Report No. OFR 32-85. Mowatt,. T. C. and J. C. Mowatt, 1982, An Investigation of Some Mineralogic, Petrologic, Geochemical and Geological Relationships at the Arctic Chief Ore Deposit, Whitehorse Copper Belt, Yukon Territory, Canada. (Final-Draft .Copy of U. S. Department of the Interior, Bureau of Mines, Open File Report. °Lost° by the now-defunct USBM.). Petruk, W., D. C. Harris and E. J. Murray, 1970, An Occurrence of Valleriite from New Imperial Mine, Yukon; Canada Dept. Energy Mines Resources -Mines Branch, Division Report MS PP 70-1, 6 pp. Ramdohr, P., 1980, The Ore Minerals and Their Intergrowths (Second Edition, Two. Volumes); Pergamon Press, New York. Tenney, D., 1981, The Whitehorse Copper Belt: Mining, Exploration and Geology (1967- 1980); Bulletin 1, Geology Section, Yukon Region, Department of Indian and Northern. Affairs, Canada. Thompson, R. M. and J. A. Gower, 1954, A Magnesium Borate from Isere, France, and Swift River, Yukon Territory, with X-ray Powder Data for Some Anhydrous Borates; American Mineralogist, v. 39, No. 5 and 6, pp. 522-525. Turner, F. J.,1968, Metamorphic Petrology; McGraw-Hill Book Company, New York. Uytenbogaardt, W. and E. A. J. Burke, 1971, Tables for Microscopic Identification of Ore Minerals (Second Revised Edition); Elsevier Scientific Publishing Company, New York. Watson, P. H., 1984, The Whitehorse Copper Belt - A Compilation; Exploration and. Geological Services Division -Yukon, Indian and Northern Affairs, Canada, Open File, 1:25,000 Scale Map with Marginal Notes. Wheeler, J. 0., 1961, Whitehorse Map-Area, Yukon Territory 105 D; .Geological Survey of Canada, Memoir 312. Winkler, H. G. F., 1979, Petrogenesis of Metamorphic Rocks; Springer Verlag, New York (Fifth Edition). 30 GMC DATA REPORT 3 4 4 Page 32/117 ISSN 0076-7019, Geachemislry /nlernulional, 2007, Vol. 45; No. 2, pp. 152-169.8 Pleiades Publishing, Ltd. 2007. Origuwl Russian Text ©SM. Atekrandrov, 2007, published in Geokhimi~a, 2007, Nn. 2, pp. 180-198. Gold Behavior during Endogenic and Supergene Alterations of Sulfides in Magnesian Skarns S. M. Aleksandrov Yenladsky Institute of Geochemistry and Analytical Chemistl~; Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia Received March 29, 2005 Abstract-The paper presents materials on the genesis of gold deposits of the magnesian-skarn association. It is demonstrated that sulfides are precipitated at these deposits late in the course of the mineral-forming process and often contain visible and fine gold. Post-sulfide mineral-forming processes resulted in the widespread development of hydroxisulfides: tochilinite and valleriite in high-Mg rocks and borate. ores affected by serpen- tinization, brucitizatin, and szaibelyitization. The newly formed hydrosulfides inherit gold from the replaced sulfides. The endogenic or supergene decomposition of tochilinite and valleriite in endogenic and supergene environments stimulates the dissolution of the fine-grained gold and its remobilization, first,. by hydrothermal solutions and, subsequently, by meteoric waters. The possibility is discussed of the later regeneration of gold as a consequence of electrochemical processes or at geochemical barriers. The deposition of "newly formed" gold in weathering crusts and placers is discussed, along with the significance of this process for assaying the potential of the weathering crusts and placers. It is emphasized that a significant role in this process is played by cryogenic processes, which can increase gold concentrations in naturally occurring solutions and facilitate its later regeneration. The data presented in this paper are compared with data on gold and PGE deposits of other genetic types, which are hosted in ultramafic rocks and carbonatites, i.e., rocks petrochemically similar to mag- nesian Skarns. It is demonstrated that the occurrence of hydroxisulfides in the ores is a significant geochemical and technological problem during the exploration for sulfide ores and their mining and processing. The magne- sian skarn ores of the deposits discussed in this publication were determined to be a significant source of both primary and placer gold and, perhaps, PGE also. The materials presented in the paper. characterize the behavior of gold in the endogenic and supergene processes at magnesian skarn deposits. DO I : 10.1134/S 001670290702004 8 INTRODUCTION Contact metasomatic mineral deposits localized in magnesian Skarns are characterized by a broad spec- tram of mineral resources: large deposits of iron, boron, tin, tungsten, beryllium, lithium, base and. precious metals, etc., as well as economic deposits of sellaite, fluorite, phlogopite, brucite, nephrite, minerals utilized in the ceramic industry and as abrasive materials, gems, and colored stones. Marbles and calciphyres are used in cement production. This genetic group of skarn depos- its still remains, however, poorly examined, as also is the potential of these deposits as sources of gold and accompanying PGE. The main reason for this is the still inadequate scar- city of information on the chemistry and lithology of the host carbonate rocks, which are often combined in geological practice under collective names of lime- stones or marbles, without determining their Mg con- tents, their affiliation with certain types, and the charac- ter oftheir metasomatic alterations. Consequently, even at thoroughly examined deposits, there is often no clear classification oftheir carbonate rocks with limestone or dolomite, whose distinguishing is a problem of great applied significance for the exploration and revision of skarn mineral deposits. Magnesian Skarns are formed via the metasomatic transformation of dolomite in contact with magmatic melts. No ealcic skarns develop after dolomites during the prograde stage, and when more mafic and ultrama- fic melts are emplaced, Skarns at their contacts consist of abyssophobe high-temperature minerals (larnite, spumte, and others). Calcitic rocks and even dolomites are transformed during the postmagmatic stage into caic skams (wollastonite, saute, hedenbergite, and gar- net types), and rocks with rhodochrosite compose their. manganoan varieties. Sulfide ore mineralization is precipitated late in the postmagmatic ore-forming stage and is typical of all types of Skarns. This research is centered on magnesian skarn gold deposits in eastern Transbaikalia (2heleznyi Kryazh, Bystrinskoe, and Kultuma ore fields), Aldan Shield, Norilsk, and the northwestern Baikal area in Russia, at the Hol Kol and Suan region deposits in North Korea, and the Arctic Chief. in the Yukon Terri- tory, Canada (the samples of ores and Skarns were made available for us by courtesy of T.C. Mowatt of the United States Geological Survey). GMC DATA REPORT 3 4 4 ls2 Page 33/117 GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 153 We also used our original materials, as well as those of other researchers, on magnesian skarns in Central Asia and the Carpathian-Balkan region, which were determined to contain sulfides with gold .also. These data were compared with materials on genetically dis- tinct occurrences of precious metals in high-Mg rocks. A feature common for all of these deposits is the devel- opment of post-sulfide mineralization in the gold ores in the form of hydroxisulfides: tochilinite and valleriite. GENESIS AND ZONING OF MAGNESIAN SKARNS The types of skarns recognized according to the lithological compositions of the replaced rocks differ not only in their mineralogy but also in many other genetic aspects. Because of this, Korzhinskii [1] regarded bimetasomatic and contact-metasomatic magne- sian skarns as an individual petrochemical association, which is genetically related to the replacement of dolo- mitesand magnesites, as was proved at numerous deposits in Russia, China, and other countries [2-7]. Prograde-stage magnesianskarns replace.dolomites ai contacts with magmatic melts of various composi- tions (from granites to dunites) [5]. They are character- ized by clearly pronounced metasomatic zoning, which reflects the introduction of magmatogenic Si, AI, and, partly, Fe. Intrusive rocks and their injections. occur in direct contact with the outer-contact rocks, contain their xenoliths, and were not skarnified during this metasomatic stage. The developing metasomatic aureoles have different complicated inner structures, which were controlled by the P-T parameters under which the hypabyssal skarns developed, from the periclase-free metasomatic facies to the gehlenite-merwinite and even spumte-larnite .facies. The magmatic replacement mechanisms of dolomites are also different: they can be infiltration- controlled, .when the magma near the contact does not change its composition, or diffusion-controlled, associ- ated with an increase in the basicity of the magma (from granodiorite to gabbro) and/or its alkalinity (up to nepheline syenite) as a consequence of the assimilation of the host rocks by the magma [7]. Existing data on economic copper and .gold skarn deposits [8, 9] indicate that these deposits are genetically related mostly to intrusions of elevated basicity. The Si02 concentrations in granodiorites and diorites vary from 59.5 to 49 wt %, and these rocks contain 2.5-5 wt % MgO, 6:5-11 wt % CaO, 5.8-10.1 wt % Fe,L03, 4.8-2.6 wt % Na20, and 2.5-0.6 wt % K20, respectively. .The spatial restriction of gold deposits to the outer contacts of intrusions of this composition is clearly pro- nounced in the Altai-Sayan region, eastern Transbaika- Iia, Central Asia [8, 10, 11 ], Canadian Cordilleras [9, 12, 13], and the Rocky Mountains in the United States [14], as well as in several other areas around the world where gold-bearing magnesian skarns were found [14, 15], as, GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 for example, in the Asian portion of the Pacific Ore Belt. Compared to normal granites (with 72 wt % SiOz},the rocks of the succession granodiorite ---- diorite -- gabbro contain more mafic minerals (biotite, pyroxene, amphiboles, and magnetite}, which are able to concen- trate ore elements during magma crystallization and alterations by postmagmatic processes, which modify the original compositions of magmatic rocks and can produce ore mineralization. Magmas of intermediate basicity, with Si02 concen- trations specified above, are higher temperature than granites. The data in [16] on the melting temperatures of anhydrous magmatic rocks as a function of their silicity indicate that rocks of intermediate composition melt at 1220-1025°C, normative granites melt at approximately 800°C, their leucocratic varieties melt at even lower temperatures, and dunites melt at > 1300°C. Skarns develop in dolomites during the heating of the host rocks under the effect of transmagmatic fluids before the emplacement of the melts. Consequently, contact skarns are formed at temperatures close to those of magmatic melts, which assimilate dolomite. marbles that have already been metasomatized. This is reflected in the mineral assemblages of the rocks and in the absence of chill zones in the intrusive rocks in contact with magnesian skarns at the deposits discussed in this paper. The skarns with gold ore mineralization considered here are hypabyssal [5], and hence, their metasomatic aureoles are characterized by primitive zoning: grano- diorite // fassaite and/or diopside skarn (± spinel) ---- forsterite calciphyre (± spinel) -- (±brucitized peri- clase marble) -- dolomite marble. This zoning can be more complicated in contacts with diorites and gabbro, with the appearance of zones made up of high-temper- ature abyssophobe minerals (periclase marbles and monticellite skarns) [17-19]. These magnesian skarns ubiquitously contain no .quartz-bearing .associations, which occasionally occur in the overprinted calcic skarns and their greisenized varieties. The skarn bodies are localized in the contact zones of the intrusions and marbles and/or form steep veins, stockworks, and chimneys up to >400 m long in the latter [5]. Sulfide ores, including those with gold,. in hypabys- sal skarns are very diverse and are deposited during the postmagmatic stage, selectively replacing composition- ally diverse metasomatic zones of the contact aureoles. This can be illustrated by the example of the Arctic Chief Cu-Au deposit, Yukon Territory, Canada. The materials on this deposit were provided for us by cour- tesy of T.C. Mowatt of the United States Geological Survey. His collection of ores and rocks represents magnesian skarns from deposits in the Whitehorse cop- per belt in the upper reaches of the Yukon River, where gold placers are also known. GNlC DATA REPORT 3 4 4 Page 34/117 154 ARCTIC CHIEF SKARNS AND ORE MINERALIZATION ALEKSANDROV In contrast to magnesian skarn deposits in Russia [l-8 and others], their analogues abroad were studied relatively poorly. Literature data on the- Whitehorse belt are scarce [ 12, 13]. It is known that primary lodes mined. in 1967-1982. yielded 10 million tons of ores that contained 121600 tons of copper, 9.7 tons of silver, and 7.7 tons of gold. The dumps of underground and opencast mines (~9 million tons) are thought to contain -1.5 tons of Au, whose contents in the slimes can be as high as 250 ppm. These 32 deposits (including. minor ore occurrences) are under exploration and considered promising as prospecting targets for Cu, Au, and Ag. The ore mineralization is hosted in Triassic rocks domi- nated by dolomites, whereas the quartzites, arkoses, graywackes, and younger porphyry dikes are barren [12]. The gold contents in sulfides from the Arctic Chief and related deposits. vary [12, 13]. Chalcopyrite from the Arctic. Chief deposit occurs in association with gold of the composition 92.29-88.02 wt % Au, 11.52-7.40 wt % Ag, and 0.21-0.40 wt % Cu and contains 0.2 wt % Au, and the bornite and chalcosine contain 0.04 wt % Au each. Valleriite, a younger hydroxisulfide, from the North Star deposit contains 0.05 wt % Au, i.e., as much as in the bornite (0.05-0.06 wt %), whereas the chalcopyrite contains no Au at all [13]. The deposits of the Whitehorse copper belt (Arctic Chief, Little Chief, North Star, and others) are restricted to the western contact of the intrusion and are hosted by metasomatically altered dolomites (Fig. 1). In the aureoles of the massif of biotite-hornblende gra- nodiorites and diorites, these rocks are transformed into magnesian skarns, whose genesis and mineralogy are still known inadequately poorly. Geologists paid much attention to the composition of the Au- and Ag-bearing Cu ore mineralization [12, 13). The results of the exam- ination of skarn and ore samples from T.C. Mowatt's collection (--100 samples) allowed us to partly bridge this gap. The dolomites of the Arctic Chief deposit are monomineralic and were progradely transformed dur- ing the magmatic stage into snow-white periclase mar- bles affected by bru~itization. They compose the outer zone of the contact aureole of the granodiorite massif, whose contact zones consist of hornblende diorites. Closer to the intrusion, marbles give way to a zone of forsterite calciphyres with locally occurring boron min- eralization, which was not found by previous research- ers. The Mg-Fe borates are aggregates of ludwigite crystals. These rocks give way to magnetite ores. At the boundary with the calciphyres, these ores contain for- sterite and show a clearly pronounced rhythmically banded structure with repeatedly alternating monomin- eralic bands of forsterite and magnetite. Note that anal- ogous structures, which were produced already during the prograde metasomatic stage in dolomites, also occur in the periclase marbles and calciphyres. The magnetite ores are of postmagmatic genesis, as follows from the selective replacement of the carbonate constituent of the calciphyres by iron oxides and the preservation of the early forsterite. The rhythmically banded structures of metasomatites and ores were dem- onstrated [3, 5, and others] to have been produced by the thermodynamically unequilibrated process of dolo- mite replacement. According to LR. Prigogine's theory, this is reflected in the spatial self-organization of the minerals. A necessary precondition of this process is the higher rates of the mineral-forming reactions than the inflow rates of endogenic fluids into the skarnified dolomites [3, 5]. Closer to the intrusion, the mineralogy. of the mag- netite ores that replaced the near-contact pyroxene zone of the aureole changes. The ores there contain variable (up to significant) amounts of phlogopite, which partly or completely replaced the spinet-diopside skarns. The barren varieties of the latter are in physical contact with the intrusion.. The metasomatic zoning of the Arctic Chief skarns is generally characterized by the inherit- ance of the Mg/Ca ratio in each zone (excluding that of magnetite) from the pristine dolomites. The structures and compositions of all zones correspond to the P-T conditions of the periclase hypabyssal facies [5]. The magnesian skarns of the Arctic Chief deposit occur not only at contacts with the intrusion but also around injections of diorite melts into dolomites (Fig. 2). The rocks preserve their zoning and inclusions of Mg-ludwigite in the forsterite calciphyres but contain no magnetite ore mineralization. During the postmagmatic stage,. the zones of the contact aureole of magnesian skarns are replaced by magnetite ores, newly formed Mg-bearing minerals, including endogenic borates, and, later, calcic associa- tions. The latter developed in the pyroxene zone, in intrusive rocks in contact with the skarns, and in the vein diorites. The overprinted associations of the pert- claw marbles consist of brucite pseudomorphs and, in the calciphyres, of clinohumite, which locally replaces forsterite, is syngenetic .with the ludwigite, and con- tains <25 mot % of ±he vonsenite end member. The pyroxene zone contains phlogopite and younger salite (which bears 15-22 wt % of the hedenbergite end mem- ber (13]), vesuvianite, and tremolite. The calcic skarn minerals developing after the intrusive rocks are clino- zoisite, epidote, and scapolite. Analogous transforma- tions of the mineralogy of rocks are also typical of the contact zones of many magnesian skarn deposits (5) and are commonly identified in the American Iiterature with postmagmatic-stage calcic skarns proper [13]. Ai deposits in the Whitehorse belt [12, 13], the latter are barren substratiform bodies of salite-garnet compo- sition. They are bimetasomatic in genesis and replace silicate-bearing dolomite intercalations in the carbo- nate sequence. GEOCHEMISTRY INTERNATIONAL Vot. 45 No. 2 2007 GEC DATA P,EPORT 3 4 4 Page X5/117 .GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 155 Via) ~- -I- + + WNiteHoise: .. .... -{- + ~- . , + -~ + -{- -~ -~- + `~ ~' + j / -{- ~- /// 0 200 m s ~ ~ ~ , j/ /// / / + ++ + // / // /// / -}- + + ~- 1 + / -}- + + // + + ~- ~- ~' /////,/ + +i/i//ii/ ~' Legend ®1 ~2 ++3 4~5®6 N ° ° ° ° + + ///j///~/ -~-- Whitehorse copper belt + + ~- + j // /j + + / / / / -~ . -~- _.~. -}- / Legend ® j aka `a°,~ra,; ~f Fairbanks / ~ -~ ~ / ~ ~ ~ ~ ~.~ ' / °°°°° 3 ~ ~ + + ~- + '~ '~ 4 / Yukon Tarirory ~ -1-- -~- :- ~ ~ ~ T ~ . . s ~ ~~. ~.. ° ° + + . wnitehorsc ~` + ~. ~ PACIF/C~ ~ OKEAN b ~.~. .. .: \ 0 0 0 0 0 °o 0 0 0 0 0 ~ ' ~ ~ ° ° ° ° ° ° ° ° ° ° ° o 0 1 2 3klri ~ ia Brirish Colum 2ookm o o ° o ° o o o ° o o o o °°°°°°°°°°°°° Dp °°°°°°°°° °°°° °°°°°a°°°°°°o°°° °°°°°°°°°°°°°°°°° ° ° ° ° ° ° ° ° ° ° o ° ° ° o Fig. 1. Whitehorse copper belt and the Arctic Chief deposit in the Yukon Territory, Canada [17]. (a) Whitehorse copper belt. (1) Triassic dolomites; (2) Triassic terrigenous rocks; (3) conglomerates; (4) Jurassic intrusive rocks (granodiorites and contact- facies diorites); (S) Jurassic skarns with ore mineralization; (6) Quaternary basalts. (b) Map and cross section of the Arctic Chief deposit. (1) Dolomites; (2) quartzites; (3) diorites and granodiorites; (4) skams; (.~ orebodies; (6) postmineral porphyry dikes. Min- eral deposits in the proximity of the town of Whitehorse: (1) Arctic Chief; (2) Little Chief; (3)North Star. GEOCHEMISTRY INTERNATIONAL VoI. 45 No. 2 2007 Page 36/117 +~1~C DATA REPORT 3 4 4 _ -_ _ .: ,~ _. _ ~ ._..._ _..T .,. 15b ALEKSANDROV ,;; _- 111 1 I ~ l l l (I t l \/ 1 ~ ~/ 1) 1' irk / // /ii ~' _ _ _ -_- ~ ~ ~ 'i / 1 ~11 ~11~~1V111`II~\\11111\1{.1 \ I l ll~~~,lrrr //!if'~ Ph ~ I ~iI11111Ld11i1\i \\\\`\~~..~y114 u,1 plll~l L~ 1 *~:/1111\I1\~~~i~ll,it,;\i\'i'i\i,l\iiiFoCai~1;~~\`\` ,~ j i(i~pll 1 /IlU //// // 1 ~ /Il l~k*>Il ~\1\5_ i/////~/1\, \\\l / / 11 11 \ \\M' // ////I/1 ////II////////(111111\V\" 1111 ~`r\\~'3i ~~- i~///'1 `\\~ ~^-~ '''/ /,///101//'11 \\1 211\~~\ . ~,\,~4cm, ~-__ Fig. 2. Diorite injection in dolomite and zoning in magnesian skams. Arctic Chief deposit (sample of T.C: Mowatt). (1) Diorite replaced by 2oisite (Zo); (2) phlogopite-diopside skam (Ph); (3) diopside skarn (Di); (4) rhythmlically banded forsterite calciphyre (FoCa); (5) disseminated crystals of magnesioludwigite (Ld). Magnification 2.5x. Sulfide ore. mineralization at the Arctic Chief and other deposits in the Whitehorse .belt is overprinted onto the skarns and magnetite ores. It consists of lean pyrrhotite disseminations in marbles and calciphyres and of pocket-disseminated Au-bearing pyrrhotite- chalcopyrite and Ag-bearing bornite ores with chal- cosine in magnetite bodies. The ores also contain elec- trum, native Ag, and subordinate amounts of tennantite, tetrahedrite, and Co-, Bi-, and Te-bearing minerals. The chalcosine in association with electrum contains up to 0.54 wt % Te [ 12,13). The ores sometimes contain molyb- denite (T.C. Mowatt, personal communication in 2004). The younger mineral-forming processes resulted in the replacement of the Mg-bearing minerals by brucite, serpentine, and talc. These processes at the Arctic Chief, Little Chief, and North Star deposits were related to the development of valleriite after the gold- bearing sulfide-magnetite ores [ 13, 20, 21 J. The oxidation zone of the sulfide ores Iocally con- tains supergene cuprite, malachite, azurite, and iron hydroxides. The position of the Whitehorse belt in the permafrost zone with acutely continental climate in the Yukon Territory caused the more intense physical weathering of the rocks and ores than the chemical alterations of their minerals. It can be concluded that the skarn deposits of this mining district in Canada show genetic and mineralog- ical features of their ores and rocks, including the pres- ence of Mg-Fe borates, are similar or analogous to gold deposits in Transbaikalia, Aldan Shield, and the Rus- sian Far East, which are localized in metasomatically altered dolomite sequences that were intruded by mag- mas of moderate basicity [5]. Tracing the genetic Links of the gold-sulfide ore mineralization in magnesian skarns with magmas of other composition, it seems to be necessary to consider the setting of the ore mineral- ization at contacts of dolomites with granites or ultra- basic rocks. SKARNS AND ORE MINERALIZATION. IN CONTACTS WITH GRANITES There are still scarce publications dealing with the gold potential of magnesian skams genetically related to granite intrusions. Available data shed light onto the compositional features of the skarns and the P-T con- ditions under which the metasomatic zoning developed in the exoskarn aureoles and which controlled the origin of certain mineral assemblages that predated the sulfide mineralization and were coeval with it [5, 8, 17-19]. The lowest temperature types of skarns are geneti- cally related to intrusions of leucocratic granites and alaskites into dolomites. The inner structures of their bodies correspond to the. primitive type of metasomatic aureoles with the complete inheritance of the MgfCa ratio of each zone from the pristine carbonate rocks. Skams in contacts with granites are often greis- enized, afeature that is weakly pronounced or is abso- lutely absent in contacts with more basic intrusions and is mineralogically accentuated by the occurrence of F-rich minerals (sellaite, fluorite, and fluoborite) that are associated with Sn and rare-metal (Be and Li) and with youngerAu-sulfide ore mineralization [3, 5, 11, 22]. During the pos ;-nagmatic stage, the mineral compo- sition of magnesian skarns is modified, and associated types of magnetite and borate mineralization are formed in these rocks, together with phlogopite and humites. This process is followed by the variably pro- nounced replacement of the metasomatites and nearby intrusive rocks by overprinted calcic skates [2, 5, 22, 23]. This replacement can be seen most clearly in the compositional. modification of the spinet-pyroxene zone in contact with intrusive rocks. The metasomatites are transformed into associations of Fe-rich pyroxenes (saute), clintonite, tremolite, vesuvianite, andradite- grossular garnet, zoisite, and even wollastonite, which are often accompanied. by scheelite mineralization and high-Fe borates (vonsenite and paigeite) [2, 5, 22]. The G" C BATA °fFORT 3 4 ~ GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 Page 37/117 GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 157 near-contact magmatic rocks contain newly formed wollastonite, garnet, epidote, and axinite. The outer zones of the metasomatic aureole (phlogopitized skarns, forsterite- and ciinohumite-bearing calciphyres, brucite-periclase marbles, and dolomites with borate mineralization} are preserved. This confirms that the earlier replaced magnesian and newly formed calcic skarns belong to the magnesian association. It should be mentioned that magnesian skarns and their surrounding carbonate rocks are often "greis- enized" in contact with leucogranites. The F-bearing mineral assemblages are associated with cassiterite and Li-Be ores, which predate the sulfide mineralization. The ores of these deposits are known to contain not only arsenides and various Cu and Fe sulfides but also Au and Ag tellurides and economic concentrations of native Au, Ag, and Bi, which are localized in both the skarns themselves and their greisenized zones, for instance, mica-fluorite rocks. Deposits of this type in Russia are Lupikko in the Pitkjaranta ore field, Karelia, Arkinskoe, and other deposits in the Argun area, eastern Transbaikalia, mag- nesian skarns with ore mineralization in Khabarovsk region (Vostok II) and the Voznesenskoe ore field in Pri- morye in the Russian Far East. The greisens typically contain cassiterite, Li micas. and Be-bearing minerals, including helvite. Fluorite and sellaite develop (often in economic amounts) in dolomitic marbles. Many of these deposits are accompanied by genetically related gold placers. Sulfide and gold ore mineralization of greisenized magnesian skarns in contacts with leucogranites is characterized by the following features. According to E.N. Nefedov (personal communication), he found gold grains at Lupikko in the Pitkjaranta ore field, Karelia, in mica-fluorite rocks, in which gold grains are spatially restricted to the cleavage planes of biotite and occur in association with Ni- and Co-bearing loellingite and Bi minerals. The gold inclusions were formed after the arsenide and are rimmed by younger tellurides. The magnetite .ores contain graphite (?) in association with loellingite, sphalerite, and chalcopyrite and show evi- dence of valleriitization of Cu sulfides (Gerbets I deposit, Pitkjaranta),. a process quite usual at deposits of tl'~is type. SKARNS AND ORE. MINERALIZATION IN EXOSKARNS AT ULTRABASITES The highest temperature type of hypabyssal magne- sianskams develop in dolomites at contacts with ultra- mafic intrusions. The inner structures of their aureoles are largely controlled by the types of magmatic replace- ment of the carbonate rocks. For example, at deposits in the Norilsk district, infil- tration monomineralic forsterite skarns adjacent to monomineralic periclase rocks developed at contacts of dolomites and ultrabasites [24]. The skarns bear eco- nomic Cu-Ni postmagmatic vein-disseminated pyr- rhotite and chalcopyrite .ore mineralization (Table 1) with PGE, Au, and Ag. Diffusion skarn found in the area affiliate with the shallowest depth melilite- and spurrite-merwinite association [25] and are surrounded by periclase marbles (replacing dolomites) in the peripheries. These skarns are also accompanied by sul- fide mineralization. The magnesian skarns developing after dolomite xenoliths in the dunites of the Ioko-Dovyren Massif in northwestern Baikal .area should also be attributed to the low-depth metasomatic facies [24, 26]. These skarns also show evidence of both infiltration and diffu- sion prograde metasomatism, .with. the former. expressed in the transformation of the dolomites into monomineralic forsterite and periclase rocks in contact with dunites [24), and the latter is responsible for the development of amore complicated metasomatic zon- ing in dolomites: dolomite -- periclase marble -- forsterite calciphyre --~ zones of abyssophobe skarns. The abyssophobe skarns belong to the monticellite and gehlenite-merwinite associations [26, 27]. The adja- cent hybrid .melts were characterized by decreasing basicity and crystallized in the form of plagioclase peri- dotites [24, 26]. Both the .skarns and the ultrabasites of the Ioko- Dovyren Massif contain sulfide ore mineralization (pyrrhotite, Co-pentlandite, chalcopyrite, valleriite, and other minerals) accompanied by gold and PGE. This is not the only example of deposits of this type in Siberia. These deposits are known in Transbaikalia (Chiniiskii and Konder massifs) and elsewhere, but their gold potential is still known relatively poorly. PRECIOUS METALS IN THE ORES OF COPPER-NICKEL DEPOSITS AND CARBONATITES Ultramafic rocks accompanied by Cu-Ni deposits in the Norilsk district, near the town of Monchegorsk, in eastern Siberia, and elsewhere [28, 29] and carbonatites with Au-Cu ore mineralization (Kovdor in Karelia [30], Loolekop in South Africa [31], Jacupiranga in Brazil [32], and others) are petrochemicaily compara- ble with magnesian skarns and surrounding them calci- phyres [30, 31] .Similarly to skams, they often have rhythmically banded structures [33], .which reflect the thermodynamically unequilibrated crystallization pro- cesses [3, 5] of carbonatites in hypabyssal environ- ments. Analogously to skarn deposits, they are character- ized by the development of ore mineralization in a high-Mg environment, similar or identical mineral assemblages and the succession of post-sulfide modifi- cations of the mineral composition of the host rocks, including their serpentinization, and the. occurrence of endogenic hydroxisulfides (predominantly valleririte [30, 31, 34-38] and, more rarely, tochilitine) in these rocks. GEOCHEMISTRY INTERNATIONAL Voi_ 45 No. 2 2007 GMC DATA REPORT 3 ~"4 Page 3s/lI7 ls8 ALEKSANDROV Table 1. Composition (wt %) of sulfides in outer-contact disseminated ore, Norilsk deposit Compo- nent 1 2 3 4 S 6 7 8 9 10 1I S 37.39 37.81 34.45 34.35 34.50 34.73 34.12 34.65 34.86 36.40 33.SS As 0.04 0.04 0.04 0.09 0.00 0.00 0.11 0.06 0.08 0.00 0.01 Fe 61.98 60.43 30.89 30.67 30.59 29.92 29.80 3021 25.23 .2.45 2.16 Cu 0.20 0.06 33.11 33.63 .33.22 34.13 33.88 34.23 26.83 O.10 .1.42 Zn 0.06 0.08 0.06 0.07 0.00 0.00 0.02 0.02 0.00 0.01 0.01 Ni 0.87 0.92 0.09 0.00 0.03 0.03 0.01 O.OS 12.21 60.77 b2.62 Co 0.18 0.11 0.00 0.01 0.00. 0.04 O.OS 0.01 0.1 S 0.02 0.00 Si 0.06 0.08 0.40 0.23 0.25 029 0.23 02S 0.02 0.00 0.00 Ca 0.02 0.02 0.34 0.00 0.01 0.01 0.00 0.00 0.01 0.01. 0.02 Mg 0.12 0.25 0.33 0.49. 0.43 O.S8 0.41 0.46 0.06 0.07 0.08 Al 0.00 0.02 0.17 0.07 0.09 0.13 0.08 0.10 0.00 0.06 0.06 Total 99.92 99.82 99.88. 99.62 99.12 99.86 98.71 100.06 99.45 99.89 99.93 trauon proportion Fe 0.935 0.992 1.03 1.02 1.00 0.99 1.00 1.00 0.83 0.04 0.04 Ni O.O1S 0.01 0.00 0.00 0.00 0.00. 0.00 0.00 038 0.91 1.00 Co 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Cu 0.97 0.00 0.97 0.99 0.99 0.99 1.00 1.00 0.78 0.00 0.02 EM 0.95 0.93 2.00 2.01 1.99 1.98 2.00 2.00 1.99 0.95 1.08 S 1.00 1.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 1.00. .1.00 rvote: tt, ~~ ryrrnonte, (S-2S) chalcopynte, (9) Ni-bearing chalcopynte, (10, 11) millerite. Microprobe analyses, analyst V.G. Senin, Ver- nadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. In carbonatites, the former mineral replaces Cu-bearing sulfides (mackinawite, pyrrhotite, chalcopynte, and oth- ers), while the latter replaces pyrrhotite (author's data). Evidence of analogous processes can be observed in sulfide-bearing metasomatically altered dunites of Mount Jumbo, Washington, United States, which con- tain Cr-ludwigite mineralization. In these rocks, chal- copynte is also replaced by vallenite Cuo,82Fet,~S2 1.6(Mgo,~~Alo.z3)(OH)zzs [39] It was mentioned above that dolomites in contact with ultramafic intrusions also contain magnesian skarns. Their sulfide ores commonly contain Ni, Co, interme±allic compounds of PGE, and Atz (including native Au). These facts testify that the ore deposition processes in ultramafics and carbonatites and their subsequent hydrothermal alterations are geochemically compara- blewith analogous processes in magnesian skarns. This also pertains to the endogenic and supergene transfor- mations of minerals containing precious metals in these rocks. Supergene processes responsible for the migration and possible regeneration of gold and PGE during the denudation of hyperbasites, phoscontes, and carbon- atites are still known relatively poorly. These metals are known to occasionally occur in placers, often in the form of large nuggets, which have never been found in the primary rocks, whose concentrations of precious metals are at the Clarke levels. An example is unique placers in the Urals and the Konder deposit in Kha- barovsk region. GENESIS AND COMPOSITION OF SULFIDE ORE MINERALIZATION The deposition of suifide ore mineralization takes place in skarns during the latest postmagmatic stage of the mineralizing process [2, S, 22, 28, 40]. Dolomites at some of these deposits contain anhydrite as a possible source of sulfur. This does not. rule out the significant role of magmatic sulfur, as also follows from its isoto- pic composition in sulfides from these deposits [S]. The ore minerals are S-undersaturated pytrhotite, arsenopyrite or loellingite, chalcopynte, cubanite, and bornite at subordinate amounts of Fe, Cu, Zn, Ag, Bi, Sn, Te, and Se sulfides containing Au in the form of an isomorphic admixture and as a native metal. The ores contain younger As and Sb sulfosalts [4, 22, 28, 41-43] and native Ag and Bi. Pyrite. is rare but is occasionally contained in the marbles and overprinted calcic skarns in the outer and inner contact zones. Sulfides of Fe (pyn hotite and more rare troilite and mackinawite) and Cu (chalcopynte, bornite, cubanite, GMC DATA REPORT 3 4 4 GEOCHEMISTRY INTERNATIONAL Vol. 4S No. 2 2007 Page 39/11 GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 1.59 and others) are typomorphic of all zones of the magne- sian skarn bodies. and often replace earlier magnetite. Loellingite and arsenopyrite additionally replace Fe-Mg borates of the ludwigite and paigeite series [28] or are contained as disseminations and pockets in phlo- gopite and in pyroxene (salite), tremolite, vesuvianite, ~~' and garnet skarns. Other sulfides, sulfosalts, and native metals are disseminated in all of the metasomatic rocks or compose stringers in them. The highest concentra- tions of Bi minerals were found in overprinted calcic skarns, for example, at the Hol Kol deposit in North Korea [2, 5, 22, 40, 42, 44]. Literature on gold deposits of various genesis con- tain information on the occurrence of Co, Ni, and PGM in sulfide ores. Gold and PGE coexist in mineralized magnesian skarns in Siberia (Gornaya Shoriya, Norilsk mining district, northwestern Baikal area, Transbaika- lia, and Khabarovsk krai) [5, 28, 43, 45] in Russia and, in Europe, at the Banat, Romania; Rhodope Mountains, Bulgaria; and elsewhere [41, 46]. GOLD IN ARSENIDES AND SULFIDES Our data on the gold potential of sulfide ores at many magnesian skarn deposits both in Russia and elsewhere [28] make it possible to identify the occur- rence modes of precious metals in them. The loellingite contains variable amounts of Au, up to 0.24 wt % at the Titovskoe borate deposit in the Cherskii Range and 0.33 wt % Au in the greisenized skarns of the Lost River Mine, Alaska, United States. At other deposits, Au concentrations are about 0.04 wt % or below the detection Limit of microprobe analysis. Arsenopyrite from paigeite ores from the Moral'nyi Prospect of the Titovskoe deposit contains 0.08-0.31 wt % Au, and kotoite-bearing calciphyres of the Baita Bihor deposit in Romania, which also bear tellurides, contain up to 0.1 i wt % Au. Arsenopyrite in sulfide ores from the Serdtse-Kamen' deposit in Chukotka was determined to bear up to 0.25% Au. Iron sulfides can also contain gold. For example, troilite in sakhaite rocks from the Dokuchan deposit in the Cherskii Range contain 0.12 wt % Au. More wide- spread pyrrhotite from the ludwigite-bearing calci- phyres of the Lebedinoe deposit in the Aldan Shield contains 0.04-0.12 wt % Au, and the analogous values are 0.06-0.20 wt % for the ludwigite ores of the GoPtsovoe deposit, Cherskii Range, 0.06-0.10 wt % for the Krumovo deposit in Bulgaria, 0.15 wt % for the sulfide-ludwigite ores of Mount Brooks, and 0.08 wt for the Bessie and Maple occurrence in the Lost River ore field in Alaska. Pyrrhotite in ludwigite-magnetite ores from the Dokuchan deposit contain 0.02-0.10 wt % Au. Diopside skarn in Gijhdarva, Tajikistan, contains pyr- rhotite with 0.12-0.16 wt % Au, and this mineral con- tains 0.07-0.1 wt % Au at the nearby Taror deposit and 0.02-0.11 wt % Au in the ludwigite-kotoite marbles at Hol Kol, Suan, North Korea.. Sphaierite often is barren of gold, but marmatite contains 0.06 wt % gold when occurring in ludwigite ores at the Titovskode deposit and 0.05 wt % gold at the Baita Bihor deposit, Banat, Romania. This is likely caused by the occurrence of 2 wt % Cu in ZnS in the form of emulsion chalcopyrite dissemination. chalcopyrite contains variable Au concentrations, which are sometimes. as high as 0.25 wt % in greis- enized skarns with aikinite, bornite, and Bi-bearing minerals at the Karadjhal deposit in the Digilenskie Mountains, in Kazakhstan. Low Au concentrations (no more than 0.04 wt %) were detected in chalcopyrite from valleriitized borate ores from the Zapadnoe deposit in the Bystrinskoe ore field, eastern Transbaika- lia, and 0.01 wt % in sulfide-bearing calciphyres of the Lebedinoe deposit in the Aldan Shield. chalcopyrite in the ores from calciphyres of the Baita Bihor deposit in Banat, Romania, contains. 0.02- 0.15 and 0.30 wt % Au, whereas this mineral from sul- fide-bearing spinel-fassaite skarns of the Traversella deposit, Italy, contains no more than 0.05 wt %. Gold (up to 0.10-0.22 wt %) was detected in chalcopyrite from the ludwigite-bearing calciphyres of the Grizzly Gulch, Little Cottonwood Canyon, Utah, in which chal- copyrite is associated with pyrrhotite and Ag- and Bi- bearing minerals and is replaced by valleriite. Gold (0.02-0.07 wt %) is contained in chalcopyrite from the suanite-ludwigite ores of Blind Mountain, Nevada [28]. This mineral from the Bessie and Maple occurrence, Lost River, Alaska, contains variable Au concentra- tions, from 0.05 to 0.17 and even 0.38 wt %. Pyrite from the Taror skams contains 0.04-0.09 wt % Au, and this mineral from Gijhdarva, Tajikistan, bears more than 0.08-0.32 wt % Au. Analogous gold concentra- tions were found in iron disulfide contained in calci- phyres from the Lebedinoe deposit. High Au contents (0.18-0.23 wt %) were detected in pyrite from ludwig- ite-magnetite ores of the Chingatai deposit in eastern Transbaikalia. Pyrite from Grizzly Gulch, Little Cot- tonwood Canyon, Utah, contains 0.19 wt % Au, and this mineral from the Bessie and Maple occurrence, Lost River, contains 0.42 wt % Au. Pyrite from the Hol Kol deposit in Korea bears 0.36 wt % Au. Younger Cu-bearing sulfides also contain Au. For example, chalcosine from harkerite rocks of Camas Malag, Skye Isle, Scotland, contains 0.12 wt % Au, and the accompanying bornite contains 0.05-0.08 wt % Au. Lead sulfide also contain gold and, often, also silver. Galena from sulfide ores of the Serdtse-Kamen' deposit in the Chukot Peninsula bears up to 0.12 wt % Au. This mineral contains 0.09 wt % Au when occumng in gre- isenized skarns of the Karadjhal deposit in Kazakhstan, 0.05-0.17 wt % Au in calciphyres of Baita Bihor, Roma- nia, 0.05 wt % Au in Skye Isle, Scotland, 0.15 wt % in the Mount Brooks skarns, and 0.11 wt % at the Bessie and Maple occurrence in Alaska. Boulangerite from kotoite marbles from Baita Bihor contains up to 0.21 wt % Au, and tetrahedrite from the Hol Kol deposit, Korea, bears GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 GMC DATA REPORT 3 4 4 Page 40/117 . 160 ALEKSANDROV 0.29-0.33 wt % Au. Molybdenite from this deposit contains variable Au concentrations, from 0.03 to 0.19 and even 0.45 wt %. The data presented above on the gold-bearing sul- fides were obtained by examining hand-specimens of boron-bearing calciphyres, ludwrgite and magnetite ores, and magnesian skarns from the author's collection {5, 28, 40, 47). This study was not associated with the systematic sampling of the orebodies, and the results presented here should be considered provisional and can be taken into account when the gold potential of the sulfide ores of these and other skarn deposits is assayed. Literature data indicate that sulfides (except their Ag-, Bi-, and Te-bearing species) contain almost no iso- morphous Au. Conversely, micrometer-sized to visible inclusions of native gold occur at dislocations of their crystals and in the intergranular space [4), as was con- . firmed by the results of this research. Gold also forms veinlets in skarns and marbles, for example, at the Hol Kol deposit in North Korea, thus reflecting gold migra- tion and redeposition by hydrothermal solutions. The data presented above on gold concentrations in magnesian skarns and the contact zones of leucogran- ites and alaskites that were intensely greisenized with the development of fluorite and F-bearing silicates (norbergite, phlogopite, and Li-micas) and the over- printing ofsulfides and tellurides indicate that this mag- nesian-skarn type of gold mineralization deserves more detailed examination. This also follows from the find of Au (2 ppm), Ag (5 ppm), and Pt (0.5 ppm) in rhythmi- cally banded fluorite metasomatites of the Voznesen- skoe ore field in the Russian Far East [11), which con- tains Be ores. The materials presented above imply that skarns having various mineral composition and affiliating with different facies are favorable for the deposition of sul- fides with gold. Their concentrations can be mined from the orebodies and related placers, as is currently done at some deposits or can be considered for future development with the application of more advanced technologies of the recovery of precious metals. Magnesian skarns at contacts with ultramafic intru- sions also contain sulfides. The hypabyssal spinel- monticellite (±perovskite, melilite, and merwinite) skarns that replaced dolomite xenoliths in dunites in the Ioko-Dovyren Massif, northwestern Baikal area, were determined to contain Co-pentlandite (38.57 wt % Co, 9.63 wt % Ni), mackinawite (9.7-10.6 wt % Co), troi- Iite, galena, clausthalite, native gold, silver, and tin, and valleriite [26). This. is consistent with the composition of the sulfide ore mineralization in the hyperbasites, which contain troilite-pyn'hotite ores with pentlandite, chalcopyrite, and cubanite that contain unevenly dis- tributed PGE and Au. For example, the anorthosites of this i massif contain 4.1 ppm Pt, 7.8 ppm Pd, and 3.2 ppm Au, whereas the Cu-Ni ores in dunites are richer in Pd [26). L The metasomatic aureoles in marbles around hyper- d basite intrusions in the Norilsk mining district are tens o 6MC DATA REPORT 3 4 4 of meters thick. The dolomites are replaced by hypabyssal skarns, calciphyres, and overprinted calcic skarns. Their sulfide ore mineralization corresponds to the types of Cu-Ni pyrrhotite-chalcopyrite-pentlandite ores with cubanite known at the Norilsk I, TaInakh, and Oktyabr'skoe deposits. The ores .ubiquitously contain valleriite (0.5-5 vo1 %) and precious metals: PGE (Pt, Pd, and others), Au, and Ag [33). The ore mineralization in the outer contact zones is hosted in brucite rocks (pyrrhotite, pyrite, and magne- tite), serpentinized magnesian skarns (Table 1), calci- phyres, and calcic skarns (pyrrhotite, pentlandite, chal- copyrite, and millerite). These stringer-disseminated outer-contact ores pervasively contain PGE (0.5-7 ppm pt, 1-35 ppm Pd, and 0.01-0.21 ppm Rh), Au (0.01- 10 ppm), and Ag (0.77-17.6 ppm) [37]. The highest valleriite concentrations were found at the Talnakh (up to 15 vol %) and Oktyabr'skoe (up to 9.5 vol %) deposits (data of V.M. Isoitko, 1978 (37)). This provided grounds to distinguish mil]erite-pyrrhotite- valleriite ores as an individual type, which contains 5-7 vol % hydroxisulfide. This mineral was also found in the mineralized serpentinites and brucitites. Valleriite and tochilinite are formed during the post-sulfide stage (see below) of the hydrothermal process, simultaneously with significant transformations of the mineralogy of the gold-bearing ores. POST SULFIDE MINERAL-FORMING PROCESSES Sulfide ores in magnesian skarns and other rocks of similar petrochemical composition (ultr'abasites and carbonatites) typically contain mixed-layer hydroxisul- fides, such as tochilinite, valleriite, and more rare haa- palaite ((Fe1.26Nio.~a)SZ L61(Mgo.84Feo.i6)(OH)Z and yushkinite V, _XS (Mg,AI)(OH)2) [28, 40, 41, 44]. They replace sulfides and/or magnesioludwigite [2, 28, 40] and are syngenetic with the serpentinization of Mg silicates and, what is important, are coupled with the brucitization of skarn minerals, including Mg oxides and carbonates, and the szaibelyitization of Mg and Mg-Fe boraces [28, 40). Many magnesian-skarn gold deposits at contacts with granitoids, as well as copper- nickel deposits related to uitrabasites and carbonatites, ubiquitously. contain tochilinite 2FeS • 1.67(Mg, Fee+, AI)(OH)2 and, more often, valleriite CuFeSZ • n(Mg, Fe, Al)(OH)Z (Table 2). Their composition reflects both the position of these minerals in the mineralogical system- atics and the occurrence of Mg(OH)2, Fe(OH)2, Mn(OH)2, Al(OH)3, and other components in the oxide group of these minerals [28, 34-36, 38, 40). Valleriite and, later, also tocilinite were first found n Cu-Ni ores genetically related to ultrabasites,, in which hydroxisulfides are often rock-forming minerals. aputina [34) and other researchers [29, 35, 36) have emonstrated that these minerals actively replace vari- us types of sulfide ores, predominantly pyrrhotite, GEOCHEMISTRY INTERNATIONAL Vo1.45 No.2 2007 Page 41/117 GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 161 Table 2. Composition of tochilinite and. valleriite: n(Fe,Cu)~ _~z • m[(Mg, Fe)(OH)2 + Al(OH)3] Deposit Fe Cu EM n S Mg(OH)2 Fe(OH)z Al(OH)3 E m Toc hilinite Zheleznyi Kryazh, Transbaikalia* .1.95 0.05 2.00 2 0.85 0.00 0:15 I.51 1.93 0.01. 1.94 2 0.86 0.05. 0.09 1.49 Titovskoe NE Russia* 1.80 .0.14 1.94 2 0.54 0.23 0.23 1.53 Same* (replacing troilite) 2.00 0.00 Z.00 2 0.88 0.01 0.11 1.38 Same* (replacing pyrrhotite) 1.98 0.00 1.98 2 0.84 0.1 I 0.05 1.40 Gavasai, Kyrgyzstan* 1.86 0.00 1.86 2 0.00 1.00 ? 1.47 Kamaisi, Japan [34] 1.34 0.34 1.68 2 0.78 0.00 0.22 1.67 1.26 0.48 1.74 2 0.79 0.00 0.21 1.65 Pensilvania, United States (38j 1.62 0.00 1.62 2 0.79 0.00 0.21. 1.74 Jacupiranga, Brazi] (C) (32) 1.78 OA0 1.78 2 0.39 0.31 0.30 1.67 Valleriite Zapadnoe, Transbaikalia* 1.12 0.88 2.00 2 0.77 0.23 0.00 1.33 1.37 0.63 2.00 2 0.96 0.00 0.04 1.08. 1.34 0.66 2.00 2 0.94 0.00 0.06 1.16 1.56 0.38 1.94 2 0.91 0.00 0.09 1.47 Kultuma, Transbaikalia* 0.96 1.04 2.00 2 0.90. 0.10 0.00 1.64 0.90 1.01 2.00 2 0.88 0.12 0.00 1.63 Baita Bihor, Romania* 0.93 1.07 2.00 2 0.86 0.14 ? 1.67 Hol Kol, North Korea* 0.98 1.02 .2.00 2 0.85 0.06 0.09 1.24 0.92 1.08 2.00 2 0.87 0.02 0.11 1.35 Grizzly Gulch,. Utah, United States* 0.99 1.01 2.00 2 0.80 0.00 0.20. .1.80 Little Chief, Yukon, Canada [21] 0.81 1.19 2.00 2 0.71 0.06 0.23 1.64 0.80 1.20 2.00 2 0.73 0.21 0.06 1.67 1.07 0.93 2.00 2 0.68 0.00 032 1.53 North Star, Yukon, Canada [13] 0.80 1.20 2.00 2 ? 0.12 ? Kaveltorp, Sweden [38] 1.16 0.84 2.00 2 0.73 0.00 0.27 1.30 Norilsk, Siberia [34] 0.95 1.05 2.00 2 0.86 0.14 - 1.5] Same** 1.61 0.39 2.00 2.2 0.05 - 0.34 1.65 Kovdor, Karelia (C) [30] 1.18 0.82 2.00 2 0.79 - 0.21 1.61 Same (C) 1.47 0.53 2.00 2 0.78 - 0.22 1.63 Loolekop, South Africa (C) [38] 1.03 0.95 1.98 2 0.73 0.00 0.27 1.57 Same (F) (38] 1.02 0.98 2.00 2 0.65 0.34 - 1.70 1.05 0.95 2.00 2 0.76 0.22 0.02 1.66 0.96 1.04. 2.00 2 0.75 0.16. 0.09 1.67 Jumbo, Washington, United States *(D) 1.09 .0.82 .1.91 2.1 0.77 0.00 0.23 .1.60 Note: rrom sulfide-bearing magnesian skarns and calciphyres according to * our (28, 39, 40, 44, and others] and literature data, including hydrozisulfides from sulfide-bearing carbonatites (C), phoscorites (F), and dunites (D). **Valleriite with 61 mol % Ca(OH)2 in its oxide constituent. GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 ~~~, i~H~A REPORT ~ :~ 4 Page 42/117 162 ALEKSANDROV Japan. I. Kusachi found this mineral in association with loellingite, arsenopyrite, chalcopyrite, cubanite, pyr- rhotite, witticherite, and other sulfides (I. Kusachi, per- sonal communication on August 27, 1998). We established [28, 40, 43, 44] that valleriite and tochilinite are .also typomorphic post-sulfide minerals at gold deposits of the magnesian skarn ore association. This significantly expands our knowledge of the occur- rence of hydroxisulfides in various genetic types of sul- fide ores (Table 2). The genetic role of the replacement of Fe and Cu sulfides by hydroxisulfides in the endogenic and super- gene geochemistry of Au and PGE is still poorly under- stood [28, 39, 40, 43, 44]. The significance of the prob- lem of the tochilinization and valleriitizatin of sulfides in serpentinized ultramafic rocks related to the genesis of Cu-Ni ores with PGE and Au was first highlighted by the data obtained by Ramdohr [37] and other researchers. of these minerals [34-36, 38]. Tochilinite and valleriite have a low hardness and are ductile and layered, i.e., .possess characteristics hampering the identification of these minerals. In asso- ciation with pyrrhotite, chalcopyrite, and other sulfides, these minerals are commonly misidentified as graphite based on their optical characteristics. In the ores of Cu- Ni skarn deposits, valleriite and tochilinite develop along the grain boundaries of sulfides and rim sulfide grains (Fig. 3). When these ores are technologically processed (crushed and floated), it is practically impos- sible to get rid of hydroxisulfides, and thus, the techno- logical concentrating process of these ores is associated with significant losses not only of Cu but also of pre- cious metals [31, 48]. As was recently demonstrated in [2, 28, 40, 44], when replacing Au-bearing sulfides, Fe and Cu hydrox- isulfides inherit their Au in the form of fine-grained native metal. For example, tochilinite from Zheleznyi Kryazh, Transbaikalia, contains 0.01--0.4 wt % Au, and valleriite from the Zapadnce deposit contains 0.05-0.15 wt % Au (the chalcopyrite contains 0.04 wt %Au). These concentra- tionsare comparable with those published for deposits in the Whitehorse belt in Canada. In the process of endogenic and stipergene alter- ations, minute gold particles contained in hydroxisul- fides are dissolved more easily than large gold grains (because of the greater specific surface of smaller grains). This process is additionally facilitated by the general chemical instability of tochilinite and valleriite in surface environments. These minerals are replaced by magnetite with the release of dissolvable Mg, Fe, and Cu sulfates. The latter,. in turn, create favorable conditions for gold migration in acid hydrothermal solutions and its redeposition when conditions change, for example, at geochemical barriers (as at .reactions with carbonates). Evidence of this process is the devel- opment of thin veinlets of native gold along cleavage planes of calcite in marbles, for example, at the Hol Kol Cu-Ni, and containing magnesian minerals ones, at the Norilsk group of deposits. The hydroxisulfides have variable compositions (Table 2) of their sulfide and hydroxide constituents at significant structural differ- ences between them [35]. It was established [34] that valleriite of the Norilsk deposits contains 7-16 wt % Cu in pentlandite-chal- copyrite-pyrrhotite ores and 17-22% Cu in the miller- ite-bornite-chalcopyrite and pentlandite-chalcopyrite ores. The pentlandite pyrrhotite ores with subordinate amounts (3 5 vol %) of chalcopyrite contain mostly tochilinite. The composition of the hydroxyl constituent of hydroxisulfides is controlled by the composition of the silicates, first of all, serpentinized forsterite and iron oxides, including magnomagnetite. They are contained in both the magmatic rocks and the adjacent metasoma- tites that replace dolomite and often contain anhydrite. The valleriite of these associations commonly contains Mg (11-12 wt %), whereas the tochilinite bears up to 14 wt % Mg. iiydroxiSiii ;des of other composition (Table 2) occur less frequently at the Norilsk deposits. The mas- sive chalcopyrite, cubanite, and talnakhite ores contain newly formed Mg-free valleriite of the composition CuFeS2. • nFe(OH)2, and tochilinite of the composition 2Fet _ CS • nFe(OH)2 replaces troilite and hexagonal pyr- rhotite in the monticellite skam. The melilite-merwin- ite skarns were determined to contain high-Ca valleriite CuFeS2 - n[(Ca,AI)(OHh], which replaces cubanite and pyrrhotite. The sulfides have variable Cu concentra- tions, from I 1 to 3-4.5 wt % [35). Valleriite (whose composition was not determined) was also found in gehlenite-spurrite skarns of shallow- depth fades at the Fuka deposit, Okayama Prefecture, GMC DA" A R~URT 3 4 4 GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 Page 43/117 Fig. 3. Outer-contact stringer-disseminated copper-nickel ores, Norilsk. Valleriite (Va) surrounds chalcopyrite (Cp) in skams (Sk). Magnification 2x. GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 163 borate magnesian-skarn deposit, the largest in North Korea (author's .data). At this deposit, gold-bearing marbles occur near chalcopyrite-magnesioludwigite ores, which are replaced by valleriite [28, 40, 44]. Eastern Transbaikalia (at the Bystrinskoe, Kol- tuminskoe, 7_heleznyi Kryazh, Arkinskoe, and many other deposits in the Argun-Gazimur divide), .Aldan Shield (Lebedinoe and other deposits), and the Yukon Territory in Canada (Whitehorse copper belt) contain economic gold-bearing alluvial placer deposits. Their genesis was predetermined by the denudation of pri- mary magnesian skarn deposits with gold-bearing sul- fides and. provide evidence of their significant role as a source of placer gold. The gold .potential of these deposits is still not depleted. For example, it is thought that mineralized skarns in the Bystrinskoe field contain 0.6 ppm Au and 1.5% Cu at predicted reserves as large as 130 tons of Au, 4 mil- lion tons of Cu, and 93000 tons of Ag [11]. Placers at the Bystrinskii group of deposits ubiquitously contain scheelite, which was mined in the Bystraya and. Il'dikan river valleys in the 1940s. The sources of the valuable minerals of these placers were the Zapadnoe (Fig. 4), Vostochnoe, Malyi Mednyi Chainik, and other deposits of magnesioludwigite ores with pocket and dissemi- nated pyrrhotite~halcopyrite ore mineralization that is extensively replaced by valleriite during the serpentini- zation of the forsterite skarns and calciphyres and the replacement of the borate ores by szaibelyite [2, 5, 28, 40]. Although the black-sand panning samples contain no preserved minerals of magnesian skams other than magnomagnetite, these samples contain garnet and, near primary deposits, also pyroxenes, scheelite, and gold (905-976 fineness) [28]. When these placers were washed for gold by small diggers, the first priority tar- gets were sands with magnetite and scheelite as those richest in gold. The Zheleznyi Kryazh sulfide-bearing ores and, par- ticularly, the pyrrhotite-bearing borate. ores of the Rud- nichnaya body are also significantly replaced by tochi- linite and valleriite (Fig.. S) [2, 28, 40]. The ludwigite and magnetite ores are localized in magnesian skarns that developed in dolomites of the By strins>;aya Forma- tion of Paleozoic age. They contain up to 29% fine (no larger than 0.07 mm) and coarser grained (up to 1 mm) gold, as well as Iumpy and amoeba-shaped unrounded gold grains in aggregates with chalcopyrite. The denu- dation of the orebodies of the deposit gave rise to related alluvial gold placers in the valley. In the oxidation zone,. sulfides and hydroxisulfides are supergeneously replaced by Fe and Cu hydroxides, which can adsorb Au and release it under the effect of sulfate- and thiosulfate-bearing groundwaters. This can be exemplified by deposits in eastern Transbaikalia, whose tochilinite- and valleriite-bearing ores are trans- formed into magnetite sands loosely cemented with calcite. We identified such newly formed rocks at the GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 Zheleznyi Kryazh and at the Zapadnoe deposit in the Bystrinskoe ore field. At the latter, they occur in the most deeply eroded orebodies in the southern flank of the deposit. At many other skarn deposits, hydroxisulfides are completely oxidized but still can be identified in super- geously unaltered ores [28, 40, 43]. For example, the supergene alteration products of chalcopyrite that has been replaced by valleriite (Table 2) in the ludwigite- bearing calciphyres at Grizzly Gulch in Utah are iron hydroxides and malachite with O.I9-B.52% fine gold. A similar situation occurs at the Kultuma ore field on the Gazimur River, but the predominant primary sul- fide of the boron-bearing skarns and calciphyres is chalcopyrite, which is partly replaced by valleriite [43]. Gold-bearing placers in the valley were mined for more than one century (until 1958) and were thereby repeat- edly rewashed. Genetically analogous placers promising for gold and cassiterite are widespread along some tributaries of the Argun ,in the Bogdatsk-Arkia mining district in Transbaikalia. These placers are. genetically related to sulfide-bearing magnesian skarns with magnetite, cas- siterite, beryllium, and bismuth ore mineralization at contacts with leucogranites [ 11 ]. In the Aldan district in Siberia, gold is produced by the long-term development of the Lebedinoe deposit, which is hosted in skarnified dolomites intruded by Mesozoic syenites [49]. In addition of sulfide ore min- eralization of chalcopyrite, pyrrhotite, and pyrite with subordinate amounts of galena, Bi-bearing minerals, sulfosalts, and tellurides, including calaverite, the mar- bles contain native gold and disseminated magnesi- oludwigite and szaibelyite. Our data indicate that the latter minerals sometimes contain valleriite. Along with primary deposits, gold was extracted in .this area for more than 50 yr from alluvial placers. The reserves of the ore mineralization are comparable with that at the Hol Kol deposit in North Korea. Recently other gold- bearing skarn deposits (Samolazovskoe and others) were found in this area, and this confirms that the area is promising for exploration for gold. "NEW" GOLD IN PLACERS AND WEATHERING CRUSTS The data presented above on the spatial relation of gold placers to its primary deposits call for the analysis of gold geochemistry in supergene environments. In spite of inconsistencies in literature data on the possible scale of supergene gold migration with groundwaters, the possibility of this process is taken for granted and is generally not questioned any. more. This is directly related to the applied aspect of this problem, namely, the possibility of the origin of supergene "new" gold as a consequence of its remobilization and, what is AMC DATA REPORT 3 4 4 Page 44/117 I64 V VI Fig. 4. Map of the Zapadnce deposit, eastern Transbaikalia and profiles across this deposit. (a) Schematic map of the Zapadnoe deposit, eastern Transbaikalia. (]) Hercynian granodiorites; (2) pyroxene skarns; (3) forsterite skarns; (4) ludwigite-magnetite ores. (III-VI) Exploration profile. (b) and (c) Geological profiles across the deposit. (1-3) same as in Fig. 4a; (4) boron-bearing magnetite ores; (5) monomineralic ludwigite ores; (6) postmineral dikes of Mesozoic porphyries; (7) supergeneously altered ludwigite ores; (8) exploration boreholes. particularly important, regeneration when gold-bearing sometimes provokes doubt. This is related, first of all, weathering crusts and placers are formed. to the still poorly understood geochemistry of super- Facts confirming the. occurrence of newly formed gene gold regeneration. gold in placers and weathering crusts are numerous, but The data of Petrovskaya [49), Nikolaeva [50], the role of this phenomenon in the precipitation of eco- Yablokova [51), Novgorodova et al. [52J, and many nomic gold concentrations was not quantified and other researchers indicate that gold migration and rede- G~Qr BATA REPORT 3 ~ A GEOCHEMISTRY INTERNATIONAL .Vol. 45 No. 2 2007 IYili fief f~ 't Page 45/117 ALEKSANDROV GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 165 posrtwn in supergene environments does take place. It was definitely demonstrated that newly formed super- gene gold occurs as thin films, flakes, dendrites, glob- ules, and small crystals. It is believed that gold is trans- ported in both solutions and colloids. The morphology and texture of supergene gold were analyzed by Petrovskaya [49]. It was established that newly formed. gold occurs at several placers in the area along the Lena River in Siberia in the form of spongy crusts and humps at the surface of gold grains or cement these grains. Other researchers confirmed and .specified these observations. According to Nikolaeva [50], newly formed gold was deposited (as humps and crystals) on pale yellow to tin-white silver-bearing rounded gold grains of low fineness. It was found in placers that were produced by the destruction of rocks that had contained sulfides (pyrrhotite and pyrite with inclusions of low-fineness gold 0.01-4 mm across). At the same time, gold was never found in placers produced by the erosion of goid- bearing quartz veins.. Newly formed gold was found in placers in the Aldan Shield by Yablokova [51 ], who determined that rounded coarse-grained gold in these placers is 900 to 923 fine, whereas the newly formed gold is 794-880 fine and clearly differs from the primary gold in texture. Overgrowths of newly formed gold on the primary one are fine-grained, polyhedral, and twinned. According to Novgorodova et al. [52], newly formed gold occurs in weathering crusts in Orenburg Oblast as ungeometrical lumps, angular fragments, and spongy masses of dull brownish and red-brownish .color; the gold grains are never larger than 0.3 mm. In addition to high-fineness (898-982) gold, these researchers docu- mented its new mineralogical mode of occurrence of vio- let-purple and purple color, which consisted of a mixture of gold hydroxide and fine-grained polymineralic aggre- gates of iron hydroxides and iron and bismuth tellurates. These data and other extensive information provides evidence that supergene gold can be formed in placers and weathering crusts and can migrate with groundwa- ters. It was hypothesized [51, 53] that this process can be productive and can even regenerate the gold poten- tial of previously worked out placer deposits. For example, Voronin and Goldberg [54] believe that this process can be facilitated by electrochemical reactions related to a weak electric field around liquid flows filtrating through porous rocks. These researchers demonstrated that the separation of electric charges during the flow of solutions brings about a voltage dif- ference and generates volumetric electric fields, which, in turn, induce the concurrent reactions of cathode reduction (precipitation) and anode oxidation. Elec- tronscan thereby be conducted by particles of gold, sul- fides, and other minerals. It was established that higher concentrations of electrically positive metals (such as Au and PGE) in the solutions are favorable for the more active precipitation of these metals on primary mineral particles. Ag and Cu, which are more electrically nega- tive metals, occur much more rarely in placers. It is thus commonly believed that the margins of gold particles should not become enriched in silver and copper when newly formed gold is precipitated on these particles. It is known that the margins of gold particles some- times have a higher fineness of the gold. The higher fineness of gold particles in the margins is sometimes believed [49 and others] to be caused by the partial depletion of .these particles in silver as a more mobile element in supergene environments. This does not rule out the possibility of the galvanic overgrowths of gold particles with newly formed high-fineness gold in plac- ers. This issue deserves, however, its further studying. In spite of the fact that newly formed gold occurs much less widely than "old" gold in placers, modern technologies make it possible to extract all gold, includ- ing its nanometer-sized particles regardless of their genesis. This approach to the problem discussed in this paper highlights the economic significance of newly fon:~ed supergene gold. GOLD MIGRATION. IN SUPERGENESIS ZONES Vernadsky [55] evaluated the average. gold concen- tration in riverine waters at 3 x 10-10%. Other research- ers [51 ] assayed this concentration in mine waters at 1 x 10-'to 9 x 10-x% [51]. Roslyakov et al. [56] deter- mined that the Au solubility in waters with Ca sulfate is higher than in waters with Mg sulfate: 4.27 and 2.65 µg/1, respectively. The pH of these waters varies from 6.5 to 8.0. The supergene concentration of gold. was demon- strated to be controlled by the occurrence of geochem- ical barriers, such as oxygen, reducing .(hydrogen sul- fide, sulfate, and. carbonate), alkaline, and acid, as well GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 GMC DATA REPORT 3 4 4 Page 46/117 Fig. S. Pseudomorphic replacement of magnesioludwigite crystals (Ld, dark gray) by tochilinite (To, black) and of pyr- rhotite (Po, white) by stringers of magnetite (Mg, pale gray). Zheleznyi Kryazh deposit.. Polished section, magnifi- cation 30". 166 ALEKSANDROV as the evaporation of mineralized waters in arid envi- ronments or in the presence of mineral adsorbents. Data on the role of heterotrophic microorganisms (bacteria) in the dissolution of gold particles and the later reduction of gold in the form of its newly formed masses are scarce [57]. Nevertheless, available infor- mation suggests that gold can be involved in the biolog- ical cycles of the bacteria, and this is associated with changes in the surface topography of native gold grains with the development of humps and pores whose sizes are commensurable with those of the microorganisms. The gold particles (0.1-0.2 mm across) used in the experiments lost half of their masses during experi- ments that lasted for one year, and the dissolved gold was reduced and occurred in the solutions in the form of very fine colloid particles. Their concentrations in the sols were 166 mg/1. The authors argue that gold oxi- dation and reduction proceeded concurrently, as fol- lows, for example, from the development of newly formed crystals, botryoidal aggregates, spongy masses, and lumps of newly formed gold on the surface of pri- mary gold particles. The fineness of this gold varies from 954 to 746, whereas the primary gold is 843 fine. Furthermore, gold migration (and reduction) is facilitated by the presence of organic fulvic acids in the waters and the biological activity of microorganisms (fungi and others). This phenomenon is reflected in gold precipitation from groundwaters by plants, for example, reindeer lichen and other species, as was repeatedly documented during the biogeochemical studies of gold ore fields, including their magnesian skarn types. ROLE OF CRYOGENESIS IN GOLD MIGRATION In the context of our research and with regard for the location of the deposits described in this publication in permafrost and seasonal freezing areas, we attach par- ticular significance to the cryogenic migration and regeneration of gold. Studying the hydrochemical effects of cryogenic .processes on the origin of aqueous solution flows dis- seminating gold, Plyusnin et al. [58] have demonstrated that gold concentrations in waters are usually equal to 6.6 x iir' gfi and increase to I1.2 x 10-' g/I in thawed waters and to 15.0 x 10-' g/1 in waters that were prelim- inarily frozen at a temperature of ~°C. The authors explain these differences by the unusual properties of thawed waters, which can dissolve more gold, but do not consider the possibility of gold regeneration. Fedoseeva [59] published data on gold migration in frozen soils and snow, a process controlled by the phys- icochenucal characteristics of ice surface and the prop- erties of intercrystalline liquidlike films. The presence of these films was identified within the temperature range of 0 to -10°C. It was demonstrated that Au and Cu are contained in the pore solutions in the form of ions that can form complex compounds. Gold can occur as dithousuilfate-curate, which is stable within a broad pH range and. can be readily reduced to the elementary form. The processes of permanent (seasonal) freezing of groundwaters in certain areas in Siberia, North Amer- ica,and other regions where the gold deposits discussed in this paper are situated should notably affect the con- centrations of dissolved gold. The freezing of water in the active soil stratum produces ice that contains prac- tically no dissolved salts, which are thus concentrated in the residual liquid contained between ice crystals. The gold concentrations in this liquid can increase by almost two orders of magnitude. This. creates favorable conditions for gold precipitation from these solutions on the surface of gold particles in placers or at the sur-. face of ice crystals. The occurrence of this process in nature is con- firmed by the finds of thin gold films between ice crys- tals at the Yellow Knife deposit in Canada [60]. The possible growth of gold dendrites from gold-oversatu- rated residual solutions during the seasonal freezing of the thawing stratum in placers in the Kolyma area was reported by Kolyasnikov [61 ], who believed that the morphology of these dendrites inherited the shapes of dendritic snow crystals and admitted that these den- drites could be overgrown by equant gold crystals and thus thickened to the sizes of normal flat gold particles. Kolyasnikov also believed that the gold potential of depleted placers in the Arctic can be naturally restored by the permanent regeneration of gold from periodi- cally freezing groundwaters of the active stratum. The role of cryogenesis in the migration and redepo- sition of native gold, including the mechanical trans- portand concentration of gold particles in soil polygons at the bottom of the active stratum during its seasonal freezing and thawing [62, 63] deserves more detailed study. The materials presented above generally character- ize the geochemistry of the evolutionary behavior of gold in the endogenic and supergene processes forming magnesian-skarn ore deposits. It was demonstrated that Fe and Cu hydroxisulfides (tochilinite and valleriite) are a previously unknown important link of the genetic mineralogy of gold. O~~r results can be used during the mining operations not only at contact-metasomatic (skarn) deposits but also at precious-metal deposits hosted in dolomites, carbonatites, and ultrabasites. The results of our research confirm the importance of and the necessity of studying the processes of gold regener- ation in supergenesis zones at ore deposits, placers, and the dumps of gold deposits. CONCLUSIONS 1. Magnesian skarn deposits of gold-bearing sulfide. ores are a promising source of this metal in the form of its primary lodes and spatially related alluvial and. other. types of placers. A common feature of these deposits is GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 GMC DATA REPORT 3 4 Q Page 47/117 GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 167 their spatial restriction to contacts of do}omites with intrusions of predominantly mafic composition or those of syenites, although this does not rule out the necessity of assaying the ore potential of skarns in contacts with granites and ultrabasites and in carbonatites. 2. Gold-bearing sulfides are contained at these deposits in pyroxene and forsterite skarns and calci- phyres, periclase marbles, dolomites, and magnetite- ludwigite ores, including overprinted calcic-skate associations. 3. Iron and copper sulfides contained in magnesian skarns are ubiquitously replaced by hydroxisulfides (tochilinite and valleriite) under the effect of hydrother- mal solutions. These hydroxisulfides inherit fine gold from the replaced sulfide. The hydroxisulfides are unstable and are endogenically replaced by magnetite and Cu, Fe, and Mg sulfates, and this facilitates the migration of readily dissolved fine Au and its regenera- tion on the surface of larger Au particles or in nearby rocks. In the zone of supergenesis, tochilinite and val- leriite are easily oxidized, and their gold is inherited by masses of magnetite dust and is partly adsorbed by iron and copper. hydroxides and/or is dissolved in meteoric waters. 4. The problem of the tochilinization and valleriiti- zation of sulfide ores is significant for genetically diverse deposits of copper and precious metals and is of great scientific and applied importance. This problem can be solved both by the improvement and mode~niza- tion of technologies of gold recovery and, perhaps, also PGE from ores and dumps and by the deciphering of the geochemistry of the supergene migration and regen- eration of native metals in placers. S. In permafrost areas, where several gold deposits occur in Russia and Canada, dissolved gold is concen- trated in the residual unfreezing liquid of the active stratum during its seasonal freezing and thawing. The gold concentration in the Iiquid can thereby increase by almost two orders of magnitude. The cryogenic con- centrating of gold-bearing solutions in intercrystalline liquid films. in ice can facilitate gold regeneration in placers on the surface of gold grains and particles or at adsorbents.. The permanent freezing of soils activates this process and can result in the restoration of the gold potential of depleted placers and mine dumps. ACKNOWLEDGMENTS The author thanks V.G. Senin (Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences) for microprobe analyses of sul- fides and Dr. T.C. Mowatt (United States Geological Survey) who provided us with his collection of skarns and ores from deposits of the Whitehorse copper belt in the Yukon Territory, Canada. REFERENCES 1. D. S. Korzhinskii, `A Sketch of Metasomatic Processes," in Mairt Problems in Studies of Magmatic Ore Deposits (Akad. Nauk SSSR, Moscow, 1955), pp. 334-456 [in Russian]. 2. S. M. Aleksandrov, V. L. Barsukov, and V. V. Shcherbina, Geochemistry of Endogenous Boron (Nauka, Moscow, 1968) [in Russian]. 3. S. M. Aleksandrov, "Self-Organization during the Pro- . grade Metasomatism of Carbonate Rocks," Geokhimiya, No. 9, 1323-1338 (1995), 4. N. A. Blokhina, Mineralogy, Geochemistry, and Forma- tion Conditions of Gold-Sulfrde Deposits in Magnesian Skarns (Central Tajikistan) (Donish, Dushanbe, 1984) [in Russian]. 5. S. M. Aleksandrov, Geochemistry of Skarn and Ore For- mation in Dolomites (Nauka, Moscow, 1990) [in Rus- sian). 6. V. L Kiselev and V. I_ Budanov, Precambrian Magee- . sian-Skarn. Deposits of the Southwestern Pamirs, (Donish, Dushanbe, 1986) [in Russian]. 7. V. A. Zhazikov, "Magmatic Replacement of Cazbonate Rocks," in Proceedings of 21 th International Geological Congress. Reports of Soviet Geologists. Granitic Gneisses, (AN SSSR, Kiev, 1960), pp. 66-79 [in Rus- sian]. 8. S. M. Aleksandrov, "Magnesian Skarn Deposits: Distri- bution and Facies," Geokhimiya, No. 5, 661-671 (1990)_ 9. G. E. Ray, I. C. L. Webster, and A. D. Ettlinger, "The Distribution of Skarns in British Columbia and the Chemistry and Ages of Their Related Plutonic Rocks," Econ. Geol. 90, 920-937 (1995). 10 11. 12. 13. 14. i5. 16. 17. 18. 19. GEOCHEMISTRY INTERNATIONAL VoI. 45 No. 2 2007 61V~ DATA REPORT 3 4 4 M. S. Kuchukova, M. I. Ismailov, and N. K. Dzhamalet- dinov, Skarn-Hosted Rare Metal and Pegmatite Deposits in Western .Uzbekistan (FAN, Tashkent, 1971) [in Rus- sian]. M. D. Skurskii, Interiors of Transbaikalia (Chita, 1996) [in Russian]. D. Tenney, "The Whitehorse Copper Belt: Mining, Exploration .and Geology (1967-1980)," Dept. Ind. North. Aff. Can. Geol. Sect. Bull., No. 1 (1981). L. D. Meinert, "Gold in Skarns of the Whitehorse Cop- per Belt Southern Yukon," Yukon Geol. Z, 19--43 (1986). S. D. Sher, Gold Metallogeny (North America, Australia, and Oceania) (Nedra, Moscow, 1972) [in Russian]. M. Ripa, "A Review of the Fe-Oxide Deposits of Bergslagen, Sweden and Their Connection to Au Miner- alization," in Mineral Deposits: Process to Processing, Vol. 2 (Balkema, Rotterdam, 1999), pp. 1349-1352. G. F. Smith, Physical Geochemistry (Addison, Wesley, Reading, 1963; Nedra, Moscow, 1968). S. M. Aleksandrov, "Quantitative Correlation between Compositions of Contact Magmatic Rocks and Adjacent Magnesian Skarns," Geokhimiya, No. 5, .641-651 (1992). S. M. Aleksandrov, `Assimilation of Metamorphic and Metasomatic Carbonate Rocks by Granitic Magmas," Geokhimiya, No. 11, 1398-1415 (1992). S. M. Aleksandrov, "Formation of Skazns after Dolo- mites at the Contacts with Granitic Magma," Geokhimiya, No. 6, 801-820 (1993). Page 48/117 168 ALEKSANDROV 20. W Petruk, D. C. Harris, and E. J. Mutray, `An Occur- rence of Valleriite from New Imperial Mine, Yukon," Can. Mineral. 10, 885-888 (1971). 21. K. Harada, K. Nakao, and K. Nagashima, "Valleriite from Little Chief Mine, Whitehorse Copper Belt, Yukon, Canada," Mineral. J. 7, 221-227 (1973). 22. L. I. Shabynin, Association of Magnesian Skarns (Nauka, Moscow, 1973) [in Russian]. 23. S. M. Aleksandrov, "Genesis. and Mineralogy of Calc Skarns of the Prograde and Retrograde Metasomatic Stages," Geokhimiya, No. 3, 281-297 (2002) [Geochem. Int. 40, 244-259 (2002)]. 24. S. M. Aleksandrov, "Metasomatic Alteration of Carbon- ateRocks at the Contact with Basic and Uluabasic Intru- sions," Geokhimiya, No. $, 1218-1238 (1985). 25. D. M. Turovtsev, S. F Sluzhenikin, S. K. Mikhalev, et al., "High-Temperature Contact Metamorphism of the Car- bonate Rocks in the Aureoles of Norilsk Basic-Ultraba- sic Intrusions," Rudy Mei., No. 5, 57-65 (2002). 26. E. V. Kislov, The Ioko-Dovyren Layered Pluton (Buryat. Nauchn. Tsentr Sib. Otd. Ross. Akad. Nauk, Ulan-Ude, 1998) [in Russian]. 27. N. N. Pertsev, E. G. Konnikov, E. V. Kislov, et al., "Mer- winite-Facies Magnesian Skarns in Xenoliths from Dun- ite of the Dovyren Layered Intrusion," Petrologiya 11, 512-523 (2003) [Petrology 11, 464-475 (2003)]. 28. S. M. Aleksandrov and V. G. Senin, "Genesis, Composi- tion, and. Evolution of Sulfide Mineralization in Magne- sian Skarns," Geokhimiya, No. 6,614-633 (2005) [Geochem. Int. 43, 559-577 (2005)]. 29. D. A. Dodin, N. M_ Chernyshov, and B. A. Yatskevich, PGE Deposits of Russia (Nauka, S[. Petersburg, 2000) [in Russian). 30. G. Yu. Ivanyuk, V. N. Yakovenchuk, and. Ya. I. Pakho- movskii, Kovdor,. (Mineraly Laplanii, 2002) [in Rus- sian]. 31. Palabora Mining Co Ltd. Mine Geology and Mineralogy Staff, "The Geology and the Economic Deposit of Cop- per, Iron and Vermiculite in the Palabora Igneous Com- plex: ABrief Review," Econ. Geol. 71, 177-192 (1976). 32. L. A. D. Menezes, Jr., "The Jacupiranga Mine, Sao Paulo, Brazil," Mineral. Rec. 15, 261-270 (1984). 33. A. C. Moore, "Orbicular Rhythmic Layering in the Pal- abora Carbonatite, South Africa," Geol. Mag. 121, 53-60 (1984). 34. I. P. Laputina, `Mixed-Layer Sulfide-Hydroxide," in Micro- probe in Mineralogy (,Nauka, Moscow, 1991), pp. 92-93 [in Russian]. 35. N. I. Organova, A. D_ Genkin, A. L. Dmitrik, et al., "Structure and Isomorphism of the Valleriite Group," in Isomorphism in Minerals (Nauka, Moscow, 1975), pp. 150-162 [in Russian]. 36. N. I. Organova, A. D. Genkin, V. A. Drits, et al., "Tochi- linite: ANew Sulfide-Hydroxide of Iron and Magne- sium," Zap. Vses. Mineral. O-va 100, 477-487 (1971). 37. P. O. Ramdohr, `A Widespread Ore Mineral Paragenesis Related to Serpentinization," Geol. Rudn. Mestorozhd, No. 2, 323 (1967). 38. E. H. Schot, J. Ottemann, and P. Omenetto, "Some New Observations on Mackinawite and Valleriite," Rend. Soc. Ital. Mineral. Petrol. 28, 241-295 (]972)_ 39. S. M. Aleksandrov, "Genesis and Composition of Borate and Sulfide Mineralization in the Mount Jumbo Dunite, Snohomish County, Washington, United States," Geokhimiya, No. 3, 312-326 (2005) [Geochem. Int. 43, 277-289 (2005)). 40. S. M. Aleksandrov and V. G. Senin, "Genesis and Prod- ucts of Is;eplacement of Tochilinite and Valleriite in Sul- . fide-Bearing Borate Ores of Magnesian Skarn Deposits," Geochem. Int. 39 (SuppL 2), 181-193 (2001). 41. N. J. Cook and C. L. Ciobanu, "Paragenesis of Cu-Fe Ores from Ocna De Fier-Dognecea (Ronania), Typifying Fluid Plume Mineralization in Proximal Skarn Setting," Mineral. Mag. 65, 351 372 (2001). 42. T. Watanabe, "Geology and Mineralization of the Suian District, Tyosen (Korea)," J. Fac. Sci. Hokkaido Imp. Univ. Ser. IV Geoi. Mineral. 6 (3-4), 207-303 (1943). 43. S. M. Aleksandrov and M. A. Troneva, "Genesis and. Composition of Boraces of the Ludwigite-Vonsenite Series in Magnesian Skarns of the Urals, Siberia, and the Russian Far East," Geokhimiya 42, 525-543 (2004) [Geochem. Int. 42, 44964 (2004)]. 44. S. M. Aleksandrov and M. A. Troneva, "Genesis and Composition of Ludwigite-Vonsenite Borate Series in Magnesian Skarn of Central and East Asia," Geo- khimiya 42, 992-1011 (2004) [Geochem. Int. 42, 870-886 (2004)]. 45. A. E Korobeinikov and V N. Sanin, "Precious Metals at Magnetite Skarn Deposits of the Kaz and Sukharinskii Ore Fields in Gornaya Shoriya, Russia," Geokhimiya 42, 419-431 (2004) [Geochem. Int. 42, 352-363 (2004)). 46. C. L. Ciobanu, N. J. Cook, and H. Stein, "Regional Set- ting and Geochronology of the Late Cretaceous Banatitic Magmatic and Metallogenetic Belt," Miner. Deposita 37, 541-567 (2002). 47. S. M. Aleksandrov, Geochemistry of Boron and Tin in Magnesian Skarn Deposits (Nauka, Moscow, 1982) [in RussianJ. 48. V. E. Kunilov, F. I. Stekhin, and G. A. Mitenkov, "Effect of Natural Features of Valleriitization of Cupriferous Ores on Copper and Nickel Extraction," Tsvetn. Met., No. 2, 114-116 (1989).. 49. N. V. Petrovskaya, Native Tin (Nauka, Moscow, 1973) [in Russian]. 50. L. A. Nikolaeva, "New Gold in the Lena Area Placer," Tr. TsNGRI 25, l I9-122 (1958). 51. S. V. Yablokova, "Formation of New Gold in Some Plac- ers of Southern Yakutia," in Geology of Placers (Nauka, Moscow, .1965), pp. 152-155 [in Russian]. 52. M. I. Novgorodova, M. E. Generalov, and N. V. Trubkin, "New Gold in the Residuals of the Southern Urals (Rus- sia)," Geol. Rudn. Mestorozhd. 37 (1), 40-53 (1995). 53. F. W. Freise, "The Transportation of Gold by Organic Underground SoIutions," Econ. Geol. 26, 421--431 (1931). 54. D. V. Voronin and I. S. Goldberg, "Electrochemical Pro- cesses in the Placer Deposits of Native Metals," Dokl. Akad. Nauk SSSR 207, 190-192 (1972). 55. V. I. Vernadsky, Selected Works (Nauka, Moscow, 1955) [in Russian]. Ili-1~ r}aT~ REPORT 3 Q 4 GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 Page 49/117 ~. i f GOLD BEHAVIOR DURING ENDOGENIC AND SUPERGENE ALTERATIONS 169 56. N. A. Roslyakov, V. V. Polikarpochkin, G. V. Nesterenko, et al., "Conditions of Supergene Migration and Accumu- lation of Gold," Geol. Geofiz., No. 7, 99-108 (1977). 57. E. D. Korobushkina and I. M. Korobushkin, "Interaction of Gold with Bacteria and Formation of New Gold", Dokl. Akad. Nauk SSSR 287, 978-980.(1986). 58. A. M. Plyusnin, Yu. F. Pogrebnyak, and E. M. Tat'yan- kina, "Effect of Cryogenic Processes on the Formation of Aqueous Flows of Scattered Gold," Dokl. Akad. Nauk SSSR 247, 700-703 (1979). 59. V. I. Fedoseeva, Extended Abstract of Doctoral Disserta- tion in Chemistry (Tomsk, 2000). GEOCHEMISTRY INTERNATIONAL Vol. 45 No. 2 2007 GI~C DATA REPORT 3 4 4 60. R. W. Boyce, `An Occurrence of Native Gold in An Ice Lens: Giant-Yellowknife Gold Mines, Yellow-Knife, Northwest Territories," Econ. Geol: 46, 223-227 (1957). 61. Yu. A. Kolyasnikov, "Mystery of Gold Dendrites," Kolym. Vesti, No. 11, 42 (2000). 62. V. G. Nemchinov, "Mechanism of Native Gold Migra- tion in the Active Layer of the Cryogenic Zone as Exem- plified by the Pionerskoe Gold Deposit, Eastern Sayan," Metally Rudy, No. 3, 67-70 (1999). 63. R. A. Amosov, "Cryogenic Recrystallization and Mech- anisms of Authigenic Gold Accumulation in Placers and Residues," in Natural and Anthropogenic Placer Depos- its of Residuals at the Turn of Millennium (Moscow, 2000), pp. 18-20 [in Russian. Page 50/117 A Comprehensive Journal Covering All Multidisciplinary Aspects of Theoretical and Applied Geochemistry, Cosmochemistry, Organic Chemistry and Chemistry of Environment 4 r ~ A P C ~- MAVIK "HAYKA/INTERPERIODICA" 1 N A Pleiades Publishing A U B i Distributed by ~ S rin er° _ p g GMC DATA REPORT 3 4 4 Page 51 / 117 ~: Contents Vol. 45, No. 2, 2007 Simultaneous English language translation of the journal is available from Pleiades Publishing, Ltd. Distributed worldwide by Springer. Geochemistr~• Intenuztiorutl JSSN 0016-7029. Volatiles in Basaltic Magmas of Ocean Islands and Their Mantle Sources: I. Melt Compositions Deduced from Melt Inclusions and Glasses in the Rocks V. L Kovalenko, V. B. Naumov. A. V. Girnis, V. A. Dorofeeva, arul V. V. Yarmolyuk 105 Petrochemical Systematics of Amphibolites from the Archean Section of the Kola Superdeep Borehole N. E. Kozloi; E. V. Martynot; N. E. Kozlova, T. V Kaulina, and Yu. P. Smintov 123 Composition of Rock-Forming Minerals in the Kivakka Layered Massif, Northern Karelia, and Systematic Variations in the Chemistries of Minerals in the Rhythmic Layering Subzone Ya. V Bychkova, E. V. Koptev-Dvorrtikoi; N. N. Kononkava, attd E. E. Kamerteva l 31 Gold Behavior during EndoQenic and Supergene Alterations of Sulfides in Magnesian Skarns ~ S. M. Aleksandrov Mercury. in the Sedimentary Deposits of Lake Baikal 152 V, F. Gelet}; G. V. Kalmykov, and !. Yu. Parkhomenko 170 Interaction of Cr(III) with the Humus Acids of Soil, Water, and Bottom Sediments I. Ya. Koshcheeva, S. D- Khushvakhtova, V. V. Levinskii, V. N. Danilova, a,td Yu. V. Kholin 178 Distribution of Metals in Bottom Deposits in the Branches of Selenga River Delta Z 1. Khazheeva and A. K. Tulokhonov 185 Short Communications "Pseudocyclicity" as a Result of Random Events with Reference to the Rhythmic Layering of Magmatic Complexes A. A. Yaroshevskii 193 Age of the Magmatic and Metamorphic Processes in the Vodtozero Complex, Baltic Shield: An Ion Microprobe (SHRIMP II) U-Th-Pb Isotopic Study of Zircons S. A. Sergeev, E. V. Bibikova, D. I. Matukot; and S. B. Lobach-Zhuchereko 198 Heat Capacity and Thermodynamic Functions of Epsomite MgSO4. 7 H2O at 0-303 K V. M. Gurevich, O. L Kuskov, K. S. Gavrichev, and A. V. Tyurirt 2Of Gl'~I~ GAin ~rP~RT 3 4 4 Page .52/117 PART 2: DATA SUPPLEMENT TO: INVESTIGATIONS OF SOME MINERALOGICAL, PETROLOGICAL, GEOCHEMICAL, AND GEOLOGICAL RELATIONSHIPS AT THE ARCTIC CHIEF (WEST) LOCALITY, WHITEHORSE COPPER BELT, YUKON TERRITORY, CANADA Thomas C. Mowatt (1) June C. Mowatt (2) June 6, 2007 (1) Geologist, and Senior Associate, On-Line Exploration Services Inc., Anchorage, Alaska; c/o Post Office Box 1438, Haines, Alaska 99827 USA (2) Geologist (Deceased, 1992) Part 2 of this report, the °Data Supplement° addendum, is attached below. This presents additional information, including sketch maps showing general locations of sample. sites, abstracted field notes, results of 30x/80x stereo-microscope examination of samples, petrographic microscope examination of selected materials as grains-in-oil, .analyses and other comments by TCM. 6l~C DA A REPORT 3 4 4 Page 53/117 SKETCIi MAPS OF SAMPLE LOCATIONS (Zt}U4-2Q06), ARCTIC CHIEF, WHITEHORSE COPPER BELT YUKON TERRITORY CANADA: Three sketch maps follow. Labelled "Page 1 of 3", "Page 2 of 3°, "Page 3 of 3". They are not drawn to scale lie. "cartoons°). .Each map depicting, variously, the locations from which sample materials discussed in this report were obtained. The numbers, and/or letters, representing. such locations on these maps are those referenced elsewhere (above) in the present report, as well as in the condensed/abstracted field notes, and the initial analyses resulting from the preliminary ° n x mi e a nati~n!»tnaym~ ~f specimens, which make up the two sections of "supplemental data , below, comprising the remainder of this report. GMC DATA REPORT 3 4 4 Page 54/117 ~'~ ~,~ v Z Q ~ ti' ~ \~ U ~ ~ V ~ Q v ~ ~ ~'~ -Rt V .o ~ ~NiC DATA REPORT 3 q 4 Page 55/i17 i ~ ~~'~ UA 1 ~i ~~~~~ 1 3 4 4 Page 5 6/.117 ~~ c~ - -- \~. ~~ \ ~ ~'~ v ~=~~._ 4 ~. l ~- ~ O ~ ~~ ~ ~ ~ 1 ~ ~ ~ ~ ~ t r ~ O ~ j ~D a ~ ~~ -~ ~ ~ ~ ,~ ~~ ~ `~ a. t ~. ~~ ~ .~ -~ % \ ,~ ~ `, / ~. ~ ~ ~ ~~ ~ f~ 1 << i 4 i t fit! s ~~ ~ ~ /f l ~ 1 :~ E '~ - ~--- ~~ ~ liuii, UHiA REPORT 3 4 4 Page 5~/1~ ~. ~.. C?i ~~ FIELD NOTES/COMMENTS ON SAMPLES COLLECTED AT THE ARCTIC CHIEF ("AC") LOCALITY (TCM): The sample labeling scheme used is exemplified as follows: TM =sampler's initials; "04" _ the year, 2004; "6" =the sixth month, June; "9" =the ninth day of that month; "3" =the sample locality/site for that day, per the field notes; the final number.. ("N") is that assigned to a/this particular specimen. fe., in this instance: [TM-04-6-9-3-N]. Sample locations are shown on the sketch maps ("Pages 1 of 3, 2 of 3, 3 ®f 3 ")above. FIELD NOTES, 9 JUNE 2004--- 9 June 04- 1- Character samples (carbonate rocks -- [apparently "marbles, calciphyres"]--, "skarn" materials, "ores") from rubble-crop/rubble. Note some "brownish specks" (perhaps brucite, after perclase?) in some of the carbonate rocks? Locality is on the "north" rim of the mined-out pit (the "west pit", .the larger of the two pits at the Arctic Chief}. The other ("east pit") is lower down the hillside, to the south and east of the larger pit, and features "granitic" .rocks at the western end. 2- No .samples thus labelled. [TM-04-6-9-1 ](Map# B1) 3- Just southeast of locality #1. "AC (west}" pit, along "north" rim, just above the entrance to the pit. Samples in-place, or immediately below pit-margin outcrops/exposures, "tricky" to work on alone. Carbonate rocks ("marbles") immediately adjacent to "skarn" materials +/"calciphyre(s)"?, /+/-?. The skarn here appears to occur as an (originally igneous?) apophysis/projection/finger/lens-like mass into/within the carbonates.. Analogous to a "crushed zone" setting? Note some "brownish specks" (perhaps brucite, after. perclase?) in some of the carbonate rocks? Presumably. the "igneous?"-appearing rocks here are - or are related to -those termed in the literature as "mafic dike[s]"? As observed here: porphyritic (light buff-colored phenocrysts of altered plagioclase, +/-), with green-grey fine-grained matrix. These rocks are hard ("ringing"-"bell-banging" when hammered, with sharp-edged fragments}, and are in evidence as apparent rubble-crop/rubble(?) here. Might these so-called dikes actually represent marginal portionsloffshoots/border zoned"chills"/rapidly-cooled variants of the (contaminated/"basification" by assimilation/reaction with intruded rocks/carbonates) ' [cf. TM-04-6-9-3(?)-2, an apparent "plagioclase - pyroxene" rock of interesting "salt-and-pepper" aspect/possibly igneous texture??] "main (granodioritic/granitic?) magman responsible (thermally and geochemtcally) for the bulk of the metamorphism/metasomatism at the AC?? Are these "dike" rocks and/or the/any other "skarn" rocks here at this sample ' site/locality at least in part "endaskarn", at least in a certain sense/one sense or another?? Fine grained/porphyritic, rapidly-cooled/quenched variants of a "dioritic"/more mafic magmatic type. (with plagioclase[?] phenocrysts having formed initially during ~basificatton" 1-F GMC DATA REPORT 3 4 4 Page 58/1ll of the main magma, at the periphery of the main intrusive body, and "quenching" of the matrix subsequently during injection into country rocks as "basified" magma at elevated temperatures?? With perhaps some, or perhaps relatively littlelnone metamorphic/metasomatic effects [even at the relatively high temperatures likely extant, due to the relatively small volume of these melt materials as well as perhaps the physical. conditions leading tolpermitting their migrationlintrusion into the country rocks] on adjacent surrounding country rocks into which this partially crystallized mafie melt was intruded??) ?? [le. relatively rapid. intrusion, perhaps due to tectonic activitylfracturing of country rocks, with attendant pressure drop/release, .cooling, etc. ??} Perhaps aided and abetted in their distribution,. emplacement, cooling and solidification by structural/tectonic eventslfeatures, in particular fractureslfracture zones, perhaps related to the "contraction phenomenonA associated with the evolution of the main magma body(ies), as. discussed/espoused by Aleksandrov?? [ie. perhaps representatives of the "main magma" extant at depth subsequent to the metamorphic and metasomatic events/conditions: attendant to the formation of the skarns and related mineralization??]. "Long-livedn (or perhaps only relatively short-lived} tectonic "crush zones", ie. Featuring/afford'+ng porous and permeable zones, reduced pressures, locally andlor for. relatively brief periods of time, perhaps facilitating migration/ "flight"/escape of more .basic/less silicic, higher temperature, lower viscosity melt materials as "fugitives", in a sense, from the bulk heat source of the main magma body?? With or without assistance from tectonic manifestations related to physical differences in main magma body versus surrounding rocks, in addition to heat differentials>gradients. is the somewhat casual/summary treatment/dismissal of these "dikes", especially in terms of their influencelrelevancelsignificance with regard to the metamorphism-metasomatism- mineralization, as mentionedlindicated/suggested in ~reviotts reports, perhaps mis- guided/inappropriatelshort-sighted/premature??? A NOTIC?Nfl-HREAD PERHAPS WORTH LOQKING INTO FURTHER. Cf. (below, locality #4) photos from opposite ("southfl) rim of pit, featuring views of locality #3. [TM-Q4-6-~-3] (Map #3) 4- Just across the AC (west) pit entrance from locality #3, to the south-"ish". Samples and photos looking. northward at locality #3, and around the pit to the. west. Samples of carbonate rocks ("marbles", and "calciphyres~), "skarn materials, "ores; in-placelrubble-crap. Note some "brownish specks {perhaps brucite, after. perclase?) in someo# the carbonate rocks? Note interesting structures in the carbonate rocks and associated skarh materials (across pit entrance) as shown in these photos. ~Tnn-u~-5-~-~j (iuiap #~) 5- Just "east" of locality #3, on northeast side of AC {west) pit. Outcrop and subcrop carbonate rock samples ("marbles", and "calciphyres~); rubble-crop?/rubble samples of "skarny materials, "ores", "endoskarnldiorite" material(?). Note some "brownish specks" (perhaps brucite, after perclase?) in some of the carbonate rocks? [TM-04-6-9-5j (Mega #5} C- Today also. collected grablcharacter samples of rubble from along the road downhill east of the AC {west} pit. Samples likely came from the "AC a st}n pit. Samples taken at 2-F ~~IiG O~TA REPORT 3 4 4 Page 59/11 easternmost end ofi the smaller pit area, along a shoulder on the north side at the open end of the cut (ie. the end distal .from the pit "headwaii~) into. the pit proper. Several photos into pit, with "granitics",-~1- (?), at the tar endlheadwali of the AC (east) pit. FiEL.D N®TES, 't0 JUNE 2004--- Photos of Arctic Chief (east) pit. Fcom about the TM-04-6-g-6 iocaie. Photos ofi AC (west) pit. From both the TM-04-6-9-f and ~ locales, as well as the TM-04- 6-g-4 locale. 1l) June 04- 1- Below iocaie S June 04-3 [TM-04-6-9-3j, rim of AC (west} pit. Samples of "skarn" materials,. carbonate rocks {"marbles", and "calciphyres"; brownish specks, perhaps brucite ,after periciase, noted in many of these}, as well as "dike. rocks"{??}..Rubble immediately below .the semi-intact outcroplexposure hanging overhead, as weii as jutting out over the edge of the pit wall (a "dicey" sampling spot --- "not a piece to spend the night"}. Cf. remarks under entry "9 June 04-3", above. Cf. numerous photos. [TM-Q4-6-'1Q-1~(Map #3) 2- A variety of "character" samples from rubble near entrance to AG {west) pit. Most not far from their apparent in-place sources just uphill; others mare likely are appreciably out-of- place, from elsewhere inside the pit, moved and deposited here by activities during the course of developing the pit, etc. 3- Additional samples from near J June 04-5 locality (which ct.). [TM-04-6-1Ef-3](Map #13) Next opted to search for carbonate rocks of more "original" naturelcharacter, ie. {hopefully} outside the sphere of influence of the intrusives, rocks at least of "less-than-marble-grade". Drove on up the road beyond the north side of the top of the AC {west) pit; went a couple of miles, with fair but intermittent rack exposures, apparently of igneous/"granitic- dioritic"Imetamorphic? character. (Perhapsliikeiy it would be more fruitful to pursue 'unbesrnirchedfuntainted", hopefully stratigraphicaliy at least somewhat "equivaien#" carbonate rocks along strike to the "north- northwest" (or, perhaps, across the entrance to the AC (west). pit, into and beyond the carbonate rocks exposed at the rim of the pit on that /"south Side; ie. at the 04-6~9-4 iocaie and along its trend}. Cf. the striking mountainside (cf. photo #"36n) exposures some distance to the north of the AC. Need to check with Mike Burke on this. Although the exposures along the entrance cut of the "east" pit at AC might well have the sorts of °precursoriai" carbonate rocks I'm looking for[?J.). 3-F Gt~i i~~~~~i REPORT 3 4 4 Page 6o/il~ 4- Outcrop ("4a° sample locality; "skarn° materials) along the road at odometer reading 184.7, on uphill beyond the top of the. AC (west) pit. Other samples here include a piece of float/subcrop/rubblecrop (perhaps .even road-building/bulldozer-relocated -- if so, from uphill, presumably/mast likely??-- and redeposited material?) of "skarn"I"dioritic"? (hornblende-bearing?) rock taken from the "southern" side of the road, displaying appreciable amounts of moybdenite on fracture surfaces of broken sample {cf. HAT "new- type" mineralization??}. The outcrop at this locality crosses .the road, with evident "skarn" featuring calcite, red-brown garnet, etc. [3M-04-fi-10-4](Map# Z/14) 5- Odometer = 184.7+++. Outcrop; featuring appreciable amount of sulphides?) - "pyrite?/pyrrhoYrte??/arsenopyrite"??? on fracture. surfaces of broken "diorite' specimen {cf. HAT "new-type" mineralization??}. Outcrop on the "northern" side of the road. [TM-04-fi-10-5j(Map# Z/15) 6- Odometer reading 184.9. Outcrop at dip in the road, just N/VV of the top of the AC (west) pit. Rocks are "dioritic°?; "endoskarn"??. Darker sample is from outcrop, fighter one. is "float"/not actually in place. [TM-04-fi-10-fi](Map# Z/1fi) 7- Odometer reading 185.0. Outcrop at the junction with .the road out to the top edge of the north rim of the AC (west) pit. Sample of "skarn" (endo?/exo?) materials, with .garnet veinlets, etc. [TM-04-fi-10-7](Map# 2117) 8- Same locality as 9 June 04-3 (which cf.). Photos of pit. Samples of carbonate rocks, skarn(s). [TM-04-fi-10-8](Map# Z/18) 9- Same locality as 9 June 04-5 (which cf.). Photos of pit. Samples of carbonate rocks, skarn(s). [TM-04-6-10-9](Map# Z/19} X- Ended the day's efforts at the Arctic Chief by taking a number of "serendipitous" grab/rubble/character/"doorstop°/"exploration" samples from here and there ("targets of opportunitya) along/beside the road from the north/east(?) edge of the AC (west) pit, which extends "northward" to its junction with the road leading up the hill [TM-04-fi-10-X](Map# "Z") (End field notes, June 2004) FIELD NOTES, 9 August 2004--- Arctic Chief (west) Photos from~NE~ rim of pit, into pit. "Sunrise" shots all around. View from TM-04-6-9- 1 &3 localities. (Map #s 1 &3). 9 August 04- 4-F GMC UATA REPORT. 3 q 4 Page 61 / 117 ~ - Samples from TM-rJ4-6-9-3 iocaie. "Dike" rocks, etc. vs. °hard" carbonate rocks. "Contact" between "skarn°/"carbonate" rocks? "Dikes" _ "plagioclase-pyroxene" rocks of SMA? Cf. photos across. pit mouth (poking toward iocaie. "5". These "dikes" appear possibly {in photos taken from TM-04-6-9-4 iocaie) to be associated with (?) "tongues° of "skarnlintrusive rocks (?) into the carbonates (?). 2 - Collected (as rubble/rubble-crap) four large bags ofi "typical" (?!) garnet-pyroxene +/- skarn "specimens" along the road from the north rim of the pit ---> read leading up the hill [TM-04-8-3-2] (Map # °`Z") Traversedltoured the "southeast<-->southwest" rimslupper benches ofi the AC (west). Many pho#os from there, and from the pit entrance, as well as from the "north-northeast" rim "carbonate" rocks locales. Did some "sketch mapping°, via pacing and Brunton compass. Noted no "granitics" at the "east<--->south" and "south<--->west" rims of the AC (west} pit during my approximately "3/4 of the way around" traverse/tour of the accessible portion of that area. Seems to be ail garnet-pyroxene, +l- "skarnU rocks thereabouts (?). [[PLAIN TO REVISIT[] Collected a number of samples {prpbabiyllikely as rubble-crop} pfi "typical" (?!) pyroxene- garnet, +/-, skarn", from the topl"bench" and edge of the "southwest" (Map# E), and "southeast" rims (Map #2~) of the AC (west) pit. Also collected samples of "ores° -same banded, from the "easternmost" part ofi the "southeast" rim). This traverse/"tour" also included the "southn ("headwall") rim of the AC (east} pit area, including photos. Note "granitics" (porphyritic--very fine grain--fine grain--coarser- grained; some containing -- mostly "maficA -- xenoliths) in rubble above this rim. ((PLAIN TO REVISIT]] (Map# F, ~ #23[partj). 12 Octaber 2004- Arctic Chief area. Windy and a bit chilly this morning up on the AC. ice on the windshield, etc., down in the valley at Whitehorse this morning. [TM-04-10-Y2-1-1 --->1 Collected "ores" (ie. magnetite +!- bornite +/- chaicopyrite +!- ?) from the AC (west pit entrance, and on inside pit (Map #22~), as well as uphill (Map. #22A) on south side of the pit entrance (in approximately the TM-6-9-4 area).. Rubbielfloat samples. Some samples frozen in place. Several "non-ore" specimens of "skarnp-materials, etc. {from below the TM-04-6-8-3 area; Map #22) . 5 - F Page 62/117 GMC DATA REPORT 3 4 4 ~rM-04-iQ-12-2-~ --->.~~ Below, approximately east-northeast, of the TM-04-6-9-4 locate, in the area peripheral to the "head» of the AC (east] pit. Rubble/float samples of "granitics», "ores". (Map #23}. Left the rather .impressive moiybdenite-laden "foot speeimen» of TM-04-6-10-4 `B» (Map # Z } with Jim Coyne for his continued edification/amusement, +{-possible slabbing to cook at vein-alteration-host rock characteristics. As R. Zuran put it, examining a piece,. "that's a lot of molt'»...... ------------------------------------------------------------------ ------------------------------------------------------------------ END OF 2004 FEELD SEASON FIELD NOTES. May & June 2005 -1 25 MaX 2005- Arctic Chief (west) Photos from "NE" corner (Map#s "®", "C"} of rim of pit. Views from, in, at and around the TM-04-6-9-1, &3, &5 localities. TM-05-5-25~ e: to-place and "recognizably-displaced" samples from TM-04-6-9-3 locate (Map area #C/Map area #3). "Dike» rocks, etc., vs. "hard» carbonate rocks. "Contact» between "dike"f"skarn»(?)/"carbonate» .rocks. "Speculatively»: These "dikes" appear (cf. photos from TM-04-6-9-4 locale) to perhaps (???) be"tongues» related to{of "skarn/intrusive rocks" (??) into the carbonates (?). Or, rather,"merely» dikes from magma intruded either{or/all (??) prior{durin~fsubsequent to the "main magma» events?) which were responsible for the formation (viz. metamorphism and metasomattsm) of the skarns and ore mineralization. EOr, rather, both/alt of these (???)~, Samples represent outcrop/"in-piace»{rubble-crop materials, either in-place or not at all far from being actually in-place. Many of these specimens were obtained in-place, at some varying degrees of hazard, from the very "brink'' of the (overhanging) ..pit rim. Specimens of carbonate rocks ("marbles", and "caiciphyres"; brownish specks, perhaps brucite after periclase, noted in many of these); porphyritic as welt as more equigranular ("dioritic»?) igneous (?) rocks (this locality is at the "massive" exposure, Trot the "bird»exposure; cf. photos and legends, 2004); "skarns materials (with some magnetite (?), +/-). Some examples of "lenses/zones" featuring .garnet, pyroxene, magnetite {?), +/- adjacent to carbonate host rocks. (Same photos of latter occurrences). These rocks occur in a three-part (or more} sequence, from {from "left to right»/"southish» to "northish»; cf. photos}: the "igneous»f"dike" rocks, through a "black" material interval, and thence into whitish{sight grey. carbonate rocks. 6-F Gt~C DATA REPORT 3 ~ 4 Page 63/11 As can be discerned on some of the photos taken, the site of TM-05-5-25-1 shows an interesting relationship between the darkish-light grey-light grey-greenish "dike" (?) rocks exposed in the "massive exposure" atop this locality and the adjoining carbonate rocks. At least in places, a "zone~f"lenses" (?} of very dark greenfblack materials?} occurs. between these "porphyritic and more-equigranular igneous" rocks and the. light greylwhitish carbonate rocks... There is somefa fair. amount of smaller-scale "intermingling between adjacent "zones" of this sequence {cf. samples). Some interesting structuresftextures ara manifest in some of these specimens. The "black" interval appears megascopicaflylfrom a distance to perhaps represent at least in part a "sheared" interval (with apparent siickensides, etc. noted on closer examination, in p(aces). The "blackish" material appears at least in part to be chlorite Speculative "scenariosn for .this particular locality might include: 1. "Black" materialfzone = a zone of sheaNcatactastic materialsfgouge, resulting from structural movement and attendant deformation along the dikefcarbonate r©cks contact zone subsequent to solidifiication of the dike rocks {with similar possible scenarios as suggested in #2; be[ow, as to the natureftiming/sequence of metamorphic andfor metasomatic effectsfevents (?). 2. "Blacks. material/zone =contact metamorphicfinetasomatic product{s) of dike magma intrusive into the carbonate rocks {the carbonates either previously unmetamorphosedfmetamorphosed-metasomatizedfaffected by "skarning" event(s)/processes, prior to intrusion of dike magma {?). 3. "Dike" magma coeval with, or an apophysis of, the "main magma" which was responsible for the overall contact metamorphismfinetasomatism of this depositflocality. Or subsequent to this? Or prior to this? Perhaps, as a guessfimpressionf"interpretations, the dike magma is {?) an offshoot of the main magma, from the relationships observed at this locale in particular. Some other observations at this locale ("Map #C") seem worthy of note as we!!: A. Same distance firom this Vantage point, in an .approximately northwest direction, apparent grey-green rocksfmaterials can be observed to occur at and near the top of the "steeply- dipping" sheer-faced "Northfl wail of the pit. These grey-green rocksfmaterials might well be "on trend" with the "massive exposures (ie. at locate "Map #r/") andfor "the bird" dike rock (also grey-green in aspect) exposures (at the "NE" pit corner rim area, on the "N" side of the pit entrance, respectively [ef. 2004 photos, as well as photos taken this date]). Or, these grey-green rocks near and at the top of the "N9 pit wall might (?), alternatively, be a continuation (across the pit, ie.) of a possible (?} dikefintrusion exposed in the the "S- SE" wail of the pit, adjacent to the carbonate rocks tf- of locate Map. #4. (This possible [?j dikefintrusion in the "S-SEn watt of the -pit is the "V-shaped° feature, with reddish margins, shown in photographs ]2004, 2005] from the "N-NE" rim ofi the pit, looking. approximately South.) B. Also note photos of the above-described "V-shaped" feature in the "S-SE° wall, as taken from the "NE" corner area on 25 May 2005. Note especially those featuring the .carbonate rocks of Map #5, with the "on-trend"/equivalent (?) carbonate rocks ofi Map #4 in the distance across the pit entrance, with the "V-shapedn #eature to the west of the carbonates, in the "S-SE" wall of the pit. C. Need to revisitfcheckfsample the rim above this "V-shapedA feature, as weft as the pit below it. Unfortunately the steepfessentialty vertical pit wall itself, further threatened/endangered by its overhanging rim, is not readily accesstbtefsarnpled in-place. 7-F GMC DATA REPORT 3 4 4 Page 64/117 Also took other photos from site "Map #Cn (and of the site itself as well). T M-05-5-25-2: Samples (two) from outcrop/in-place of the "steeply-dipping" sheer-faced "northeast" pit wall .near Map# "Ofl locale. "Pyritic siltstone" unit (?), or ??. Also several photos from this site. TM-05-5-25-3: Also collected a number of garnet-pyroxene +/- samples from the road from the north rim of the pit <---> road up the hill (the areas of Map#s "O" <--> "Z"). "F1oat-rubble" materials/"character samples". "Exploration samples". One never knows what might be lurking inside these (or any) types of rocks. As I (earned way back when....... Other photographs taken from Map # 5, #1, etc., from this general area of the "NE" corner of the pit rim. 26 June 2005- ARCTIC CHIEF (west)--- - 1 Character samples ("-A") from "Map #3" locale- :magnetite +/-. Character samples ("-B") from the northwest side of the pit entrance: magnetite, +/-. [TM-05-6-26-1-A, B~ NOTES: View of AC (east) pit, from AC (west) pit entrance :Sketch in notebook. Accompanied by D. Hogarth. END OF 2005 FIELD SEASON. FIELD NOTES, August 2006 -1 22 August 2006- Arctic Chief (west), Whitehorse Copper Belt, Yukon Territory, Canada reefer tv cnClGSed BketCii maps, ak'iCVe, for iv%atiGnS of the Saii~pleS described in tfie f0iiowing notes of this date. TM-06-8-22-1: Atop the veneer of carbonate rock rubble/"rubble-crop" which overlies the "massive" exposure of a/the dike at this site (Cf. Map#C). Portions of this exposure of dike rocks were sampled. Samples of the carbonate rocks were also taken. All samples were of "loose" material. However, the dike rock samples, in particular, are "sub-crop" of adjacent in-place portions of the dike. Samples feature "banded" and "dioritic" (?) rocks, among other types. [Refer to work of previous years at this locale for additional comments, details, etc.] GMC D~,T~ REPORT 3 4 4 ~ - F Page 55/117 TM-06-8-22-2: Locality shown on above map ("Page 3 of 3") is in the AC pit, up on the side of the wall of the northern corner of the pit entrance, where it adjoins/meets .the wall of the main portion of the pit. The geologic relationships displayed at this locality are shown,. variously, in the numerous photographs taken of this site in previous years (see "photo index" files). A rough sketch, ("Attachment T M - 0 6 - 8 - 2 2 - 2 - " ), cf. below, made in .the field shows the general spatial relationships of the materials comprising the "tongue" of darker materials into the host carbonate rocks. This sketch/"geo-cartoon" is .not to scale, since direct measurements were. not readily feasible due to difficulty of access. Approximate dimensions were estimated in the field, as well as by comparisons, from photographs, to the dimension of the exposure of sill-rock above this location which was pace-measured previously. This is a very interesting, perhaps "key", locality. It is the location of acopper-bearing "tongue" of dark materials ("skarn", +/-, presumably[?]) projecting into carbonate rocks at/nearfalong the apparent crest of a structural fold in the host carbonate rock sequence. This is the "gaudy" feature shown in many photographs, taken from various sites, .'during field work of previous years (2004-2005). Samples were taken of all principal lithologies/zones/etc. Represented were "hosdcountry" carbonate rocks (the predominant carbonate rocks in the sequence exposed here are light grey, with subordinate proportions of discrete interbedded sedimentary (presumably [?1) horizons of darker grey carbonate rocks [cf. photographs)). Also sampled were a variety of darker rocks, representative of "skarn-like and "igneous(?)" materials. Samples included in-place materials, as well as some "sub-crop" and "rubble-crop/float"; the latter samples were obtained immediately below those portions of this location not readily accessible. (Essentially vertical, or overhanging, wa(Is in places.) SUPPLEMENTAL NOTES REGARDING SAMPLE LOCATION "TM-06-8-22-2-A-, B-, C": (Cf. "Attachment TM-06-8-22-2-") TM-06-8-22-2-A-: Specimen "-1 n: from the central/medial portion of the medial zone ("X") of the greyish- greenish rocks. Specimen "-2": from zone "X", intermediate between specimen "-1 " and specimen "-3". Specimen "-3": from zone "X", adjacent to the upper part of zone "Y". Specimen "-4": from zone "Y", near/adjacent to the lower part of zone. "X". Specimen `°-5": from zone "YA <---> zone "Z" harder area. Specimen "-6": from zone "Y" <---> zone "Z" border area; more distal from zone "X" than specimen "-5". TM-06-8-22-2-B-: Specimen "-1 ": from zone "X". Specimen "-2": from zone "X" <---> zone "Y" "contact". Specimen "-3": from zone "Y" <---> zone "Z" "contact". Specimen "-4": from zone "Z". Specimen "-5": from zone "Z", somewhat more distal from zone "Y" than. specimen "-4°. Note Cu-staining/mineralization in/on this specimen, taken at the edge of the prominent 9-F CtMC DATA REPORT 3 4 4 Page 66/1~~ ~[ f ` \ `~ik~ ~ ~ ~ ~ ~;, ~ ~ ~ v ~= m ~ z~y . ~a ~ ~~ ~ ~, ~~ ~ ~ d ~ ~ ~ ~/ , W ~ a ~ ~~ :~ ~ ~ ~ ~ ~ ~! ~ ~ ~~fc z d ,~ ~ ~~ ~ ~ ~~ ~ ~ a ~ ~ ~ ~ ~ w~ ~ c ~ - ~ ~ ~ ~ ~ ~ '~ ~~ ~ t ~ ~ ~ ~~ ~ t ~ ~ ,~ ~ ~~- ~ ~ ~ ~ ~ ~ °-~ '~ i '~ ~ ~ :~ ., ~ ~~ l ,~~ ~ ~ ~~ ~ _ '` r~ j~ ~ ~ ~ °' ` t w ~ ~! ~ 9 1 Y ~IVit; DATA REPORT 3 4 4 Page s~/11~ green area shown on photograph #5 (and other photographs which show this `tongue- . liken geological feature). Specimen °-6": from zone. "Z", more distal from zone "Y" than specimens `-4" and °- 5". TPJl-06-8-22-2-C-: Specimen "1 ": from zone "X" <---> zone "Y°. Specimen "2": from zone "Z". The two specimens from TM-06-8-22-2-C represent .materials from the (easternmost) "tip" of the "tongue-like" feature, at the "end" of this structure where it terminates (in this exposure) against country/host/wall rocks. The six specimens from TM-06-8-22-2-B represent a "cross-section" ofi this fieature, further to the west from the "-2-C-" location. This section was taken from the medial "core" to the lower edge of this "tongue", into the wall rocks. The six specimens from TM-06-8-22-2-A represent another "cross-section", further to the west from the "2-8-" location, toward the western end of the exposure of this tongue-like feature. This cross-section atso was taken from the medial "core" to the lower edge of this "tongue", into the wall rocks. The attached sketch (( ``Attachment T M - O 6 - 8 - 2 2 - 2 - ") roughly depicts the relationships of the samples .taken to the "tongue"-tike" body overaiL Some comments on the character of the `zones" as adapted far purposes of field sampling are as follows: Zone "X": Made up of grey-greenish rocks of apparent (?) igneous aspect. Grain size of the specimens shows a general decrease from the centraifinedia( portion of the zone outward towards zone "Y" (specimens "-2-A-1" ---> "-2-A-2" ---> "-2-A-3"). Specimen "- 2-A-3" is adjacent to zone "Y", and features porphyritic texture, with an aphanitic groundmass, perhaps suggestive of a "chili zone" of sorts. Specimen TM-06-8-22-2-C-1 is somewhat more complex in character, having farmed out at the "tip" of the "tongue". Zone "Y": Comprised. of reddish-brown/black rocks of apparent "skarn" aspect, featuring apparent garnet, pyroxene, magnetite, +/- copper minerals,. +/-?. Zone "Z": Consists of wall/hostlcountry rocks of carbonate composition, variously affected by metamarphlsmf~i~etasamatism +/- °veinii~^y" {,'nagnetite?/+/-??). Zones `Y' "and "Z' ", which were not sampled due to appreciably greater difficulty of access, appear to be essentially similar ("mirror-images", so to speak), in general, to zones "Y" and "Z", respectively, "peripheral" to zone "X". Further musings on the TM-06-8-22-2- location. are as fiollows: This geologic feature apparently represents a "tongue" of skarn and skarn-related materials, projecting into adjacent carbonate rocks. This location is apparently marginal to the previously present principal mineralization!"ore-body" of magnetite-bornite- chalcopyrite, +/- ,now "mined-out" from the AC {west) pit. 10-F 6NEC DATA REPORT 3 4 4 Page 68/117 Perhaps it is not atypical, thus, of the conditionsfsituation extant rioting/responsible far the. more extensive minetaiization of the main ore zones. Hopefully providing an example, though at a smaller scare/"in miniature", perhaps, of the processes and results/products at this deposit. Possibly a vestige of more substantial skarn formation related to a portion of the ore body. This featurellocation is on the marginJperipheral to the mined-out pit. And there rs magnetite, popper staining, +/-? at this site. Copper staining reflect bornite, and/or chalcopyrtte, andlor......... ?? Apparent(?) presence of .certain silicate .minerals (viz. forsterite?, serpentine?, phlogopite??) indicative of a magnesian skarn situation? The carbonate countryfwall rocks are "on trend" with the peric[ase (brucite} marbles just to the north of this site. The nature of the zone "K" apparently igneous (?) rocks {ie. "dioritic", "porphyritic andesitic [?)") is of interest, as are the grain size/textural retationshipsl"intrusive" characteristics noted. Are these "igneous" rocks representative(?)/indicative of the characterJcamposition of the "main magma" responsible for the the metamorphism/metasomatism at the AC (west), +/- elsewhere in the area? And/or "modified" by assimilation/eontaminationfreaction etc.. etc. {?). Cf. other samples taken on August 8, 20fl6 elsewhere in the AC (west) pit, especially those of "dtoritic" {??) aspect collected in .the vicinity at the sumpJpond/"glory- hole" near the southwest corner of the pit floor (?). VYhat is the relationship of these rocks with those of the "dikes" in the. neighborhood? The porphyritic specimen collected from the. "tongue" has a fair degree of similarity in (megascopic) aspect to some of those dike rocks. Though presumably/supposedly these dikes were "later" than the metamorphism, metasomatism, ore deposition. The apparent lack of significant. "contact" metamorphic effects between dike rocks (for example at the "bird-like" dike exposure [cf. TM-Ci6-$-22-2-5-), or its [likely) extension at the nearby "massive site' exposure) and immediately adjacent carbonate wall rocks is suggestive/informative. As are the observed relationships in this "tongue". TM-o6-8-22-3: See above map {"Rage 3 of 3n) for location. Samples of "rubble-crop/float" materials collected along a traverse from the south wall of the pit entrance, where it meets the main watt of the pit, to the south. corner of the pit. The traverse proceeding along the footllower flanks of the southeast watt of the pit, just below the near-vertical/verticallovefianging wait. "Character" samples were taken,. from the pit entrance (carbonates}, thence southwestward. Collecting, sequentially, dark "orels", +/-, followed by "skarn"-materials {pyroxene/garnet, +f-) to the southern corner of the pit. Some white materials {carbonate?/??} were .collected beneath exposures observed higher above in the pit watt. Photographs of the AC {west) pit show general relationships/features. Faultsffault zones, So~iic with aSso%iated alteration {vis. green/gieen;Sh-yellow, rusty/reddish-Brown, esp.), were noted with moderate frequency in the pit wall abng the course of this traverse. Cane such zone occurs at the south corner of the pit where the southeast and southwest waits of the pit meet TM-t36-8-22-4: See above map ("Rage 3 of 3fl) for location. Numerous photographs {aver the years} feature some views of this location. Traverse was along the foot/lowermost flanks ofi the southwest pit watt, at/near the base of the vertical/near-vertical/overhanging wail Samples of rubble-crop/float character. Rocks predominantly "skarn"-materials {minor exceptions being several "white patches" in this southwest watt, remirtiseent of similar i 1 -1= GN1C DATA REPORT 3 4 4 Page 69/117 features observed in the southeast wall of the pit). This "skarn" comprised principally of pyroxene and/or garnet, with associated "pockets" of eu/subhedral calcite, garnet, minor chalcopyrite, +/-....). No "granitic/granitoid° rocks were noted along this wall of the pit. However, distal from the wall proper, toward the center of the pit, there is a relatively small depression at the. deepest part of the floor. A "sump"f"glory-holes, of sorts, presumably. As noted over the three years of this study, subject. to flooding, and formation. of a small "pond". Though this "pond° was appreciably "smaller/drier" on the present date. At this location, a pile {"float?/rubble?/subcrop°?} of dark ("dioritic"?) rocks was. noted (and sampled). Perhaps representative of racks occurring infnear/below this facation? Indicative of similar/"dioritic (?) rocks in place below? Perhaps representing "exoskarn" (??), or/and "endoskarn° (??). A portion of a phase/carapace/shell/border zone of the "main magmatic masse related to/responsible for the AC metamorphism, metasomatism, skarn and ore formation?? TIW-06-8-22-5: See above map ("Page 3 of 3") for location. Numerous photographs feature some views of this location. LocalBty is toward the top of the north wall of the AC (west) pit entrance. At the contact between the "bird-shaped" exposure of the dike and the adjacent/transected carbonate rocks. Samples were obtained from the area of, and near, the "chin/throat" part of the "bird". Cf. TCM photographs from previous years (2004, 2005) and this. date. In-place/outcrop samples of carbonate rocks and adjacent dike rock. Also some samples as "float" .from this area. Also other samples of .rocks as "float/rubble° in the immediate area. No specimens containing both carbonate rock and adjoining dike rock together in one sample were obtained, as all attempts to obtain such a sample succumbed to the blows of a hammer, and the two lithologies "parted company". The bond between these carbonate host rocks and the intruded dike materials is not physically strong; apparently a "sharp° contact indeed, here. Only relatively minor alteration {vis. some slight/moderate shearing/gouge, "serpentinization"//+/- (?), of the igneous rocks was noted. The white-buff-very light grey carbonate rocks ,give off a "ringing/tinkling/bell-banging" sound under the hammer or when pieces are struck against one another. Specks of light-brownish brucite-after-periclase apparent in these marbles. The igneous rocks are dark greenish-grey, aphanitic/very fine- grained at the immediate dike/host rock contact, with larger grain size (in places porphyritic, with apparent plagioclase, +/-?, phenocrysts) developing with distance from the .contact. It appears (from the. nature of this contact, and/or the lack of skarn or ore. formation [?]) unlikely (?) that appreciable (additional)- contact metamorphic {+/- metasomatic} effects occurred in the host carbonates, due to thermal or other effects related to these adjacent igneous "dike" rocks. The carbonate. rocks presumably having been previously subjected to the periclase marble level of metamorphism, in more pervasive/area) fashion, preceding the formation of this dike here [?]. While these "dike" rocks themselves .lack obvious features attributable to such a level of metamorphism, hence. appear to have been emplaced `post" periclase marble formation. END OF 2006 FIELD SEASON 12-F GMC DATA REPORT 3 4 4 Page ~o/ll~ COMMENTS ON PRELIMINARY ANALYSIS/"TRIAGING" OF ARCTIC CHIEF SAMPLES (TCM): All field samples were subsequently examined further, in preliminary fashion ("triaged"), by TCM in Haines, utilizing hammer, chisel, hand lens, acid bottle, and a 30x/60x stereo. microscope on~ rack surfaces (freshly-broken and otherwise). In some select cases, also examining grains-in-oil materials using apersonally-owned petrographic microscope.. Deferring to S. M. Aleksandrov ("SMA") for decisions as to thin-/polished-section petrographic analysis, etc., as he might see fit. In any case, the "low-budget" circumstances precluding appreciable petrographic thin-/polished-section preparation and analysis by TCM. A substantial amount of detailed analytical/laboratory. notes accumulated as the result of this preliminary examination!"triage" stage. Including observations, commentary, sketches, and photographs. The stereo microscope can be a valuable tool indeed. Due to the accumulation represented, they are not included en toto -nor even in .any great detail- in the present report. TCM can be contacted regarding specific interests, questions, etc. Selected materials (about one hundred specimens, in all) were then mailed to Dr. Aleksandrov, at the V. L Vernadsky Institute of Geochemistry and Analytical Chemistry,. Russian Academy of Sciences, Moscow, for examination, evaluation, and further analysis as he deemed appropriate to his own ongoing research. This latter work included hand specimen, petrographic microscope, microprobe analysis, etc. of representative materials of particular interest. The following are some selected comments, as culled from the analytical notes (TCM) mentioned. above. Of particular interest were observations dealing with samples which -- the entire specimen, or portions thereof -- were subsequently sent to SMA. Especially the. periclase (bruc'rte) marbles,. calciphyres, banded rocks and "ores°, etc. Descriptions, and sketch maps, of field/sampling localities are presented elsewhere (above) in the "Data Supplement" section of the present report. The sample labeling scheme used is exemplified as follows: TM =the sampler's initials; "04" =the year, 2004; "6" =the sixth month, June; "9" =the ninth day of that month; "3" =the sample locality/site for that day, per my field notes; the final number ("N") is .that assigned to a/this particular specimen. le., in this instance [TM-04-6-9-3-N]. 1981 Samples- TM-$1-7-30-1: "Skarn°. Garnet, pyroxene major minerals. Subordinate to minor amounts of "calcite/ carbonate"(?), magnetite, quartz, epidote, actinolite (w/chlorite?), idocrase, chalcopyrite, serpentine(?). And/or perhaps some bornite (?), tremolite(?), woltastonite(?). Garnet: Eu/subhedral, to anhedral, massive; reddish-brown; often enclosedlsurrounded by pyroxene, calcite. Pyroxene: Euhedral-subhedral, to anhedral, massive; dark green-blackish. Calcite: Euhedral-subhedral, to anhedral, granular, patchy massive;. pink-salmon-orange- white-clear colorless. Quartz: Anhedral to (some) subhedral; colorless, clear, glassy. Magnetite: Octahedral and cubic euhedral crystals; black. Some app~rpnt magnetite might actually be bornite(?). 1-A 6MC DATA REPORT 3 4 ~ Page 71/117 Epidote: Euhedraf, and also less-well-developed; lemon-lime to pistachio cobra "Actinolite/chlorite/tremotite"; "serpentine", in part{?): Sheaf-like crystals, eu- subhedral, and anhedral granular/massive; pate/light green to green. Serpentine: Fibrous; light greenish-whitish-colorless.. chalcopyrite: Eu-subhedral, and as less-we8-developed crystals. Assemblages/relationships: Magnetite occurs within quartz, epidote, calcite, and adjacent to chalcopyrite. Epidote occurs oNafter black pyroxene, some of which is eu-subhedral. Garnet occurs within calcite, as well as intergrown with pyroxene. Serpentine occurs with "tremolite/actinolite~. Quartz encloses magnetite, epidote; is noted "adjacent to" chalcopyrite. Quartz-epidote-garnet-calcite-pyroxene-magnetite. White granular wollastonite (??) adjacent to/on calcite; in veins/fracture fillings, adjacent to garnet. Some (at least) of the apparent "wollastonite" might actually be {"weathered" ?} calcite {??, +/-?}. "Vug-like" patches (maximum dimension observed aboutl0 cm.) of "calcite%arbonate' (euhedral and less-well developed), garnet (euhedral and less-well developed), pyroxene (euhedral and less-well developed), quartz {anhedral), chalcopyrite. Grains range .from +/- 2mm to substantially larger, and are well-developed crystals, for the most part. These "patches/vugs" are disseminated/scattered throughout the specimen, the remainder of which consists principally of pyroxene and garnet, coarser-grainedfmore massively-developed. This latter type. of intergrown garnet and pyroxene, +!- minor amounts of "alteration products" and scattered "dark/black opaques" comprise the bulk of this "skarn materialfrock". These "vugs/patches" are suggestive, in terms of general petrologic aspect, as well as geochemical, mineralogic, and textural characteristics, of some form of "late-stage/last gasp" crystallization related to relatively "volatiles-rich" fluid(s). There is a "pegmatoid" aspect to them. Their mode of occurrence, as often vaguely-defined features within a varied-size mosaic principally composed of "massive" garnet and pyroxene, is striking. Typically, somewhat "vaguely-defined", yet generally readily discernible boundaries/borders between "patcheslvugs" and surroundings are observed. The carbonate seems akey -the "typical" -feature, the essentially omnipresent mineral of these "patches". Together with the quartz, and sulphides, +/- "epidote, serpentine, etc., suggesting concentration of C02, Si, some form(s) of S, and, likely, H2O, +/-, presumably in a "fluid" phase(es?), within a surrounding environment of Ca-Fe-Mg-rich materials. TfVl-81-7-30-2: "Skarri". Garnet, pyroxene major minerals. Subordinate amount of `caicitelcarbonate"; minor/trace amounts of magnetite, quartz, epidote, actinolite, serpentine(?) chalcopyrite, malachite, borntte. "Possible" (?) pyrite/pyrrhotite/arsenoprite; and/or (??) some. tremolite, wollastonite, talc. Traces of several fractures .noted, with calcite andlor quartz on #raeture surfaces. Garnet: Eu/subhedral, to anhedral, massive; reddish-brown; often enclosed/surrounded by pyroxene, calcite. Pyroxene: Euhedral-subhedral, to anhedral, massive; black to dark green-blackish. I ntergrown with, often enclosed by, garnet Calcite: Euhedral-subhedral, to anhedral, granular, patchy massive; pink-salmon-orange- white-clear colorless. 2-A CMG ~A1~~ REPORT 3 4 4 Page ~2/1~~ Quartz: Anhedral to (some} subhedrat; colorless, clear, gtassy. Magnetite: Octahedral and cubic euhedral crystals, and as less-well-developed grains; black. Some apparent magnetite might actually be bornite(?); or other minerals}. As well, some of the magnetite might represent -perhaps pseudomorphicatly -replacements of pre-existing minerals (viz. esp. "borates"?). Epidote: Euhedrai, and also less-well-developed; lemon-lime to .pistachio color. "Actinolitelchlorite/tremolite"; "serpentine", in part(?): Shea#-like crystals, eu- subhedral, and anhedral granular/massive; pate/light green to green. Serpentine: Fibrous; light greenish-whitish-colorless. Chalcopyrite: Eia-subhedral, and as less-well-developed crystals. Bornite: subhedral and less-well-developed grains; black-purplish/bluish. Assemblages/relationships: Garnet after pyroxene. Massive pyroxene with the appearance of "being engulfed/altered byfto" garnet. Calcite after pyroxene, garnet. Minorftraces of epidote, +/-, on pyroxene. This specimen also. features "vug-like patches' similar to those described above (cf. TM-81- 7-30-1 ). 2004 Samples- TM-04-6-9-3-1: Calciphyre. Calcite, with marble texture. Disseminated brownish spinet(?), as well as apparent brucite pseudomorphous after periclase. (Cf. remarks on similar appearing periclase [brucite[ marble under TM-04-6-9-3-8, below). Other minerals noted are forsterite; phlogopite//+/- serpentine?, talc? (after/adjacent to forsterite), talc(?); magnetite (?), or perhaps other black mineral(s). Magnetite might (?) be pseudomorphous after Mg-Fe borates(?), +/-. TM-04-6-9-3-2: A "granitic"-aspect rock. Featuring fractures filled with epidote, calcite, quartz(?), magnetite(?). Rock also features black eu-subhedral pyroxene(?)/amphibole(???) [shows some apparent "approx. 80-degrees" cleavage]; plagioclase (note (subhedral] crystal. morphology, cleavages); quartz(?); some magnetite(?) +/- associated pyrite(?)/chalcopyrite(??), alt altering to "limonite". Also some epidote, on fractures, and in "vugs(?)" (after calcite?, etc.?), as well as marginal to - as alteratio,~ of(?) - plagioclase. A "quartz dioritic" -- perhaps a "quartz gabbro"(?) -- rack (now). "Altered" rock(?)/~endoskarnn(?). Or representative of a "plagioclase-pyroxene zone", .per SMA. TM-04-6-9-3-3: Zoned magnesian-skarn .material. An excellent example of its type.- Five distinct zones/portions occur in this specimen (the specimen is .approximately 11 cm in maximum dimension). A zone (on .the order of 3 cm, as exposed} of periclase (brucite) marble occurs at one edge of the specimen. (Cf. remarks on similar-appearing periclase [brucite) marble under TM- 04-6-9-3-9, below). 3-A 6MC DATA REPORT 3 4 4 Page ~~/il~ Next to this is a zone approximately 3-5 mm in width, .comprised principally of reddish- brownish garnet (?), with associated quartz?, chlorite??. ..Next to this is a zone (on the order of 2 cm wide) consisting principally of dark greenish/black pyroxene. Followed in turn by a zone, about 4 cm wide, made up .principally of phlogopite, +/-. Next to this is a zone of calciphyre, occupying the remaining approximately 2 cm of the specimen, along this "traverse" across its surface parallel to .the maximum dimension of the specimen. Perhaps representing a "vein-like" development of skarn? With similarities to sample "- 1 ", above. Portions of the specimen consisting of marble are principally calcite, ..with disseminated brownish materials?), some/most of which appears to be brucite after periclase, while some perhaps is more likely spine){?). The "calciphyre" lithology features major calcite, subordinate forsterite{?)/related alteration products {viz. "serpentine?/ phlogopite?, +/-?), as weft as -- perhaps -- trace amounts of magnetite (?) and/or spine) (Compare this specimen with specimens TM-04-6-9-3-10; -i i ; -12). TM-04-6-9-3-4: Pericfase (brucite) marble; calcitic, white-light grey. Containing sets of darker- colouredlgreyish cross-fractures. The fractures "filled/healed" with clear -- hence. the "darker, greyish" effect -- carbonatefcalcite{?). le. self-healedfrecrystallized". "Crush zones(??)". Rock otherwise rather homogeneous, mineralogicaliy and texturally. Though small disseminated brownish specks occur, some such being brucite after periclase(?), as well as (some) spinet(?) and/or......... ?? (Cf. remarks on similar appearing periclase [brucite] marble under TM-04-6-9-3-9, below). Specimen is a hard,"bell-banging" rock, which ringsfclangsftinktes nicely under hammer blows; or, especially, when thin slivers of the rock are struck together. "Chattering rocks": which chatter on -- amiably..... or irritably......, according to one's mood of the moment -- ; as one makes his way -- or, more frequently, stumbles along, slipping and sliding, -- over accumulations of rubble/float fragments of this lithology. The sort of rocks perhaps one. might be able to map °by ear", or even in the dark (?). Sharp edges, pointy corners, too........ TM-04-6-9-3-5: Carbonate rocks. Pericfase (brucite) marbles. Two "varieties" (sedimentary layering, apparently[?]) manifest in this specimen; one essentially white, the other "greyer"("carbonaceous/graphitic"?), with rather abrupt/sharp contacts between these "varieties". Set(5} v~ intersecting fr avttir es tianSei i both of these varieties of rocks., ~:ttting afro sS both similarly without interruption. These fractures are similar to those mentioned in sample TM-04-6-9-4 (above}, perhaps/likely as "self-healed"!recrystallized crush/shear zones.. Minerals present feature a "glassy" clear "quartzy"-looking crystalline material, intergrown with a duller, white, crystalline material which shows subhedral crystals (as "stubbyish forms/laths")when in lesser proportion to surrounding "quartzy" material. The latter also exhibits some eu-subhedraf aspects here and there, possibly of "quartz. aspect" (?). The "lighter" portion of the specimen consists of predominant "white" carbonate (calcite) material; the "greyer" portion of the specimen, as well as the transecting fractures/zones, contain carbonate/calcte, as well appreciable "quartzy-looking" mineral A "siliceous"I"quartzose"(?) periclase (brucite) marble. (Cf. remarks on periclase [brucite] marble under TM-04-6-9-3-9, below). 4-A 6MC DATA REPORT 3 q 4 Page 74/117 Tracefminor amounts of fine-/very-fins-grained black crystalline materials?) occur here .and there, including within fracture zones. These perhaps consist of graphite(?)/magnetite(?}/+f- ??. Also disseminated in this specimen are many somewhat obscure "brownish specks", which perhapsftikeiy (somewhat "unclear" in this particular specimen) are brucite, after periclase. TM-04-ti-9-3-6: Carbonate rock(s). Periclase (brucite) marble.. Two variants in this specimen. One a dark grey, the other a lighter grey-white, apparently interbedded {?}. Some fractures, especially apparentfonly present(?} in the darker variety. of rock here, with lighter material (carbonatefcaicite, +f-?) along the #racture surfaces. Might{??} the lighter "beds"/"layers" of carbonate rock actually be "wider°f"mega" shear zones, with recrystallized .carbonate, +/-?, along/within these zones {??}. One edge of one of the white "zones"/"layers" exhibits a distinct "ringing°/"bell-banging° character when struck sharply. The darker grey material features greyish vitreous-looking minerals}; carbonate/quartz{?)I+/-?}, and {appreciable) associated darkfblack disseminated materials?). The latter possibly graphite?!magnetite?/?"borates"?for ??. Note, in this darker material, brownish subequant (on weathered surface} grains of apparent brucite after periclase. And/or spinet(??}. In the lighter material, there appear to be at least two "predominant° minerals_ one "dull whitish", the other a tight grey, and perhaps "more vitreousp-looking.. Likely. periclase! brucite, and calcite. (Cf. specimens TM-04-6-9-3, 4, 5). (Cf. remarks on similar appearing periclase [brucite) marble under TM-04-6-9-3-9, below). to the darker material in this specimen, these two "predominant' minerals also occur, but .with a more substantial amount of black materials(s?}; viz.graphite? /magnetite?/ "borates"?f+/-??. These "whitish° versus "light-greyish" minerals are present in approximately coequal proportions in both the lighter and darker portions; ie., the "lighter" and the "darker" carbonate(?) rocksflayers comprising this specimen. Hence likely {?} represent periciasefbrucite and calcite. ((Might at least some of the "grey" material be fluorite(???}; note an optical. impression of sort of a "greasy" appearance, here and there. Though perhaps more likely this is also periclasefbrucite.)) TM-04-6-9-3-7: White carbonate rock. Periclase (brucite) marble. ~i~ir~jiii at least two Sets of intefS2Cting fra~aureS. The eartiei Set featur'~S greyish ("gCiartZy- tooking°) material (cf. specimens TM-04-6-9-3, -4, -5, -6, per above). The later set features some similar material, though containing appreciably more black materiatfminerat(s) - (graphite?/magnetite?/Mg-Fe borates??/tourmaline???f+/-?). The white carbonate material appears to consist of approximately coequal amounts of a white, "dullish-appearing° mineral, and amore "vitreous-appearing", clearer ("quartzy- Looking") mineral (which tatter, however, is not as greyish as the "quartzy-looking" mineral in/associated with. the fractures. (Cf. remarks on similar appearing periclase [brucite] marble under TM-04-6-9-3-9, below). In the "later" fracture-fillings/"veins", the black mineral(s) are the principal constituent, with apparent "spreading°/"diffusion° laterally into .the country rock 5-A GMC DATA REPORT 3 4 4 Page 75/117 surrounding these "veins". Much of the "vein-filling" is also adarkish-grey "quartzy- looking"/[rather, carbonate(?)] material (cf. the phases noted in samples TM-04-6-9-3, - 4, -5, -6, as above).. This specimen presents the aspect of "vein-filling" material, perhaps along "crushed" and "recrystallized" zones/fractures. Featuring a "self-healing" situation, in this particular case in concert with deposition of the black mineral(s)/material(s}. The dark veins offset the tighter. grey veins, slightly but noticeably. These darker veins are somewhat remindful of similar features observed at the magnesian skarn-related localities of Lost. Riverf6rooks Mountain/+/-Tin Creek, western Seward Peninsula, Alaska. Some buff/tanl"rusty° weathering (presumably) effects noted on older/"pre- hammering" surfaces of this specimen. Also noted on these surfaces are a number of apparently "residual" periclase --> brucite "holes"/depressions, displaying euhedral outlines typical of the genre. TM-04-6-9-3-8: White carbonate rock. periclase (brucite) marble. Displaying two setsforientations of intersecting fractures. The earlier set/orientation attitude contains a darker subset, with the aspect of a "crushed zone" (as per specimens TM-04-6-9-3-3, -4, -5-, -6, -7, above), and a relatively lighter subset. These tuvo subsets. are subparalle! to one another. This set is terminated abruptly by the second set/orientation attitude, which latter is manifest as an only-vaguely-discernible zonetfracture oriented at an angle of approximately 90 degrees to the trend of the earlier set. This later. fracture/termination vaguely shows some apparent recrystallization features along its trend. .This sample, otherwise, is a fairly "homogeneous" rock. {Cf. remarks on similar appearing periclase [brucite] marble under TM-04-6-9-3-9, below). TM-04-6-9-3-9: This specimen is a t~Y one. Consisting as it does of an excellent ("splendid", according to SMA's subsequent more complete analysis) example of a periclase {brucite) marble. Principal features (often clearly displayed, in superb fashion) include: "Original" periclase; as residual cores. of periclase, featuring well-developed euhedral crystal forms. Subsequent partial to apparently complete pseudomorphous replacement of periclase by brucite. Brucite occurs as radiating masses of eu-subhedral crystals (a "radial fibrousA texture /aspect). The long .dimensions of the fibres are oriented essentially perpendicularly to the original outline/faces of the periclase crystal replaced/being replaced. Various "facets/degrees/extents" of this are displayed throughout the entirety of this specimen. Apparently without any (recognized) preferred location{s) .for the "occurrence /degree/extent" of the process(es). These features texturally and mineralogical{y manifesting -- affording clear. evidence of -- the petrogeneticaily-key chemical reaction for the formation of periclase marble from precursorial dolomite: CaMg(CO3)2 ---> CaCO3+MgO+CO2. (Cf. H. G. F. Winkler, 1979, esp.). The specimen overall is a white/very light grey carbonate rock. (marble). It features a somewhat rectilinear system of fractures! "recrystallized/healed crush zonesn, with two 6-A G~i(; DATA REPORT 3 4 4 Page 76/117 predominant sets recognized, intersecting with one another at relatively high angles (ca. 6t? degrees +l-). One set consists of fractures on the order of 1-3 mm in apparent width, as viewed on the largest. specimen face; the other set consisting ofi fracture zones on the order of 4-5 mm in apparent width, as viewed on the same specimen face. This specimen face is essentially rectangular in outline, with dimensions of approximately 6.5 x 4.5 cm. The fracture fillings/"veins" are vaguely "zoned", with "darker/greyer" borders, and medial portions Tighter, more similar in color to the surrounding host rock marble. Associated with bath. the white translucent-clear material {calcite, texturally present as a crystalline mosaic) comprising the bulk of the carbonate rock/marble, and the greyish-clear phases} of carbonate(?}/+f-?? in the "veinsfveinfets/crush/healed zones", ..are dullish- white °blobs/patches'. Such a blob/patch displays (variously] ablack-brownish-greenish- yellowish central "core" of apparent ("residual/relict"} periclase, surrounded peripherally by white-brownish-grey-greenish, "waxy"!semi-vitreous, generally fibrous, brucite. to many cases the spatial relationships represent, essentially, brucite "caught-in-the-act" of replacing previously-formed periclase. {Mineratogically and texturally manifesting the petrogeneticalfy key reaction: CaMg(C03)2 ---> CaCO3 + Mg0 + CO2}. Numerous examples, variously-well-developedldisptayed, are apparent throughout this specimen. Many are, indeed, truly "exemplary". Typically, (Cf. the somewhat voluminous original detailed laboratory notes, and accompanying drawings, of the specimen examinations by TCt~I, not presented in this report.) Inmost places throughout thts specimen, the ratio (by visual estimation under the stereomicroscope) of carbonate {calcite}:periclase/brucite is on the. order of 60:40. The latter abounds, as areas of filled/partially-filled voids, "patches, "blebs", throughout the specimen, within the "white carbonate" as well as the "greyer, "veinlet" portions ofi the specimen. The fractures, the relationships among them, and between .them and the calcite and the periclase{brucite) occurrences, afford indications as to the geological history, timing, course of events, as related to the geachemicalfpetrogenetic episodes .represented in this specimen, and the Arctic Chief locality overall. {Cf. as well, in this context, similarities to other periclase (brucite) marble specimens from this, .and other nearby/stratigraphicafly equivalent locations sampled [as described above and below].] The fractures/crushed zones, with their associated recrystallized carbonate, +/-, material{s), appear to have formed prior to {?) the formation of the periclase. This seems likely, since the periclase crystals (and, significantly, their subsequently-replacing brucite) are apparently unaffected by these fractures/crushed zones, and also occur with essentially the same/equal concentrations/frequency within as weft as outside these zones. And the likely relatively fragile!/readily-deformedfobliterated radiating crystal habitslhabitats of brucite, as well as the .often well-developed euhedrai outiinesishapes of tine original periclase crystals, are similar/the same/identical ..within as well as outside these. zones of apparent structural disturbanceldeformation .and related/associated recrystallization. Likely they would have been distorted/damagedlobliterated had they existed prior to, or during, this fracturing.. ?M-04-6-9-3-10: Specimen features a .number of readily discernible metasomatic/metamorphic "zones. .These alt occur in the relatively small volume of this specimen. The dimension measured at aright angle to the attitudes of the "zones" as displayed on the "best° specimen surface is 8.5 cm. This zoning seems to perhaps exemplify the "primitive" type in a magnesian skarn {cf. Aleksandrov,1998 & etc., on zoning "in pipes and stockworks in tectonicaity crushed zones in the envelope of dolomitic rocks around granitic contacts"}. The zoning is manifest 7-A 6MC DATA REPQRT 3 4 4 Page ~~/1~~ mineralogicaliy, geochemically, texturally, as well as visually. Note some indications/evidence {viz. offsets, trends of mineral occurrences) of fracturing/faulting within this specimen, which suggest {per SMA; see "references"} perhaps a situation of "long-lived" tectonic/"crushed zone" setting? le. during .the. magmatic and post-magmatic stages. Although {per SMA, esp. p. 4 in the y 998 book} the nature and scale of .the zoning. in this particular specimen actually seem to suggest a situation of pre-skarn fracturing/crushed zone formation, which features became sealed during the formation of the primary metasomatic zoning {seemingly as exemplified in this specimen {?). The "zones" featured in this specimen are here-labeled (solely for purposes of description) and here-described, from "left to right" across the particular orientation and face of this specimen selected for description. The first zone ("A") consists of a white-light grey periciase (brucite} marble. The major mineral constituents of this marble are calcite and periciase {brucite), occurring. as a crystalline mosaic. The periciase (brucite) occurrences are often rather well-developed {some "classic"), nicety displaying the periciase "core"-brucite "rim" relationships, etc., as noted in other marble specimens collected/observed at this sample location, as well as at other sites at the Arctic Chief.. [Cf. remarks on similar-appearing periciase [brucite] marble under TM-04-6-9-3-9, above. See also observations, comments, sketches, in detailed laboratory notes {TCM), which are not included in this report.]. Trace amounts of subequant sub-euhedral crystals of a greenish-blacfc semi-transparent mineral{s) are noted which might (?) be spines, or pyroxene {?). One such observed is associated with a small grain of a black crystalline material which might be magnetite (?}, or PYroxene (?}, or (??}, The "best" such euhedral crystal of a black mineral noted shows vaguely-defined striae/cleavage {?) subparaliel to its long dimension, suggestive of a pyroxene. This crystal may well be twinned, as an apparently similar crystal lurks beneath, vaguely. defined within the surrounding crystalline mosaic of calcite, periciase {brucite], etc., comprising the buck of the marble. This crystalline mosaic also features disseminated "very-very"-fine-grained black "platy" (graphite?!magnetite?Iphlogopite?/??) speckslgrains, .some associated with apparent "rusty" (hence iron-bearing?} material(s). Zone "B" is a "forsterite, +/-?, caiciphyre". it consists principally of predominant calcite (as a crystalline mosaic), and, generally (except where present in some .concentrations, as "fayerslbands/ienseslpatches/streaks"), substantially subordinate forsterite/forsteritic olivine. The zone is "somewhat banded" overall, and features. darker grey, lighter grey, and yellowish-greenish -subzones°/portions, as weii as varying grain .sizes (some discerniibte megascopically). Compared to zone "A", zone "B" features a greater amount of black vitreous crystalslaggregates, some of which are associated with patches/margins. of yellow-brown material similar to that observed in zone "A" in association with black crystals of (?}. Also note some crystals (some apparently 6-sided) of clear vitreous aspect, with patchy distribution of internal disseminations/"dustings" of a "very-very"-fine-grained chocloate brown material. Ali set in the. crystalline mosaic "matrix" of the predominant. calcite. The concentrations of greenish, black, and brawn-dusted materials are most apparent as occurring in ill-defined but discernible "bands", which define the "banding" within this zone, occurring in subparatlel aspectforientation to .the major "boundaries" between "zones" 8-A 6MC DATA REPORT 3 4 4 Page 78/117 (ie. marble, then calciphyre, then forsterite, serpentine, pyroxene, garnet} in .this specimen. These "bands" are often more. like wispy patches, .tenses, actually, within this zone "B". "lnterbands" containing more, or less, marble/calcite crystalline mosaic. material occur as well, essentially by varying degrees of abseneellack -- default, as it were -- of other constituents. The zone "B" vs. zone "C" boundary, if indeed a "B-C boundary" actually exists as such, is "vague"; perhaps illusory{?j. Though the concentration of green mineral{s) increases from ~B"__~"C"__~"D" Zane "C" consists of a forsterite calciphyre, similar to "B" except for a greater proportion of "yellow-green" mineral constituent(s), principally forsterite. Zone "D" is lioht_~reen_in color. with a veflow tinge, due to its_increasingly forsterite-rich (yellow-green mineral) content, becoming an essentially "monomineralic" zone (though with scattered black sub-euhedrat opaque grains -- magnetite?) distally/ from "C". At the distal-firom-"C"/.proximal-to-zone "F" portion of this .zone {ie. "D"}, is a relatively thin subzone ("E") consisting of serpentine (+/- same forsterite}., developed essentially continuously along this "border/boundary". This is probably the "bottom" of zone "D"s _if _ as seems not unlikely. _tha_ presumed source of the metasomatzina fluids was toward zone "F". {???) A "monomineralic forsterite" zone, per SMA(?). subzone "E" is light green, "waxy" in appearance, comprised principally of crystalline serpentine, with preferred orientations of the tang dimensions of the prismatic-appearing crystals -- ehrysotile, or perhaps antigorite (?) -- in growth positions (apparently), essentially perpendicular to the boundary with zone "F". It is highly fractured, with some white fibrous crystals (talc?/+/-?) also present, fining the fractures/seams. At the distal- from-"F" margin of subzone "E", a thin interval of "darker/denser"-appearing material of undetermined .nature (representing depositional conditions more conducive to a "massive" form of crystallization of a serpentine mineral, perhaps antigorite?), occurs, separating "E" from zone "D". immediately. adjacent to/"below" this "basal" serpentine-rich subzone ("E") is a relatively thin layer of red-brown garnet, which has invaded through the black pyroxene zone ("F") adjacent to zone "D". This type of red-brawn garnet -- comprising the predominant mineral of zone "G" -- is seen in zone "F", engulfing black pyroxene euhedra/masses. Zone "F" is dark grey to blackish, with a reddish cast. tt is comprised principally of very fine grained, to massive, pyroxene, +/-, as a "skarn°. The pyroxene euhedra occur as black stubby prisms, with good cleavage displayed. Somewhat intePTriiicei~tt"y developed befween zones "E" and. "F" is subzone "P", comprised principally of phiogopite, +/- perhaps subordinate amounts of other material(s). Developed "below/subeven" with the serpentine horizon of subzone "E", "P" manifests itself as pods/lenses of phiogopite. These podsllenses occur immediately adjacent to serpentine on one side, and to pyroxene {+/- garnet) of zone "F" on the other side. In some places, observed clear micaceous materials may -- at least in part -- actually be talc (?), while- in other {most) places the micaceous mineral is darker/greenish, and. most likely phiogopite. An additional, .rather intriguing, situation seems to present itself in this particular portion of the specimen: Other minerals present in this general "horiZOR" include opaque phases (in minoNtraee amounts). These include euhedra/"octahedra"(?) of "brassy"-appearing opaque material(s); S-A GMC DATA REPORT 3 4 4 Page 79/11 perhaps chalcopyrite (?), or chalcopyrite after magnetite (?). Possibly (??} valleriite, tochilinite, etc. {???). Some opaque masses feature ayellow-brown/"bronzy" material of pyrrhotite "aspect, but in direct contact with black material which may be>include magnetite {?!?}. Some of this bronzy material apparently has a "prismatic" crystal habit, variously developed. The opaques seem to be transected by garnet, +/- quartz(?), +1-carbonate{?), at least .locally. Elsewhere in this same general "horizon°, some apparently prismatic (or, perhaps, actually an "end-on" view of "layers"??) crystals of "bronzy° opaque material(s) are present, in direct contact with (apparent) pyroxene (magnetite??). In this particular occurrence, the "prismatic° aspect of the bronzy opaque material might, alternatively, actually represent manifestation of cleavage on subjacent pyroxene crystals (perhaps undergoing alteration/replacment??). This "horizon" is essentially within the zone "F° vs. zone "G" transitionlborder, with boundaries irregular, vague. As noted above, zone "F" contains appreciablelprincipalty pyroxene, occurring as black stubby prismatic sub-euhedra[ crystals, showing good cleavage. Might {??), per an observation by Ramdohr, the "bronzy opaque" material occur as an "encrustation" on pyroxene?. Asa "preferred" {for valleriite/etc.) mode of occurrence "as encrustations....... associated with serpentine, etc......." {Ramdohr). Pursuing this thread further, is the black °pyroxene" in contact with the bronry opaque/valleriite(???) actually pyroxene? Or, perhaps, magnetite? [tn an association. of garnet+/-quartz{?)+/-calcite+/-magnetite+/-valleriite/tochilinite.+!-pyrrhotite ??] Zone "F" becomes decreasingly a discrete entity as admixture withlreptacement by garnet, opaque minerals, +/-, is shown/represented through zone "G" to the distal edge/tip of the specimen. Zone "G" features a dark brown-reddish cast overall, due to the predominant garnet. This zone is, essentially, representative of "garnetiferous skarn". pyroxene, magnetite, other opaque minerals, including sulphides, occur, variously, in subordinate/minorltrace amounts. Some `"rusty" patches occur. Copper "staining", apparently as malachite, +/-, occurs at the extreme tip of .the specimen. Thus, in summary, a verv interesting specimen. Essentially a "microcosm"of the sequence: Periclase {brucite) marble -- calciphyre{s) -- forsterite{+/-) -- pyroxene -- garnet+/-opaque minerals "zonation°. With calciphyres, forsterite, phlogopite, serpentine, opaques {perhaps including vaileriite/tochitinite??). Each in its "proper"/appropriate "position", spatially and genetically, petrologically and geoehemically. (See Aleksandrov, 1998, & etc.). This specimen displays: Periclase (brucite) marble Catciphyres, with forsterite, +!- nnetasomatic zoning of the magmatic stage Subsequent (partial, at least) effects of post-magmatic "alterations", .through at least the "acid stage" Minerals such as spinet, phlogopite, serpentine; magnetite, chalcopyrite, garnet, pyroxene TM-tZ4-6-9-3-11: This is a specimen with a number of aspects of magnesian skarn displayed in "microcosm": Blocks/fragments of apparent perictase {brucite) marble, with rims of garnet, adjacent to pyroxene skarn material; then phlogopite +l- serpentine, then forsterite, then once again back into pyroxene skarn, followed in turn by another garnet rim, around another block/fragment of marble.. 10-A G~~~ DATA REPORT 3 4 4 Page so/11~ Phlogopite is very-well-developed, serpentine we{I-developed. Spinet, +/- magnetite, +/-?, occurs scattered throughout the specimen. Note periclase and brucite, with character .and relationships as noted in other calcitic marbles/ calciphyres, from this, and other localities at the Arctic Chief. Enterpretation of the observed overall relationships in this specimen remains somewhat "uncertain". Do these blocks/ftagments represent "nodules" of marble/calciphyre, rimmed by "reaction zones" (??) of garnet, as remnants within pyroxene skarn? Or might they be related to "apophyses" of "granitic"/? melt, as "tongue-like" features intrusive into host rocks of carbonate (or previously-formed skarn material?) nature. With the pyroxene, garnet, phlogopite, serpentine, etc. observed being ancillary to this sort of situation. (Cf. TM-04-6-9-3-1, and -3, specimens with similarities to this one.) TM-04-S-9-3-12: Specimen. (maximum. dimension = 8.5 cm) contains a number of "zones", especially well- displayed across one of its faces. In order, along a distance of 5.0 cm across this face, in a direction ("left to right") perpendicular to the .trends of these zones, the relationships observed are as follows: From the leftmost edge of the specimen, a .zone of reddish-brownish garnet, with minor calcite, 1.5 cm wide. A zone of pyroxene skarn. Predominantly consisting of a relatively light green pyroxene, with minor/trace spinet, +/-?. This zone is on the order of 2.0 cm wide. A zone featuring predominant phlogopite, with lesser calcite, spinet(?), "rusty" magnetite(?), talc (??). This zone is on the order of 1.3 cm wide. A thin zone (approximately 2-3 mm wide) along the rightmost edge of the specimen. {t consists principally of serpentine, some clearly fibrous, and minor "rusty" opaque material, presumably magnetite, +/- ?. Additional observations: Black "very-very"-fine-grained, black ("flaky", at least in part) crystals/materials occur disseminated throughout the "pyroxene skarn" zone. The garnet zone has an aspect suggestive of an "apophysis"/tongue. (As discussed by Aleksandrov, 1998, 8~ etc. Especially note a diagram depicting the development of zoning around an "apophysis"....... Also, on a larger scale, the similarity to known relationships at the Holton/Hot-Kol, North Korea, locality/deposit.) [As a further observation, it should be noted that there actually appear to be a number of similarities between this Korean deposit and the Arctic Chief). The shape/orientation of the adjacent pyroxene skarn, as welt as that of its adjoiiUng neighbor, the phlogopite, +/-, zone, mimicking as they do the shape/outline of the garnet zone, add to this "suggestiveness". Similarly, though not as well-displayed due to its location on the edge of the specimen, the shape/orientation of the serpentine, +/-, zone further substantiates this "apophysis-like" impression. .The serpentine occurs intergrown with, and likely from, adjacent phlogopite of the phlogopite +/- zone. Phlogopite occurs as well-developed euhedral cxystats, tight olive green to dar[c olive green in color, often with physically interleaved/interlayered other minerals (viz. calcite?, +/-?). Given the nature, and "position", of these "zones", it might be speculated that a zone featuring forsterite, +/-, might weN have existed "beyondH/adjacent to the 1 1 -A ~ GMC DATA REPORT 3.4 4 Page s1/11~ serpentine)"phlogopite-serpentine"(?} zone observed in this specimen. TM-04-6-9-3-13: Specimen is on the order of 5.0 x 5.5 cm. tt features several "zones, especially weii- displayed on one of its relatively flat surfaces. in arder, along a distance 4f approximately 5.2 em across this face, in a direction ("felt to right") perpendicular to the trends of these zones, the relationships observed are as follows: A zone of "calciphyre", on the order of 3.7 cm wide, from the left edge of the specimen to the adjoining zone to its right. A zone on the order of 0.9 cm wide, consisting of pyroxene skarri, with minor associated spine)(?), +l-?. A zone consisting of serpentine, +/- forsterite, +/-?. It is discontinuously developed, .with a maximum observed width of about 1 - 2 mm. A zone approximately 5.0 mm in maximum observed width, extending to the. right edge of the specimen. This zone consists predominantly of phlogopite, +/- associated talc(?), +/-?. The .calciphyre zone presents some indications of additional "subzoning"/banding within it, but this is rather "subtle", at best {especially under the stereomicroscope, on a rock surface}. The ca{iciphyre is made up predominantly of a crystaflirie calcite mosaic (ie. a "periclase]brucite] marble"), with lesser amounts of associated "lights, and °dark" minerals. These include forsterite, pyroxene, vesuvianitelidocrase(?), spine), +l-?. Trace quantities of .opaque minerals, featuring magnetite, +/- valleriite?, +!- pyrrhotite?Ipyrite?farsenopyrite??-loetlingite??, also are present, as lenslike/streaky occurrences. The calciphyre also features some patches of garnet(??)F+/- magnetite{??) -- as "rusty" black crystalline sub-euhedral grains. In association with the surrounding calcite mosaic, same particular examples of this material(s) are also noted to be irr close proximity to traces/specks/crystals{?} of a bright blue-green mineral(s). The fatter range from sub-euhedral, are tabular-prismatic, and appeaNfook "coppery". le., chrysocolla, +/- malachite, +J- azurite (?). Or, sometimes seemingly "emerald- turquoise colored". These "coppery" materials appear to be "vitreous-waxy" in aspect, and are concentrated in a "patch/lens/layer" of the "rusty" black minerals. Additionally, disseminated sporadically throughout the serpentine zone and its environs, are some black-very dark brown vitreous crystals, not uncommonly as euhedra(subhedra with six-sided or eight-sided aspects. Some are "dendriticnl"snowflaky" in appearance, perhaps as crystal aggregates/skeletal crystalslgrowth forms. Remindful of manganese oxide "dendrites". Arb©reseer-il, overall. i~dith ~~~ai~y {variously) well-developed. "six-rayed„ branching forms displayed. Skeletal crystalslforms(?); possibly borates{?); graphite{?), +/- ? TM-04-6-5-3-14: .Specimen is 6.5 cm in width, as measured across the face described here. Consists of a number ofi "zones", characterized for descriptive purposes principally by overall color, mineralogy, texture. As observed, from "left to rightH across the face, these zones are as follows: 1. Qn the order of 6 mm and, variously, less in apparent width, at the leftmost edge of the specimen. Greenish, consisting principally of phlogopite, with minor calcite, talc{?). 2. Adjacent to zone 1. Approximately 1.1 crrt in apparent .width, variously, and 12-A Gf~G DATA REPORT 3 4.4 Page $2/11 conforming to the shape of the adjacent zones an either side. Greyish, consisting principally of calcite/"carbonate", with some associated periclase (brucite}, and. minor/trace amounts ofi relatively finer-grained "dark" minerals (spinet?/magnetite?/+/-?). A "periclase (brucite) marble"/"calciphyre(?)~. 3. Adjacent to zone 2. A "fens"/"tongue of material comprising zone 5 occurs within zone 3, occupying an apparent width of ~ .5 cm in the' central portion of zone 3. The .apparent width of zone 3 is 1.5 cm on the "left" side of this lens/tongue, and 1.t) cm on the other side of ft. Zone 3 is comprised. of "calciphyre", containing predominant calcite, with associated periclase (brucite}, and minor forsterite, +/-pyroxene. 5. The above-described zone 5 is made up of principally ofi patches ofi reddish-brownish garnet, as well as some calcite, minor forsterite, epidote?/serpentine(?), and some blue- grey .material which may be zoisite/clinozoisite/+/- {?). 4. Approximately d.8 crrt in width, adjacent to the "rightmost" .portion of zone 3, and an to the "right" edge of the specimen. Features appreciable pink and green (epidote?) and pink (zoisite?) materials, as well as "other" minerals, all "dark", same opaque. Relatively fine grain size precludes definitive characterization (on a rock surface, with the stereomicroscope) of the materials comprising this zone. The overall "aspect" is suggestive of "epidotization"/ "alteration" of previously-existing material(s). Might zones 2, 3, 4, 5 represent "marble%alciphyres" (2 and 3}, associated with (4 and 5) "veins"/"apophysis-related" features? After having been broken .into several smaller pieces, this specimen shows some interesting "zonai° -- "transitionatN -- "banded" aspects/features. Especially as regards the "talc-skarn"-like(?) garnet-epidote-opaque /"other° dark mineral(s)-"blue-grey" zoisitelclinozoisite(?} association/"assemblage°. TM-tD4-6-9-3-i 5: This specimen rather "complex". A "hodge-podge"/veritable "witches' brew". "calciphyre"(?)/"marble"{?);"originally". Featuring (relict) "prograde"(?), as well as "retrograde" (ie. "magmatic stage", and "post-magmatic stage"}, assemblages. Minerals recognized/perhaps present are pyroxene (diopside?), garnet, magnetite, calcite, phlogopite, spines(?), .forsterite(?), +/-?. Patches/lenses/"apophysesU/"fingers" of pyroxene/diopside(?}, +/- , occur. ,These rimmed with/outlined by reddish-brownish garnet, calcite, +/-?. The other minerals/assemblages occur between/among the several such "apophyses"(?) present. Apparently (?) representing a portion of what was originally a magnesian skarn, with subsequent "retrograde" ("post-magmatic; late early-alkaline <---> acid stages", +/- --->?}. Illustrative, thus, of the general trend/sequence of metamorphic and metasomatic C1Ie1 {t$ w1 Ilc1 i were involved in the history. of this st.JGC':Imen. A! 1Id, thus, by exien$ioi ~~, to the Arctic Chief deposit as a whole/overall (?). This specimen one of several collected at this sampling site as represenfi~ the "skarn° material(s) -- the "darker racks", ie. -- of the "apophysis(es)" into/ .associated with the lighter surrounding carbonate (viz. marble/calciphyre) country/host rocks at this locale. ["Representing", though not necessarily -- though of course "hopefully" -- "representative" of such, ie.] 13-A GMC DATA REPORT 3 4 4 Page 83/117 TM-04-6-9-3-16. Specimen is made up of a number of "zones", manifested by color, mineralogy, texture. illustrative of, "representing" (not necessarily "representative" of} the "skarn"-like darker materials} occurring as apparent "fingerflensfapophysis" features into/associated with the lighter-colored "carbonate" country rocks at this locale. in the direction perpendicular to the "zones", the distance is on the order of 3.0 cm, across the face of .the specimen. From "left to right" along this direction, the. zonesfmaterials encountered are as follows: 1. Approximately 1.5 cm in apparent width. Principal constituents recognized in a texturally "complex" rock mass include calcite ("marble", ie.}, scattered phiogopite, otivinefforsterite(?}, +/-?. Or perhaps better termed a "caiciphyre" (?}. A dark "horizon"f"subzone" of pyroxene, +/-?, occurs in one portion of this zone, toward the side adjacent to the adjoining zone "3°. At the edge of zone 1, immediately adjacent to zone 3, is a thin "layer"f"subzone" comprised of principally of olivine/forsterite(?}, +f_?. 2. Occurring within the central area of zone ("1 "} is a "lens/patch" of "exoticfforeign" material, which is designated as "zone 2". It is "tinged" with/comprised at least in part of reddish-brownish. garnet, and epidote(?}, as -- apparently(?} -- some. sort of "veinfreplacementn materials}. 3. About 1.t3 cm in apparent width, zone 3 is a light greyfwhitish "band", consisting predominantly of calcite ("marble", ie.), with trace amounts of scattered "dark° materials}. A thin, discontinuously-developed "subzone" rich in phlogopite, +f-, occurs along the margin of zone 3, adjacent to zone 1. 4. On the order of Q.5 ern in apparent width, zone ~ is made up predominantly of phlogopite, some calcite, +f-?, as a "dark bandlhorizon" in the specimen. 5. Occurring along .the "rightmost° edge of the specimen, zone 5 is essentially a thin "rind"/"skinn of either weathered specimen surface, or, perhaps, vein-related/alteration materiat(s}. The materiat(s} have abluish-greyish hue, with indications of vitreous aspect, perhaps also displaying some prismatic forms. TM-04-6-g-3-1 ?: Specimen is a porphyritic igneous intrusive rack, apparently, of "intermediate" ,composition. Representing a dike, pert7aps "latent"afterp (?} the metamorphicfinetasomatic activity responsible for the r`ormafion of the Arctic Chief deposit (??} [Cf. "Keferences' SeCtlon Of this report.].. Or, alternatively, perhaps at some, likely "later", stage during the formation of this deposit. in either case, this rock perhaps -- likely? -- crystallized from a .melt related to, or a part of, the "main magmafintrusion" responsible #or the metamorphismfinetasomatism at the Arctic Chief locality, with attendant formation of this ore deposit. [Cf. other remarks by the authors elsewhere in this report.]. This specimen features phenocrysts of zoned sub-euhedrat plagioclase (with some included "iron-affected" j Viz. "magnetitef+l-?".] core and .marginal areas. [Much "magnetite" began to crystallize fate in the crystallization of plagioclase, as vdell as during subsequent. matrix solidification.] Such plagioclase is the predominant phenocryst mineral present, with 14-A 6Nii~J~~ REPORT 3 4 4 Page s4/11~ subordinate amounts of quartz (eu-subhedral, and often somewhat. broken up). Also noted are a few scattered subrounded "lithic fragmentsH/"inclusions" {"cognates?), cantaining, variously, .plagioclase, pyroxene/amphibole(?), quartz, magnetite. Also present. are trace amounts of "micaceous material" {likely "biotite")?/pyroxene, amphibole? subhedra, of similar size to the phenocrysts, which perhaps represent portions of "relict/disaggregated° lithic fragments. The groundmass of this specimen is fine-grained, grey-green tin color, featuring plagioclase sub-euhedral crystals, set in a surrounding matrix of quartz(?), magnetite(?), +/- another silicate mineral which may be amphibole (??) and/or pyroxene(??). This matrix appears to be tov light. in color to contain appreciable amounts, if any, of such mafic silicates, however. Thus, rather, perhaps. a matter of "dusty° quartz/+/-, with finely disseminated opaque{s) mineral(s) -- Ariz. magnetite, +/-. Some potassium feldspar might also be present, as matrix material, and/or as "micro" phenocrysts (??). However, this is difficult to ascertain with confidence, using only a stereomicroscope on rock surtaces. This specimen is moderately fractured, and "veined". The fracture-fillings/veins feature a thin medial zone, generally darkfblack (magnetite?), with adjacent borders made up of white material(s), perhaps .quartz?/carbonate?/feldspar(s)?. TM-04-6-9-4-......... The collected specimens from this locale include carbonate rocks and "skarn" material(s). Three of .the latter "-17-A, B, C" feature "skarn" materials and "ores". These specimens are from outcrop/rubble-crop, at a high "bench" location, with -- at present -- not much directly above the sampling area except air, birds, aircraft, etc. to have contributed "significantly. out-of-ptacen material to these samples. (Bulldozers, etc. excepted, of course.) i'M-04-6-9-4-1: An example of perictase (brucite) marble. This is a somewhat weathered/altered(?} specimen. Rock contains predominant calcite, perictase (brucite}, and a distinctly minor/trace amount of disseminated dark-black materials}, probably at feast in part magnetite (note "rust), though some might be graphite(?). The "pock-markedn .weathered surfaces are of interest as regards recognition/ identification of rock constituents. Much useful information to be gleaned from scrutiny of "rustyn surfaces. Periclase (brucite) and calcite are present in essentially subequal amounts, intergrown throughout the specimen. Comparisons with observationsicomments regarding similar-appearing specimens elsewhere at the Arctic Chief suggest not at all dissimilar rocks. Qf particular interest in this regard are comparisons with samples from TM-04-6-9-3, & -5, locations, which are just across the Arctic Chief (west) pit entrance cut, to the "northish~ of this "-4~ locality. Carbonate, and other, rocks, apparently/essentially "on-trend" across the pit entrance cut here. TM-04-6-9-4-2: Specimen is an "interesting" one material portions. With apparent chalcopyrite/+/-? A combination of perictase (brucite) marble and "skarn" disseminated -- in .fair amount -- within the carbonate i 5-A GNiC DATA REPORT 3 4-4 Page s5/11~ rack adjacent to the skarn material. The marble apparently having been invaded by sulphides, featuring chalcopyrite, +l- galena{??), +l-?. The marble is comprised predominantly of calcite and periclase (brucite), with some disseminated pinkish-light brownish .euhedra which. may be spinet(?), and/or "flourite"{???jl+/-?. A "banded"!gradational contact/intercontact exists between marble and "skarn". In part at least. along "seams/fractures/shear zones"?. Some evidence of "internal shears/slip surfaces/slickensides/seamlets" withinfthroughout "skarn" as -well as marble. "skarn" consists of pinkish-brownish garnet, sulphide minerals (disseminated/semi- concentrated; chalcopyrite?!+/-?}, calcite, quartz(?), +/- trace of "epidote-like" coloration here and there, +f-?. One "pod/lens" of "skarn" seemingly occurs as an "offshootltongue" from the banded portion, into the adjacent marble. The weathered surfaces of this specimen afford supplementary informationlevidence regarding mineralogies, textures structures. TIUf-04-6-g-4-3: A specimen featuring "banded skarn" adjacent tof"invading" periclase (brucite) marble. Quite similar to specimen ThA-04-6-9-4-2 (cf. .above). Marble predominantly comprised of calcite and periclase (brucite}, with some disseminated sulphide (chalcopyrite, +/-?) mineral(s), +1-graphite?, +/-?. This marble. is quite similar to .that at other nearby localities elsewhere at the. Aretie Chief (viz. TM-04-6-9-3, - 5). "skarn" consists of pinkish-brownish garnet, pyroxene; sulphide mineral(s) -- chalcopyrite(?), +<-? -- calcite, black opaque material{s)/magnetite(?}, +P-?. TM-04-6-9-4-4: A large (hand-size} specimen, broken into three pieces .(which fit back together like pieces of a jigsaw puzzle). Displays "banding",overall, in varieties of greys, black,whitish, pinkish-brownish. Piece #1. The largest piece. Comprised of a number of "layerslbands". Layer "A": White-grey periclase (brucite) marble. Consisting of predominant calcite, and subequal (periclase (brucite). Compare with other similar marbles at nearby locations at the Arctic Chief (viz. TM-04-6-9-3, -5). There are trace amounts of black material(s) -- magnetite(?}, graphite (??), +/-? -- disseminated throughout, often in "pockets" of concentrations, and/or along "seams" within the rock. Also scattered eu-subhedral crystals (tetrahedrons?, +!-?) of pinkish-greyish-brownish materia! (spinet?) disseminated in this.. layer as well. Trace amounts of sulphides (chalcopyrite?) are noted, "smearedout" along a "seam" (a "mini"-crushed zone) "heated" with recrystallized(?) calcite. Layer "B": A band of "darker" materials, adjacent to "A". Comprised of black. mineral(s) -- pyroxene?, magnetite??, +f-?, pinkish-brownish vitreous crystalsFinasses --garnet, +i-?, caiciteimarbie??. Some "hematite/limonite' like materiai(sj islare associated with the black mineral(s), as well as along "mini-seams" across the rock, subparallel to the "banding". Layer "C": A thinner band adjoining "B". Composed of somewhat more coarsely-crystalline calcite, perhaps due to recrystaitization along a "seam"(?) Trace amounts of pinkish- brownish euhedra! (tetrahedral?) crystals (spine)?/or??) occur .sporadically within this band. There is also occasional sulphide(?) material{s), as well as, .more commonly, some reddish very-fine-grained crystalline. material which might be hematite(?)1+/-?. Layer "D": Adjacent to "C", this is .another "dark" band, similar in aspect and thickness to layer ~B". It Ges subparallel to the other bands in the specimen. Layer "E": Adjacent to "D". This a lighter band, made up principally of a periclase (brucite) marble/"calciphyre"(?), similar texturally and minera(ogically to "A", but with 16-A GMC DATA REPORT 3 4 4 Page s6/~~~ a somewhat greater proportion of "darker" constituents. These latter present as dark grey or black sub-euhedra (pyroxene?, magnetite?, traces of sulphides {chatcopyrite{?), perhaps galena?? and/or molybdenite(???), +!-?}, disseminated throughout the surrounding calcite and periciase (brucite) .principal constituents. Piece #2: Adjacent to%antinuing from Layer "E". Layer "F": Essentially similar to the description of "E", above... Layer "GA: Next to "F". is a whiter band, similar to the material described as layer "C". above. Like it, "G" as a somewhat more-coarsely-drystalline interval than the "marble/ calciphyre" bands observed elsewhere in the specimen.. Relatively "pure", preponderantly crystalline calcite, though with some concentrations of sulphides, +/-?, especially along the margins of this band/layer. Layer "H": Adjacent to "G", this is another band of "intermediately-darker" (?!?) aspect, somewhat similar texturally and mineralogicaiiy to some of the other bands in this specimen, such as Layer "E" in particular. Layer "I°: Adjacent to "H", this is a lighter band, featuring much less in the. way of "darker" minerals/materials. It resembles Layer "A" rather closely, and is the final "Layer" so-designated in this specimen. It is a periciase (brucite) marble/"calciphyre"?, consisting principally of a crystalline mosaic of calcite and associated. periciase (brucite). Note especially features in evidence on the weathered surfaces of this specimen. Cf. other specimens from elsewhere at the Arctic Chief, especially TM-04-6-9-3, -5. Trace amounts of disseminated dark opaque grains are observed, likely magnetite (note accompanying "rusty" haloes. Also note some pinkish-brownish sub-euhedra {tetrahedra?; _ spinet?}, as welt as perhaps some graphite(?), disseminated throughout this layer. Piece #3: Comprised of some of the "bands/layers" described in the other two pieces of the original specimen. This Piece #3 contains Layers "E, F, G, H, I", per the foregoing observations. The weathered surfaces of this specimen offer a wealth of evidence/effects/information as to textures, mineralogies present. Studied in conjunction with freshly-broken surfaces, coNectively much is available to be gleaned from this specimen. TM-04-6-9-4-5: Specimen a white periciase (brucite) marble. Contains transecting greyish "veins"; linear features which apparently are "healed"/recrystallized "crushn-zones/fractures. These are made up of clearer, coarser-grained calcite than occurs within the crystalline mosaic of the marble per se. Cf. similar marbles, etc.,. from other nearby sample localities at the Arctic Chief -- viz. TM-04-6-9-3, -5, etc. The weathered surfaces are informative as to texture and mineralogy of this specimen. In particular, the presence and nature of the periciase. (brucite) and the calcite, as welt as the relationships among them, are well-displayed (as, in fact, they are .within this specimen as well). Trace amounts of fine-grained black material(s) -- magnetite(?}, graphite(??}, +!-? - - are disseminated throughout the specimen. The"veins"/fractures in the specimen are essentially "linear", and intersect one another at various angles, in a relatively (to other observed specimens at the Arctic Chief) .widely- spaced network. `TM-04-6-9-4-6: This specimen is quite similar to TM-04-6-9-5 (which cf., above), but with. a more closely-spaced network of "veins/fractures/healed crush-zones". A periciase (brucite) 17-A GMC DATA REPORT 3 4 4 Page s~/11~ marble, .with predominant calcite and periclase (brucite}, as well as -trace amounts of disseminated black material(s), which may be magnetite(?)!graphite(?)/+/-?. The weathered surtace of this. specimen is not as welt-developed as on some other similar specimens, hence the. informative "hummocky topography" is not as prominently evident here. TM-04-6-9-4-7: This specimen, together with. the nearby TM-04-6-9-4, -5, -6 specimens,. essentially represent "minor variations on a common theme", as it were. All are rather similar in general appearance, aspect, composition. This ("-7") specimen, however, features a more- closely-spaced network of °veins/fractures/healed crush-zones" (ie., a greaterlhigher "fracture densityn than any of the others). Perhaps interestingly/informatively(?), in the context of the .foregoing, this specimen also affords, perhaps most clearly of the four, a quite. well-developed, mast illustrative, example of the periclase/brucite, and associated calcite, typical of these periclase (brucite} marbles present at the Arctic Chief. The grain-sizes afie relatively larger, here, in this specimen. The minerals are welt better)-developed, their inter-relationships (more)clearty-presented. All fairly evident, both an weathered, as well as freshly-broken, surfaces, while also displayed quite clearly within the specimen. TM-04-6=9-4-8: This specimen is a tight grey periclase (brucite) marble. Consists predominantly of a crystalline mosaic of calcite and periclase (brucite), with irate amounts of black material(s) which may be magnetite(?), graphite(?), +/-?. This specimen is similar to others from nearby localities sampled at the Arctic Chief (cf. in particular TM-04-6~9-3, -4, -5). Some relatively -vague indications of "crushed"!"healed" zones throughout this specimen, manifest as somewhat well-defined linear features, alihough well-developed networks of intersecting °veins'/etc. are not readily apparent. Moderately-developed weathered surfaces display textural, mineralogical, structural features, in complementary fashion to the freshly-broken surfaces elsewhere on this specimen. Not quite the sort of "hummocky topography" as developed on other specimens of similar character, but akin to it. TM-04-6-9-4-9: Light greyish periclase (brucite) marble. Featuring some especially noteworthy examples.. of the periclase-brucite relationship, evident in umistakeable fashion. With some fine examples, variously, of periclase crystals, remnant "cores", with fibrous.. crystalline brucite "rims/whorls" adjacent to/surrounding/pseudomorphous after/replacing the periclase. All within a "marble-textured" .crystalline mosaic consisting of subequal/ predominant calcite as well As per a comment of SMA, this is indeed a "spiendidn example of the periclase (brucite] marble lithology. With all the implications -- petrogenetic, geochemical, geological -- pertaining thereto. The general "greyish" cast of this specimen likely is due to the .significant (though "trace" amount, overall) abundance of very-fins-grained black (graphite?/magnetite??/+/-?) material(s) disseminated throughout. Not in even a minor amount, or so it appears, yet quite evenly-distributed within the specimen. There is at least one "pocket" of sulphide minerals (chatcopyrite?/pyrite???/+/-?), with some at least displaying aspects of eu-subhedrai habit, within the "periclase (brucite) marble"/"rock-forming minerals crystalline mosaic. Suggestive, perhaps, of an "early" formation, likely attendant to the metamorphism of the assemblage. Perhaps due to the presence, pre-metamorphism (cf. as well the apparent[?] presence of ubiquitous. very-fine- grained "graphite"[?) throughout the entire specimen) of an isolated remnant of pre- 18-A GMG DATA REPORT 3 4 ;4 Page. $s/11~ existing,. likely biologically derived, organic matter? le. °organic" material(s) in a precursorial carbonate sediment, etc., etc. ? Several .excellent examples of periclase-cored, brucite-rimmed, eu-subhedrally-outlined pseudomorphous "crystals" :occur not far from this "pocket/patch° of sulphides. "Accident"........... "coincidence"....... or "incident°......... ? Several subparatlel semi-linear/planar "seams/veins" transact this specimen. These occur in a .fairly-widely-spaced "network° of intersecting fractures/shears/"healed crush zones". Though compared to other similar samples from elsewhere at the Arctic Chie#, the "fracture densityn apparent in this specimen might best be termed "moderate". On weathered surfaces, there tends to be a "greenish caste associated with materials presently occupying "care" positions inlwithin periclase --> brucite "composite crystals". Perhaps a weathering phenomenon/product? Possibly related to a ferruginous componentof the original. periclase....... and/or the replacive brucite? Or...... ? Ail-in-all, an exemplary specimen, in a number of ways. TM-04-ti-9-4-t 0: A largish specimen, comprised of hvo types/colors of periclase (brucite) marble, one a dark grey and the other a "whitish" color. The two varieties adjoin one another with. a rather well-definedlsharp contact, of apparent sedimentary nature. There is the decided impression of original differences in composition (+/- texture) between these two variants {ie. a "bedding contacts}. Although some sort of "front"-type contact related to metamorphism/ metasomatism is another (though unlikely, in my opinion) alternative interpretation. The "white/lighter° lithology closely resembles similar-appearing periclase (brucite) marbles encountered at the Arctic Chief (cf. TM-04-6-9-3, -4, -5, etc.) Some fine examples of the mineralogies and textures, in terms of the predominant. calcite and periclase {brucite) phases present, are evident herein. These relationships are also well-illustrated. on weathered surfaces of this specimen. A particularly illustrative "veinlet"/fracture of Linear/planar aspect transacts the darker tithoiogical variant, .abutting against/trending into the lighter adjoining "layer" at essentially 90 degrees. This .feature appears to continue on through the lighter material, on to the "distal° weathered specimen surface, on which a "rusty" zone is manifest, associated with a series of dark fine-grained "specks" (presumably iron-rich; sulphides? and or magnetite?; or....?). Such "veinlfracturen-associated zones at the distal (from the darker-colored rock variant) end of the specimen feature a "string-of-beads'-tike array of black crystals {magnetite?/+/?), with "rusty" portions/subzones/margins/adjacent host rock-staining/ alteration effects manifested. One of these "effects" being apparent staining/alteration of nearby/adjacent minerals. This especially notably affecting "rimsA, and/or "coresp of the periclase --> brucite assembtagelmaterials, which appear to have been particularly susceptible to such "iron-stainingA. Perhaps essentially merely a matter of physical adsorption, etc., of iron-rich fluids by, especially, the generally-fibrous brucite. Though formation of "iron-rich brucitesD due/related to to pre-weathering phenomena are also a possibility. This "string-of-beadsn occurrence is unique to the fracture/crushed-healed zone :best developed at the distal end of the specimen, and best-displayed on the weathered surtace there. The "white" rock variant being etsewherelotherwfse essentially free of other materials, containing .only relatively littleftrace amounts in the way of disseminated dark/bfack material(s) -- .graphite?, +/-?. Appreciable similar-appearing very-fine-grained darkf black material(s) occur(s). in association with the above-described. fracture/healed-crush- zone. Other crystalline material(s) of "rusty" appearance also isfare found in this zone, though, again, this perhaps is actually representing "iron-staining"{?). Or another 19-A GMC DATA REPORT 3 4 ~ Page s9/117 mineral/phase ???. This "crushed zone" features more-coarsely-crystalline calcite,. suggesting a "se~f- healing/recrystallization" genesis, .attendant to fracturing and recrystallization .during and/or subsequent to metamorphism (cf. analogs in similar lithologies at other nearby Arctic Chief locations). This zone persists in linear-planar attitude across the "white" lithology, manifest, for the most part only vaguely, by a trend of sporadic urusiy" specks/material(s), until "emerging" at the distal" end, clearly evident on the weathered rock surfaces there. This zone crosses the "border/contact" between the lighter and the darker lithologies, persisting across the latter to the edge of the specimen. More clearly evident in the darker. lithology, due. to the contrastingly white calcite of which this zone is presently comprised. It immediately/abruptly changes character upon entering the white lithology. Seemingly swallowed up/disappearing, as it were, within this new host rock of somewhat less-dissimilar nature to itself, as compared with the darker lithology. The darker greyer lithology awes this aspect principally to the substantial (verging on being a "minor", rather than a "trace" constituent) amount of fine-grained black material(s) of graphitic"{?) aspect disseminated/scattered throughout this rock type, along (principally, if not actually totally) the margins/boundaries of the rock-forming minerals {viz. calcite, and. perictase [brucite]). There is also an impression of sorrtewhat agreyer" crystals of calcite in this °darker" lithoiogic variant. Though the amount, and widespread dissemination, of the discernible inter-crystalline "graphite"{?)/+/-? material(s) in itself seems sufficient/quite adequate to "explain" the relative darker. colorfcast of this lithology. Presumably representative of an original sediment/sedimentary rock with an appreciable carbonaceous component. [Perhaps less magnesium-rich as well? With possible implications with respect to °magnesian-skarn" development?? Is the perictase (brucite) component of this "darker" lithology less than, equal to, or greater, than in the °whiter" lithology? Good/interesting question....... (?l?). Though the °appearance" under the stereo- microscope suggests subequat proportions of the two principal rock-forming minerals in this darker lithology (in which the viewing constrast is perhaps no better or worse, essentially, than it is in the lighter (ithology{?). [Perhaps a useful subject for. some thin-section work?] TM-04-6-9-4-~ 1 A white perictase (brucite) marble.. A °foot"-specimen; ie. somewhat larger than merely the run-of-the-mill "hand" specimen. Chosen thus for purposes of serving as a "reserve" specimen, for possible future work. "Representative" of other °white marbles" of similar aspect in this portion of .the Arctic Chief. Calcite and perictase (brucite) the principal rock- forming phases, with associated trace amounts of darklblaek material(s) ["graphite"?!+/- ?] somewhat irregularly disseminated throughout. TM-04-6-9-4-12: Another °fooY' specimen. Mostly alight-grey perictase (brucite} marble, with one end of the specimen an apparently .coarser-grained white perictase (brucite} marble. A relatively sharp contact exists between these two litholgic%olor variants. Perhaps most likely representing asedimentary/bedding contact (?). ®r some sort of front", due to metamorphic/metasomatic activities (???}. ®ne obvious fracture/seam/crushed-zone (?) cuts the grey rock, at an other-than- subparallel angle to the white-versus-grey rock contact. The grey rock has some lenses/pods/wisps of coarser-grained carbonate" rock/material(s) in it, here and there. Not as white as the "white marble", but fighter, and coarser-grained, than the "grey" marble. 2a-A GNiG DATA REPORT 3 4 4 Page 90/11 The white marble contains approximately subequa! proportions of the .two principal rock- forming minerals, calcite and (nicely-developed and displayed} periclase (brucite). Trace amounts of "very-very°-fine-grained black. (graphite?/+?-?} and amber (spinet?} grains are disseminated throughout the. white marble. The grey marble shows even better-developed periclase (brucite) features, with excellent examples of brucite "cabbage head" rimslpseudomorphs, periclase .cores, .etc. Some especially nice examples occur on weathered surtaces of the specimen. This grey rock is also quite similar to .numerous ethers from nearby localities examined at the Arctic Chief. The rock- forming calcite in this grey marble here is somewhat finer-grained than its counterpart in the associated white marble in this specimen. The amount of dark-black material(s). disseminated in this grey variant here is a bit/somewhat -- though not alt that much -- greater than in the associated white marble. TM-04-6-9-4-13: A hand specimen. Featuring two variations on the theme of periclase (brucite) marble. One a "white, coarser-grained; more "massive" variant. The other a "less-white°, finer- grained, Less "massive-- "bedded/fayered~ (structurally?) -- variant. The contacf/borderlinter-relationships between these two somewhat ambiguous. in hand specimen. The less-massive .type contains/is cut ay arelatively-closely-spaced network of {apparent) fractures{?), intersecting one another at various low-higher angles (cross- bedding??), Both variants are well-developed periclase {brucite) marbles, similar to others from nearby .localities at the Arctic Chief. Weathered surfaces show this best on the "white" variant here, white the similar relationships are even better-displayed by the other variant, both on weathered and "fresh" surfaces. TM-04-6-9-4-14: A large hand (a "semi-foots?) specimen. Mostly weathered surtaces all .around on this particular specimen. Rock a whitish periclase (brucite) marble/ "calciphyrer?, featuring a podllens/inclusion!(?) of dark grey-black material(s). [Rossibiy of organic composition, origin? le., .perhaps "faunaUfioral" remains?] The black material(s) might(???), alternatively, be "skam" -- ie. garnet(?), +/-pyroxene(?}, +f-?. The weathered surfaces of this whitish rock display, ratheNfairly well, the usual features representative of the periclase (brucite} presenceiretationship, similar to other specimens from nearby localities at the Arctic Chief. TM-04-6-9-4-9 5: A hand specimen. Agrey-whitish periclase (brucite) marbiei"calciphyre°(??). AEI surfaces are moderately weathered. Some "hummocky topography is deve!oped. The weathered surfaces manifest quite well the relict cores of periclase, and the surrounding rinds/sheiislrims ofi brucite pseudomophousiy replacing originally eu-subhedral crystals of periclase°. As noted commonly at this, and other nearby localities at the Arctic Chief. ['Often featuring an "oolitic" aspect. Which ought to be kept in mind when studying features on weathered surfaces. While of course "true" oolitic farms. do in fact occasionallylnot infrequently occur in carbonate racks!] Note a set of intersecting fractures transecting the specimen, aUwith a moderate spacing/density. Note also suggestions of banding/layering subparaliel to the short dimensions of the specimen. Some portions ("bands/IayersD, ie.) of the specimen are "whiter", others less so, ("greyishn, or "pinkish"). A pinkish hue is not uncommon, and. somewhat more apparent in 21-A 6NiC U~TA REPORT 3 4 4 Page 91/117 calcite-rich portions of the rock, due to the darker-greyish material(s) associated with 5urroundeng/adjacent network of fractures. Some of the "pinkishness" may- be due to "rusty" effects of weatheringf+/-?. TM-04-6-9-4-16: This is a "large° hand specimen. Features two varieties of periclase (brucite) marble. One a lighter grey more massive type, the other a darker grey, more "layered/banded/bedded" variant. The contact between the two is fairly-wet! defined, and is in subparallel orientation/attitude with respect to "layering" in the darker variety. The specimen overall seems somewhat "heavyfdense° for its sizefdimensions{?). Avague impression of a certain "unusual heft' to it (?). The layering/etc.{?) of the darker variant reflects original bedding, apparently/probably. Perhaps{?) also a result of "less intense/less thorough" metamorphism (+/- metasomatism) of this portion/lithotagy of the specimen. This darker variety appears to contain a greater proportion of "carbonaceous/graphiticA(?) material Both variants are akin to periclase (brucite) marbles from. other nearby areas at the Arctic Chief. Specimen too large for much examination with the stereo-microscope, while further breaking might destroy some of its "mega" .aspects. Thus "reserved as-is" .for possible future work. TM-04-6-9-4-17-A: Specimen one of three (-"A, -B, -C") from the same sampling site at this "-17" locality. This "-A" specimen an example of "banded skarn". Featuring pyroxene (?), magnetite- bornite-phlogopite-chlorite?-talc?, calcite (pinkish white),. garnet (pinkish-brown), +{?. Pyroxene now strongly altered, with products including "amphibole° (actinolite/ tremotite), "green micaceous° material, likely phlogopite (+!-?), +/-?. Some fibrous "serpentine" also noted. "Relict/actual" pyroxene is not readily apparent, but there might well be some remnants, masked by/associated with the alteration products ubiquitously present with "pyroxene-like" material. Some of the "green micaceous material(s)" isfare a lovely bright to deep green {likely phlogopite [or "clintonite, "mariposite/fuchsite°??]). Not infrequently "fibrous" margins/ edges of this material are variously well-developed ("serpentine/chlorite/talc" ??). The calcite and garnet are intergrown (sub-euhedral) in "pockets", with surrounding "green micaceous material(s)°, magnetite, bornite (some of .which is also intergrown with calcite and garnet). Magnet~e and bornite range sub-euhedral throughout the specimen. The "micaceous° minerals are generally welt-developed sub-euhedra intergrown with magnetite, bornite, etc. Also possibly(??) some hematite{?), quartz, +/-?, associated in very minor amount with the calcite-garnet, +/-?, "pods/lenses/vugs(?)n. Much of this specimen Coi~Sist$ t~5f iiitergrt3ifvn "green rnicaCeoiiS"-tiiagnetiie+%-Uornie. Note an unusual "dull brownish-blackish sub-euhedra! opaque phase/materials in one place. associated with "green micaceous" mineral~~ calcite magnetite which is not "rusty/oxidized") This "unusual/duff"-appearing material resembling perhaps an oxidized/weathered/altered magnetite (but. note the presence of the adiacent "fresh" magnetite). This material somewhat resembtesfhas some intriguing similarities to a specimen labelled "valleriite° presently on display in the Yukon Visitor Centre di_play of minerals found in the Territory. The site of this material in the present sample is on one edge near one of the "tips" of the specimen The "valleriite~~?~" is intergrown with bright "green micaceous° mineral/material for the most part as well as in part intergrown with adj_ ca ent magnetite +/= bornite. in the one noted "occurrence" 22-A GN1C DATA REPORT 3 4 4 Page 92,!117 This specimen, TM-04-6-9-t 7-A, should be compared .with the descriptions of its {complementary) "compatriots", "-17-B, -17-C". Especially with regard to the presence or absence of pyroxene in each, vis-a-vis magnetite. Also as regards the .green micaceous mineral{s)Imaterials(s), etc. TM-04-6-9-4-~7-B: Hand specimen of "ores. Made up of bornite-chalcopyrite-magnetite-"skarn"-, +/-?. Some "rusty". areas on specimen surtaces. Apparent relict black pyroxene (note .cleavages) occurs, though in large part altered to "maskingA green micaceous material(s), +t-. (Cf. sample "-A"). The larger, more "ftamboyantA crystals of "green micaceous mineral(s) seem to be associated with the "ore" minerals. White the smaller, somewhat less-"spectacuiar° mica- tike materials. tend to be foundloccur in association with the "skarn"/pyroxene, where lesser amounts of "ore° minerals are in relatively close proximity (?). In this latter -- ie. the "pyroxene" - "skarn° areas --, the mica-like crystals are smaller, thus (?) .appear "lighter" in "greenishness", with perhaps{?) an additional mineral (white, "very-very- fine-grainedn, perhaps calcite?f amphibole?/ serpentine?f diapside?/ talc??/ forsterite???i+/-?. Though this. may merely represent an optical. "illusion" due to smaller .grain size(?). This grain size effect perhaps the result of "granulization~ due to ,pulverization attendant upon tectoniclstructural deformation? Using. only the stereomicroscope, much of the foregoing remains somewhat "speculative", at best. -The "skarn° portion of this specimen grades into a zone of more coarsely-grained "mica- like° material(s) + relict pyroxene + magnetite +chalcopyrite +bornite, intimately intergrown; with some scattered small vug-like patches of very-very-fine-grained euhedra of calcite("carbonate' of light buff colour (ankerite?/siderite?. Mica-tike material is "retrograded/altered" to .talc(?) and/or serpentine{?), +/- chlorite (??). Minor amount of brownish-reddish garnet, eu-sub-anhedral in aspect, occurs sporadically distributed within the "skarn" material Brownish carbonate -- calcite?; siderite?; ankerite?) -- occurs, similarly, in the "skarn". Such carbonate also occurs, as more. well-developed crystals, in association with "ore", especially magnetite. .How much apparent "pyroxenen is actually magnetite (with cleavage), at -least in parts of this specimen? The. "green micaceous° looks mare like "talc°{?), for the most part, in this "-B" specimen, than it did in specimen "-A". "Green" phlogopite --> talc and/or serpentine {note fibrous edgesfmargins of "mica-like° crystals), as "retrograde" andfar "alteration" effects/results? Magnetite in this specimen is euhedral-subhedrat, massive; bornite sub-euhedral; chalcopyrite is rarety better than anhedral This. specimen is "rustier" than ~-17-A°. The "rustiness' makes the search for "vatleriiteA rather difficult. Only the very occasional posstbiiity was noted; -- all rather "dubious". This specimen, TM-04-6-9-17-B, should be compared with the descriptions of its (complementary) "compatriotsn, "-17-A, -17-C". Especially with regard to the. presence or absence of pyroxene in each, vis-a-vis magnetite. Also as regards the green micaceous mineral(s)/materials(s), etc. TM-04-6-9-4-17-C: A hand specimen. "Banded", with bands of "skarn" (pyroxene, +I-) and of "ore" {magnetite-bornite- +I-?). One surtace of this specimen is "stickensided", with a "skin" of dark-green-black "smeared-out" maftc material(s), perhaps chlorite, +/-, etc.. 23-A GMC DA~~ REPORT. 3 4 4 Page 93/117 .Magnetite occurs as eu-subhedral crystals to anhedral masses, often in association with "green .micaceous mineral(s)/material(s), intergrown with .lesser. bornite, as well as, occasionatty, trace amounts of chalcopyrite (sub-anhedral). The anhedral-subhedral- euhedral developments of each of these sulphide minerals varies from place-to-place within this specimen. The "skarn" bands -- at least some -- appear to actually be "crushed zones/shear. zones/seams" made up of very-fine-grained magnetite and "crushed/recrystailizedn light "green mtcaceousn (viz. phlogopite?, talc?/serpentine?/chlorite?) material(s).. [[Cf. descriptions of specimens TM-04-6-9-4-i 7-A, -B. Which, in light of the foregoing, may merit/require some °reinterpretationn(?).]] Note occasional patches/pods of very-well-developed euhedra of magnetite (the "prismatic magnetite° of SMA?), "micas", and fairly-well-developed crystals of bornite, chalcopyrite. Affording an almost "pegmatitic" aspect, a "vuglike" appearance: One small pod has eu- subhedra[ chalcopyrite surrounded by subhedral, +/-, bornite, with magnetite eu-subhedra surrounding bornite and chalcopyrite. The adjacent "green micaceous" is very-fine-grained (perhaps pulverized! recrystallized?), as part of apparent movementfstructural deformation in this portion of the specimen {throughout the specimen, likely, with recrystallization of euhedralf+!- magnetite and sulphides post(?) these effects on previously-existing °green micaceous" (or, rather, pre-existing pyroxenelforsterite/+I- [?]). A trace amount of carbonate/calcite(?) is associated with this (and others) "pod: Note some occurrences of chalcopyrite (as welt as magnetite, bornite) interleaved/ intergrown with coarse-grained "green micaceous' material{s). (Where is the valleriite?!? Why not here? Perhaps because no clinohumite~?i Where chalcopyrite occurs, the. paragenesis consistently is: chalcopyrite, then bornite, .then magnetite.. Borntte occurring within magnetite sometimes displays a rounded outline (due to the bornite having been partially "resorbed"?). Note some copper "staining" .(light blue green, ie.), .here. and there, on weathered surfaces of this specimen.. Perhaps also some blue {covellite?, chatcosite?, +!-?} on some bornite crystal masses/ surfaces (and also on the rims of some bornite crystals observed on "fresher specimen surfaces). Some "turquoise"-/green-blue- colored material{s) occurs in association with "green micaceous" material(s) in a few places (weathering?/or?). When viewed "end-onn, quite a bit of the °green micaceous° material(s) has this appearance, even in perhaps "fresher views afforded on fractured surfaces. Here and there, atalc/serpentine after/around "green micaceous" crystals relationship does seem apparentlmanifest. See some good examples of the "transition" between very-coarse-grained well-developed crystals of "green micaceous° material(s) and adjacent finer-grained materials. Generally appears to be "gradational", hence perhaps supportive{?) of the "structural. deformation/ distocationA premise/postulate for this state of affairs within this specimen {as well as in the compatriot" specimens _-i7-A, -i7-B'). Patches of buff-fight brown eu-anhedral carbonate minerals} occur here and there, mare often associated with eaarse-grained "zonesn/areas of the specimen. Note a fair amount of apparent evidence (viz. contortion of "mican plates/crystals, "smearing"/shearing?, etc.; perhaps also the coarse-grained pods/patches/zones as subsequent recrystailization effects?), supportive of this deformation/metamorphism(?). Much (but not aN) of the carbonate material{s) mentioned above appears to occur on/within one .particular "shear surface/zone" within the specimen. Some magnetite occurs as masses of perhaps "spheroidalH aspect (or is this appearance actually due, rather, to the "conchoidal° fracture aspect. of this magnetite?), with seemingly "radial prismatic" textures on broken surfaces {ie. of "spheroidal" grains /pods/ 24-A 6MC DATA REPORT 3 4.4 Page 94/117 ";whatever°[?1?)). (vote these especially in association with coarse-grained "green micaceous° crystals. Difficult to recognize possible "valleriite° in this specimen, due to the weathering effects. This specimen is important in terms of many aspects of all three "-17-" specimens Especially so with regard to the suggested/~.ostulated "structural /deformational/ metamorphic° aspects of the coarse-grained <--> fine-grained "green micaceous" material{s~ as well as the presencelabsence of "relict° Qyroxene and the paragenesis of the sulphide minerals and magnetite Each of these three specimens affords unique manifestations and should be considered in com~tementa fashion in any subs went work TM-04-6-9-5-.... TM-04-6-9-5-f An originally large specimen, subsequently broken into "many° pieces. Peridase (brucite) marble. Two variants present in this specimen. One slighter/whitish, somewhat coarser- grained rock, .the other a greyer, denser (?}, fner-grained lithology, A rather subtle, but apparent,"sharpish" bordeNcontact separates the two. Avein/fracture zone{?)/? is subparattel to the latter, and trends along into the "border" between the two variants. -This "border" likely{?) a .sedimentary "contact°, ie. "bedding plane". The nature of the periclase and the brucite, as well as their genetic and textural relationships (brucite pseudomorphousty replacing periclase), are well-displayed, both throughout the specimen, as well as on weathered surfaces. The predominant rock-farming minerals, calcite and periclase {brucite), occur in a crystalline mosaic of typical "marble" texture. Minor/trace amounts of greenish-greyish-brownish fine-grained material(s) disseminated throughout likely are spine!(+/-?). Some similarly disseminated very-fine- grained black material(s) may be graphite(?), and/or magnetite(??). A trace amount of quartz, some appprentiy as sub-euhedral grains, occurs similarly disseminated. TM-04-6-9-5-2: A "salt-and-pepper", "dioritic-looking° specimen. Featuring pyroxene, plagioclase, quartz(?), carbonate(?) materials}, .with lesser proportions of magnetite(?), pyrite, chalcopyrite(?}, and associated epidote(?) veinlets. Amphibole [tremalite/actinolite {?)], serpentine(?), chlori#e(?), +/-?, are observed in association with pyroxene, presumably as alteration phases. The pyroxene tends to occur as stubby, sub-euhdral, prismatic crystals, exhibiting good cleavage, .along with associated alteration minerals. The tatter manifest themselves as rims, sheaths, coatings, "etc., comprised, variously, of amphibole{tremotitic/actinolitic}, chlorite, serpentine(?), talc(?), +;-?, adjacent to quartz+;-Carbonate+/-epidote. Fresh/unaltered pyroxene is black-very dark greenish in color. The sulphides often occur as crystalline masses, aggregates, surrounding, engulfing, and/or replacing pyroxene. Or as discrete eu-subhedral crystals adjacent to such occurrences. Some fine examples of striated pyrite euhedra (including pyritohedra, cubes) are noted, associated with pyroxene, quartz(?), carbonate, +/-epidote, +/-?. Examples of chalcopyrite tetrahedra occur as well. At least two sets of epidote/+/- veinlets are apparent, transecting portions of -the specimen. Might this seemingly "dioritic" rock actually represent "endoskarn° ma#erial, in the sense of Aleksandrov (1 J98)? It appears to feature original "igneous textural, mineralogical, and overall compositional characteristics, Perhaps a representative of "contaminated° magma, from a "carapace/shett° of dioritic character. Portions of which, presumably were 25-A GMC DATA REPORT 3 4 4 Page 95/117 potentially available to intrude into portions of the ad)acent/surrounding country rocks as geological circumstances .may have dictated/permitted/facilitated. Providing magmatic materials for "apophyses" which might serve as metamorphic/metasomatic "facilitators" vis-a-vis especially "susceptible" country rocks such as dolomites, resulting in formation of "skarns~ .and related materials.. Per the concepts presented by Aleksandrov (1998, and etc.). TM-04-6-9-5-3: Specimen similar in aspect to TM-04-6-9-5-1, which cf. White-colored; a periclase (brucite) marble. Predominant rock-forming minerals occurring as a crystalline. mosaic of calcite and periclase (brucite), with associated minor/trace amounts of spinet(?), graphite(??), +/-?, disseminated throughout. the rock. The periclase {brucite) nature, and their genetic/textural relationships, are rather nicely exemplified in this specimen. (Cf. specimens of similar nature, from other nearby sample locations at the Arctic Chief.} As in other similar lithologies from this general area of the Arctic Chief, there. is evidence of at least a moderate (strong?) degree of structural deformation having affected. these rocks. "Crushed/healed zones", fractures, as welt as some "slickenside°-tike feata~res, occur, variously, within these specimens, as especially manifested by the carbonate grains/crystals. Perhaps not "pervasive", but "substantial". TM-04-S-9-5-4: Specimen .represents part of a "slcarn~ zone. Under the stereo-microscope, restricted to working at 30x160x, and only on specimen surfaces (fresh as well as weathered), this specimen is of the "challenging" sort. A "character sample", in the parlance. "skarnn material. Featuring pyroxene, +!-?. With seams of fibrous "serpentine", +f-?, on/along the fractures. Specimen is "fraught" with slickensides, epidote on fractures, etc. Carbonate (calcite?) is abundant in parts of the specimen (ie. the: "marble/calciphyre" lithologies, +/-). The specimen representing a "pyroxene +f- skarn --- forsteritelforsterite-rich zone --- calciphyre" sequence, apparently. Evidence overall of a "magnesian skarnn .situation, in all likelihood. Note traces. of sulphides (pyrite, +/-?) in the "calciphyre" zone.. Also, as wail, in the "forsterite/forsterite-rich" zone, near "seams/shears" featuring/with apparent "serpentineA(?) occurring as prismatic/fibrous eu-subhedra oriented .sub-perpendicularly to "crush zone/fracture wails" of forsterite(?), etc., ad)acent thereto. Epidote present here and there as wail. Similar "serpentine"/+/- occurs within fractures/zones which transact pyroxene and/or other black minerals in "calciphyre", along with associated forsterite, +!-. Pyrite occurs in trace amounts nearby, sometimes as (fresh) cubes. Specimen represents a "retrograde" situationlset of assemblages appare tlv. Complex. As such not insi~.nificant in the 4reater scheme of things here TAil-04-6-9-5-5: Specimen apparently presents a "diorite/endoskarnr to "garnet"(?) to ~pyroxenen skarn contact(s) sequence [??). Featuring a plagioclase-pyroxene- +/- "diorites ("endoskarn"?), similar to TM-04-6- 9-5-2, etc. A thin layer/zone of pinkish-light brownish garnet(?) [rather, zoisite?/clinozoisite?/ epidote?/ ........??] separates the "diorite" from a less-well-defined "skarn"(?) of darker and lighter minerals (viz. pyroxene?, carbonate?, +/-?) A trace amount of .sulphides (pyrite?, +1-?) occurs in this "skarnn zone. Cf. Aleksandrov (1998, & etc.) on "diorites, "endoskarn", "HHP granitoids", etc. 26-A CMC DATA REPORT 3 4 4 Page 96/117 °CM-04-6-9-5-13: A "banded" periclase (brucite) marble specimen. Predominantly consisting of white/fighter-colored bands (most of the specimen) made up predominantly of a crystalline mosaic of the rock-forming minerals, calcite. and periciase (brucite). Wlth some light grey, much thinner, bands/zones/horizons of more-coarsely-crystalline calcite, featuring evidence of deformation of crystals {ie. representing a "crushedU healed/ recrystallized zone within. aformerly/originally more "homogeneous"(?) marble/carbonate rock prototith{?). Trace amounts of black/dark ("micaceous/mica-like"; ie. perhaps graphite?) mineral(s)/material(s) occur disseminated throughout, especially (more prominently?) within the "lighter" portions of the specimen. Such "dark" material(s) somewhat/ appreciably .less-abundant in this specimen than is the case in otherwise quite similar .rocks from nearby sampling; sites at the Arctic Chief. Perhaps the "two types" of marble in this specimen represent different "degrees" of metamorphism/metasomatism, or differing degrees of "susceptibility" thereto; and/ar "locally" differing degrees of structural deformation having occurred -- far various reasons -- within this specimen; and/or actually a case of two originally different lithologies/ proportions of constituents/components{?). Viz. "dolostone" vs. "marble" (??), Etc.......... (?). And/or merely a case of original "sedimentary" bedding??. TM-04-6-10-4...... TM-04-6-10-4-A-1: Part of a "foot" (ie. appreciably larger than a "hand") specimen ("-4-A-"), subsequently broken with a hammer into several smaller ("-A-N........") pieces/sub- specimens. This one a dark rack,. with a vein(s) with attitudes} subparallel to a dominant direction/ orientation of breakage of the specimen. Vein "fresh" <--> "weathered/altered", laterally, on broken specimen surface. Specimen is/seems relatively "dense", "heavy". A dark rock. ivlade up of pyroxene sub-euhedra, black/dark green, with alteration to tremolitic/actinalitic amphibole marginally (+/-talc?, chlorite?, ??}..Some manifestations (warping, bending, of-crystals) of deformational stresses having been experienced within the rock. A minor (+/-) amount of clear-whitish plagioclase(?) occurs intergranular to the. predominant (altered). pyroxene. This plagioclase shows cleavage, and occasional subhedral crystal forms/outlines, with darker/smoky-brownish central cares (perhaps at feast in part quartz?), and clear-whitish grain margins. (Cf. other specimens in the "TlUl-04-6-10-1 <- -> ~" per tes). T ,i ie latter presti~iiabty representing igr'ieouS zoi E ig, though some S©rt ()f "secondary/overgrowth" phenomenon might also be invoked here (viz. with quartz, garnet, +/_?). .Note occurrences of vein(s) of quartz(?}, +/- calcite/carbonate, +!- epidote, with vague to moderately-well-defined .margins, adjacent to the "pyroxene" +/- rock. Iron-stained, as well as with traces of malachite, near a smaPl "pod" of probable chalcopyrite(?) +/- magnetite, +/- ("green calcite"?). Some offshoots here and there of "epidote", +/- "cryptocrystaltine" quartz" (??), into adjacent rock walls. The chalcopyrite crystals are a eu-subhedral, "tarnished", and lie within the vein. There is evidence of shear parallel to the plane of the vein, with "unconformtty" surfaces within the vein. Evidence of "altered"/ "siNcified", +/- "carbonatized"(?)f"epidotized"(??) relict (euhedral, +/-) pyroxene.. grains within the vein. Two "generations" of carbonates, a darker brown ("earlier"?), 27-A GMC DATA REPORT 3 4 4 Page 97/117 and a clear whitish ("later"?), in the veins (??). [And/or magnetite(?), +/-?, with carbonate, quartz(?). Or quartz(brownish)?; then carbonate?]. Origins! pyroxene grains eu-subhedra!, oriented variously {"randomly"?}, with (Quite) subordinate plagioclase, +/-? {including carbonate). Magnetite sub-euhedra disseminated amongst the pyroxene grains. Epidote, quartz, (chalcopyrite?}, carbonate,. (chalcopyrite?), the apparent{???} depositional sequence in veins, from margins in~r/ord. Pseudomorphs of carbonate?Iquartz?/ep'sdote?/+/-? after pyroxene, .with retention of relict crystal outlines, cleavage noted{??), Weathered specimen surfaces suggest "plagioclase", magnetite, +/-quartz, epidote, carbonate, pyroxene do in fact comprise .portions of this specimen, per the above/foregoing "treatise"/"exposition". A sample of "pyroxene skarn"(?), rather than "igneous", ie. ?? TM-04-6-10-4-A-2: Another, larger, broken piece of "-4-A-.....". The "other half', actually of a piece broken from "-4-A-1...." originally. "Same as its mate". TM-04-6-10-4-A-3: A larger broken piece. Observe sub-euhedral outlines of "pyroxene"(?} crystals (12 mm, +/-, and smaller) here and there; "vein/seam" of carbonate(?), +/-. The large "pyroxene" grains. show 87133-degree cleavages (?), are black-dark green, could be altered to hornblende(??), and then to tremolitic/actinolitic amphibole, marginally (+/-talc?/+/-?), The eu-subhedra abut one. another at various (--> 30 degrees) angles ("glomeroporphyritic"/"blasto-"), originally???). Sample is "seamed", with epidote, quartz(?), carbonate, +/- "opaques~ (???). TM-04-6-10-4-A-4: t_argest broken piece. Calcite euhedra in one location associated with a "vein". "Color index" of this sample = 60+ (to "++"}. Calcite (cleavage remnants) =16 mm, `+/-. "Much" of the "late"-clear-whitish material in the specimen probably is calcite(?). Though some is likely plagioclase (?), +/-?. "Seam/vein" is quartz and calcite, +/- epidote, +/-.. Perhaps (?) most likely (??) an "altered/retrograded" "endoskarn"?? pyroxene and plagioclase rock ("exoskarn"?), with magnetite, veined/seamed with calcite+/-quartz+/- epidote+/-magnetite(??)+/_?. Possibly (?} trace of very-tine-grained "opaques"; viz. "sulphides" (and/or "graphite" ?/ /+1-/or "disrupted" magnetite (??), disseminated throughout the specimen (??). TM-04-6-10-4-B-1: Once part of an original "foot" specimen, now broken into several pieces. These labelled Note euhedral (well-developed) prismatic pyroxene (clinopyroxene?} "ghosts" on a (freshly-broken) fractured surface, which also contains sulphides. The "ghosts" now pseudomorphed --> hornblende(?) +/-?. Carbonate euhedra (and also some less-weCl- developed), on the opposite (also freshly-broken) specimen surface (pinkish-buff-whitish), with sulphides present as well. Note similar "ghost" features in other. "dioritic" rocks in this general area. Are these originally igneous in origin, or metamorphic/metasomatic? Scattered eu-subhedra (and less-well-developed} of sulphides ("mol~bdenite"? galena? magnetite~~} on specimen surfaces Specimen broke readily along these surtaces, thus they. are "zones of weakness", +f- "zone(s)" of structural significance within this, as well. as the original larger, specimen. Featuring mineralizationlalteration associated with them. 28-A GMC DATA REPORT 3 4 4 Page 9s/117" Apparently featuring euhedral crvstals/platelets of molvbdenite(?) -- hexagonal seemingly opaque. shiny. moderately "looserleaved". Or, alternatively, (??~, some sort of peculiarly "blackish/bluish". shiny to "dull-appearing" black mica (viz. biotite, phlogopite (??): or graphite(??}. Or "smeared" galena. +/-?. A penknife point succeeded in °peeling" a curling "shaving" of a layer. from one or these hexagonal crystals; ie. "looks metallic"(?). Host rock/specimen overall: Features eu-subhedral pyroxene{?} --> "amphibole" .initially hornblende, then subsequently --> tremolitic/actinofitic variety. Plagioclase is another principal mineral present in .this specimen, occurring as eu-sub-anhedral clear- whitish grains. Minor euhedral and less-well developed quartz(?) is also present. Thus the rock .might be considered to be aquartz-bearing/quartz diorite, with an "igneous-like"(?) texture of intergrown crystals. Evidence of a moderate{?) degree of structural deformation throughout the specimen, with some "veinfets" along semi-planar "shear/fracture" surfaces, which often feature. very- fine-grained carbonate (calcite?} +/- quartz(?), +/-?. Molybdenite/? is .essentially restricted, as far as can be discerned fn this hand specimen, to one zone/fracture/shear (??): Relative proportions of pyroxene/etc. vs. plagioclase seem fo vary within the. specimen ("banding"?). The larger-scale "ghosts" mentioned above are not readily evident as such at 30x magnification, likely due to the replacing/pseudomorphing materials ("amphiboles", +/-) "masking/confusing/obfuscating" aspects of the original pyroxene crystals. Trace amounts of epidote occur here and there. especially in the "zone" which features the apparent molybdenite('?). These "molybdenite" euhedra are half-again or so as large as adjacent "pyroxene?" --> "amphiboles". +/-. grains. The "molybdenite" grains measure on the order of 3.0 mm in "width" of hexagonal plates. The "other/whiter" side of this specimen features similar "mal~rbdenite". more-wide) faced/spread across the hammer-broken fracture surface. and they are of similar {ie. 3.0 mm~ and smallerl "width" as their counterparts an the other "darker" surface of the specimen. A penknife point drawn across a surface of one of these "platelets" readily leaves a rog_ ove (?). Though this material seems uncommonly "well-crystallized" for "graphite". Though in reflected oblique illumination at 30x magnification it also looks perhaps a "bft too black?" for .molybdenite(??). These "enigmatic" opaques are intergrown/occur with "pyroxene" --> "amphiboles". +/-, and/or plagioclase. on this surface. Occasionally "interleaved" with "tremolitic/actinofitic amphibole"/+/-. One massive accumulation of "molybdenite" crystals seems to have "reacted with/been altered to" a pale yellow-buff "box-work/network" of prismatic/iathlike crystalline affect ,(with voids). Suggesting n• erhaps the "parent" material in this instance was not graphite/carbon". but. rather. "something else"/a sulphide viz. molydenite: and/or?~ le. molybdenite/siifphide --> a SCiffate. carbui~ate, +/- etC. ~?~. This Occurrei~Ce Iles within an area of plagioclase (+/- carbonate?~, and _pyroxene" --> "amphiboles". +/-. not far from a "zone"/"veinlet" featuring rather well-crystallized epidote/+/-?. White-pink materials on this specimen surface are carbonate (calcite?), quartz, plagioclase, +f-?• The "ghosts" (1.2 mm and smaller) of "pyroxene" (?) euhedra mentioned above are apparently on the "darker .surface of this specimen. They are now comprised of a pseudomorphous assemblage. of "amphiboles" (viz. hornblende, followed by "tremolitic/actinofitic" material). For the most part, these occur as fine prismatic crystals, mare or less oriented in keeping with that of the "original" pyroxene crystals. There are, however, orientations at odds with this. This latter effect may be more apparent than .real, 29-A G~~ u~t~A REPORT 3 4 4 Page 99J117 however, since the "original" pyroxene(?) crystals occur in various orientations {even presently, within the "ghosts" -- ie. the "ghosts" perhaps not igneous in origin, but, .rather "--blastic", due to "other-than-igneous" -- ie. metamorphicfinetasomatic -- circumstances. "Growth/replacement" (???). In places, such as shown on this surface/portion of the overall "-4-B-....n sample as a whole, the mineralogy, +l- the texture, .appear to be more a "gabbroic"?/"skarnoid" type of affair (?!?}. The "original" pyroxene(?) crystals (black, shiny} .are often seen as representing "books"/"patches" of "platelets" -- ie. "mica-like"{?) -- (biotite/phfogopitef???). This appearance might(??} be the. result of "alteration", andfor "breaking" with hammer, of traces of pyroxene cleavages on pyroxene "prism" faces {???). Cleavages, "ghost" morphology/outlines are, however, apparently indeed "pyroxene-tike" (?). The "ghost" outlines are only apparent without magnification, and are not readily discerned at 30x. ' It might be conceived that the rock originally was more. akin to a "pyroxenite/gabbro" ("meladiorite"?) than a "diorite"; perhaps even more likely {?) a "pyroxene skarn", retrograded, fractured, .mineralized, etc.. (?). It dotes in_fact_seem_that the_aaparent "molvbdenite" is. most likely -- though reauirin further confirmation -- gust that Per its metalifc luster and other characteristics its color its observed apparent "boxwork/ne#work" alteration and other attributes Although "smeared-out" occurrences of sulphides such as galena. etc., remain possibilities yet to be dismissed. While "graphite" seems perhaps the least likely candidate. A!I-in-all. a most interesting specimen. if perhaps remaining a bit "enigmatic". at the preliminary level of "triage/analysis" performed here. Petrographic scope time.......!!! TM-04-6-10-4-B-2: This sample ("-2") is from another (opposite) end of the larger .specimen ("-4-B-.....") from the previously-discussed "TiVl-04-6-10-4-B-1 " sample (which cf.). Sample "-2" shows two rather distinct (in mega-appearance) apparent ifthogies, one dark grey-black, with a color index of about 50+; the other one a lighter grey-green, though also with a color index of about 50+, if the "green" material(s) isfare considered "mafic". A moderately "sharp" border separates these two, Note same "ghosts/mega-crystals-blasts-phenocrysts" (?), on the order of 1.2 cm and smaller. These appear to be somewhat akin to similar features observed in sample "-1 ". However those in the present sample have perhaps(?)amore "hornblende-like" aspect (?) than the apparent "pyroxene"(?) analogs in "-1 ". There is actually a vague indication of "bandingftayering", with "bands" of `black" versus "grey-green" alternating. Each band on the order of 1 to 3 cm in apparent thickness, as viewed on the specimen surface. Two major broken specimen surfaces, one "fresh" ("F"), the other weathered ("W"). "F": Presents some fine examples of euhedral pyroxene (with the distinctive cleavages), surrounded by rims of tremoNtic/actinolitic amphibole, +/-, within/adjacent to sub- euhedral clear-whitish plagioclase. Some of the plagioclase is altered, variously, to {apparently) epidote, +/-, in places. A "banded/layered" specimen, with darker ("pyroxene-rich") versus fighter-greenish- (plagfoclase+/-epidote, +t-? - richer) "zones/bandsn. A few thin planar "seams/veinlets" transect the specimen, with associated °more intense" 30-A GMC DATA REPORT 3 4 4 Page loo/11~ development of epidote/epidotization of adjacent plagioclase, as well as some concentrations of FeOfOH (now,. at present) material(s). Trace amounts of "magnetite°(?)/+/-"limonite" are scattered throughout the specimen as weft. A "plagioclase +pyroxene (now --> "amphibolesn, +l-?) rock". "Diorite, meta-diorite, gabbro, etc..(?). "Igneous"? Ora "pyroxene-plagioclase "skarn/skarnoid°?? " lftJ H . .Suggestions (viz, cavities,. "drusy surface") of carbonate on weathered surface of specimen. Trace of "molybdenite"(?)/"graphite"(??)/"smeared-out° sulphides. +1- ? /l 'AND/ OR....... . ? on surface This surface is the extreme opposite end of the specimen from the specimen TM-04-6-10-4-B-1 {which cf.}_ This {moderately} weathered surface features much "white" -- though with apparent "iron-staining" -- material {"crust: andlor "fracture surfacelseamlveinlet"?1T. The "molybdenite°{?) occurs here and there. associated with white material( ie plagioclase +I- ouartz(?) +I- carbonate? +I-?}. as eu-subhedra. similar to that noted on the "-4-B-1" specimen. The "molybdenite"{? is fresh unweathered (?• perhaps rather "graphite. thus??). Traces of eu-subhedral "rusty" seeming opaque magnetite?~ sulphide[s]}rains occur on this surface of the specimen. Some pyroxene crystals show slight incipient weathering {?) --> "rusty° .material(s). Note another "ghost" .pyroxene, about i .5 cm in maximum observed dimension, with euhedral crystal outtinefshape, weathering(altering -->?. NotefAsidel--- Re/ "diorites", etc._ Esq, in the Whitehorse Cooaer Belt. +I- "Igneous° diorites? Vs. "pyroxene-plagioclase" rocks; esp. as per Aleksandrov (1998, & other papers) ?Criteria for distinction? Endoskarns....... Exoskarns....... Skarnoids.......... Contamination........ Reaction......... Assimila#ion......... Melting......:.. (esp. "of country/host rocks"; and/or "skarn°......:. } "Meta-diorites°........... "Gabbroic rocks° -- compositionally (mineralogy, chemistry); texturally; modesfloci of occurence; etc. (?} "Meta", "Meta'd", "Meta", -- "diorites". "Granitics°......... "Super-heat".......... "High-heat-producingn (HHP) "granite/granitics magmas/melts......... (Cf. Aleksandrov, esp. his "St. Austell"/HHP paper, and his1998 book). TM-04-6-10-4-B-3: Similar to "TM-04-6-10-4-8-1 ". of .which the present specimen, "-3", is the larger "parent" portion, broken in turn from the largest (in "reserve") "foot" specimen ("-4-B- ....... j. YVl161G. ~Q5 ! mentivoled to Sii7i Coyne) an evei! iaryer, "per~uititndte",.patent resides(ed) along the "Mt. McIntyre"{?) road (on the "southish" side of the .road), about 0.3 miles uphill from the. junction of this road with the °road/two-track" to the top of the Arctic Chief {west) pit north rim (cf. field notes). The present specimen ("B-3") features on the order of 3-5°!0 "molybdenite" (?)/"graphite"(??}/"smeared" other material(s). viz. galena. other sulphides. etc. (??) located on the "fresh" fracture surface ("F"} of the specimen, which surface is the "mate° to that/the similar one on specimen "-i" which cf.}. This surface "~ F a ,~, is intersected/transected by a number of moderately-spaced fractures cutting across it at high (---> 90 degrees) angles. These latter fractures are not obviously "mineralized". More akin to "cleavage" in aspect (?}; "fate°, hence, presumably. The opposite side of the specimen ("W") is moderately weathered, with appreciable whitish 31-A GMC DATA REPORT 3 4 4 Page 1.01/117 +/- "rusty" material(s), as well as slightly-moderately weathered pyroxene, +/-. These two surfaces, "W" and "F", are subparallel, with several variously-well-developed "seams/veintetsffractures" subparaltel to them, within the specimen. Also .note several "veinlets", with associated "whitish" materials}, trending at high angles to both the "W" and "F" and the "cleavage-like" trendsffractures. In essence, mare or less a "three- dimensional" network. A "cross section" of a "weathering profile" at the larger butt end of the specimen has much to offer in terms of elucidation of mineraiogies and textures of this specimen. The "cleavage-like" fractures may have at least some associated quartz (ie. "silicified"), +/- traces of iron-bearing material{s}. The "molybdenite"(?) crystalsfplatelets seem to have a "coherency" as individual sub- platy flakes suggestive of a "metallic". rather than "graphitic/carbonaceous". character (?). Though. as well.. there may well be some (smaller, disseminated) grains/platelets/etc. of graphitelcarbonaceous material present on this fracture surface (??}. Some of the"molybdenite" (?~ crystals/platelets are on the order of 4.0 mm (±!-~ in maximum dimension of the hexagonal surfaces. The whitelwhitish (sometimes slightly "rusty/ferruginous"?) material(s) associated with these "molybdenite" ~) grains may be I~agioclase/quartz(?}/carbonate(?)/+/-?. Epidote is not uncommon in proximity as well. Also some copper-bearing sulphides viz. cha[copyrite. +/ bornite. +!-?) occur sporadically on this fracture surface (associated with carbonate quartz' +t-~) Some green {malachite. +/-) material(s) associated as, presumably. alteration and/or weathering-. products. These sulphides are eu-subhedrai, as welt as less-well-developed. Seen best on one edge of the ~ecimen near the "wedge-end" of the specimen Some very-welt-developed "tetragonal-like" euhedra noted here. Some "molybdenite"(?) is associated with/intergrown with "tremolitic-actinolitic" amphibole+/-. and relict pyroxend. There is a "chlorite-like green" cast to some of the "whitish-clear" mineral(s) (viz. quartz?, carbonate?. plagioclase?/+/-?}. akin to an "internal dusting" of inclusions of "extremely fine-drained" green materials) [??,. "Copper--"???. "W". Surface is moderately weathered. Evidence of weathering of mafics (pyroxene --> utremolitic/acinolitic" amphibole, +/- ....., with "drusy" very-fine-grained .crystals of bright --"epidote"-- green eu-subhedra, seen on relict pyroxene crystals, etc, ---> surficiaf crust on weathered surface of specimen; more or less "ubiquitous"). Also weathering of carbonate, +/- plagioclase, is evident. Numerous holes, cavities are noted, though there seems. to be no (other)compelling .evidence of "weathered-out" sulphides, or magnetite {?). All-in all, an interesting specimen. Es ep cially with regard to the chalcopyrite +/-bornite + malachite + "molybdenite"(?~ associated on the "F" surface. TM-04-6-10-5: "Dioritic" (?) rock. Sulphides. and trace malachite, on a "readily broken" (with a hamm_e_~surface ("fracture"?). Blebs/blobs/patches of -black material s) associated with these su! hides. Specimen has a "granitic" aspect, overall, with vague "bandingflayering" in places.. A "salt and pepper" texture, megascopically. "Rusty" weathered surfaces. staining near sulphides. Chalcopvrite. with associated white (carbonate?),_ red-brown _ _(hematite?~_aarnet??1~ yellow-green (eoidot~, clear-vitreous 32-A GMC DATA REPORT 3 4 4 Page lot/il~ (quartz??/carbonate??ffeddspar??) material( Chaicopyrite is eu-subhedral with occasional weathered(?}/altered(?) associated malachite hematite{~}/mercury-bearing rnineral(~I???j. This chalcopyrite. +/-. assemblage is essentially restricted to a planar zone of relatively small thickness with evidence of structural movement within this zone (slickensided features. alteration]. Essentially chalcopkrite~ +/pyrite(?), some bornite (? perhaps -- -> hematite?. +!- malachite. etc. ~. at least in part ?~. Note other "veinlets" of epidote(?), quartz(?), feldspar(?}, +/-?, which transect this zone, here and there. -Some such feature apparent very-fine-grained carbonate(?) of pinkish. hue. Black hornblendic(?) amphibole, similar to that found .less-intensely altered in the surrounding "country rockA of this specimen, is, in this zone, moderately/strongly altered; peripherally and along cleavages, to a fight green prismatic "tremolitic/actinolitic' amphibole, +/-?. .The "host. rock/dioritefendoskarn/exoskarn°(?) is made up principally of clear white plagioclase (?), and dark green to black amphibole (note cleavages)/+/- "pyroxene". The latter "mafic(s)" .show(s) various degrees of "alterationp ---> "tremolitic/actinolitic" amphibole; but, for the most part, less intensely so than is the case within the sulphide- bearing zone. Eu-subhedral magnetite is an .important third constituent .mineral in this rock. Plagioclase, pyroxene{??)/amphibole (hornblende?, +!-?), are eu-subhedral, intergrown in an apparent (?) "igneous texture ("granitoid/dioriticn}, of medium-fine grain size, more or less equigranular constituent phases. Some epidote alteration of/marginal to/within plagioclase, and/or "amphibole(s)". Also +!- some "flakesfspecksn of magnetite(?)/ galena(??)lmolybdenite{???)/graphite(????) on "dioritic rock proximal to the sulphide-bearing "zones. Some lozenge-shaped amber eu-subhedra within the rock might be sphene (?)I+/-?, in trace amount. "Country rock" of "dioritic" aspect/flavour, mineralogically and texturally (?). [[However --- "genesis" is another matter. Especially given/in the context of the local-areal-regional geological setting/environment.jj Perhapsflikely (?) an example here of the not. unusual "dioritic" border! margint carapace/shell associated with "graniticn intrusive suites in many places elsewhere. Apparent examples of such too numerous to do more than allude to .here,. in this report. Cf. also Aleksandrov, 1998, and other publications; especially his "HHP° paper at the St. Austell conclave. Implications for the Arctic Chief? For the Whitehorse arealCopper Belt? Regionally? Cf. also Moorhouse, 1959, regarding diorite, especially page 244 regarding hornblende after pyroxene morphology, etc.; also pp. 256-301. "A lot of lore°, in Moorhouse (Hogarth, pers. comm.). At a location on one edge/corner of this specimen note one very-well-developed eight-sided in part euhedral crystal (pyroxene originally) Replaced by epidote in the center and "malachiten at the crystal margin with some. relict "pyroxene" remaining in the central core. Further, as regards the nature of the dark/black "blebs/blobs/patches" seen megascopically on the surface of the specimen, near the sulphides. "Megasopicaliy" they have a "blasto"-crystalline aspect, with seemingly a "metamorphicn equivalent of "poikititic" texture (ie. "paikilobiastic"}. i/iz. the amphibole?Ihornblende??lor.......... ?, with "inclusions" of "plagioclase", "pyroxene", +/-?. They seem to be, rather, "compositesfl of variously-oriented eu-subf~edra! pyroxene, which has been moderately "altered" --> "tremoliticlactinolitic" amphibole, {+/-). 33-A GMC DATA REPORT 3 4 4 Page 103/117 Seemingly via an intermediate "hornblende" step/stage. The pyroxene having a decidedly "black, shiny, hornblende-like" appearance to it. le. (?) :pyroxene --> "hornblendic amphibole" ---> "tremoliticlactinolitic" amphibole, +/-. Was the hornblende originally of igneous ("dioritic"?) parentage, initially? Subsequently pseudomorphed to pyroxene, via change (increase?) of temperature, and/or other effects related to changing pressure, composition conditions? With subsequent "retrograding/alteration" resulting in formation of tremoliticlactinolitic amphibole, +/-? Some of the outlines of the "mega" car rstals abut chaicop~rrite +l- carnet? +1-?, as though the~C crystallized "side-by-side" (??). Or rather sulphides "quartz"~ epidote carbonate +/- "replacive" of "pyroxene" TM-Q4-6-~t ~-6-1 An outcrop specimen. A "salt and pepper" rock. "Dioritic"(?). Two variants noted in the specimen. The "contact/border" between them is relatively distinct/sharp. One is afine-grained equigranular rock, featuring apparent "pyroxene" feu-subhedrat} and plagioclase. "Pyroxene" features rams/borders of apparent "tremolitic/actinoiitic" amphibole composition. These "pyroxene" grains occur intergrown with sub-anhedral plagioclase, +/- quartz{?), +/-?. Color index = 4Q+; ie. "diorite/meladiorite" (?). Trace of mafybdenite(~faraphite(w~/magnetite(?} Molybdenitevf"smeared" galena or other sutphides~/"giant" magnetites occurs} associated with carbonate at/near the margin/contact/bvundary between the fine-grained and medium-grained variants of this specimen. Likely {?) magnetite, but might be "mica", viz. biotite, phlogopite {?). Persistent along this "contact", in trace amounts. Apparent magnetite euhedra noted. Note also some oxidation products {"rusty", +/- 4mm in size) associated with this "contact" zone (and elsewhere, too), where the fresh and weathered surfaces of the specimen meet. This material{s) persist{s) .throughout the "medium-grained" portion of .the specimen. The other variant is amedium-grained rock,with large black eu-subhedral crystals of "pyroxene"(?), within fighter {plagioclase?) material(s). One {the largest noted) euhedra! prismatic "pyroxene" crystal is 14 mm in maximum observed dimension; others are in the range of 7 mm and smaller. The weathered surface of this medium-grained rock shows the major mineral constituents "in a different light", as it were. Consisting of apparent quartz, plagioclase, carbonate, pyroxene (with. "amphiboles"), magnetite, green euhedra of spines(?)/??, and perhaps(?.) some molybdenite(~ Some eu- subhedral clear amber crystals (sptnel?/+f-??) occur in this rock type, associated with (GlCene to IVt:lase, +/- 1JCillz. )rake l~l alnet '??~ nGLed, aj vel 'fine- lalned, 1ed- pY p g q g l 1 'r g amber, eu-subhedra, +/-, associated with pyroxene. Might the pyroxene "euhedra" originally been "glomero-porphyritic/-phenocrystic" groups of crystals, now "altered"/whatever --> "urafite" (viz. hornblende? --> tremolitic/actinoiitic amphibole/+f-epidote/+/-phlogopite or biotite in places? The "mega- euhdrat" outlines now consist of a mass of variously-oriented eu-subhedrat relict "pyroxene" crystals --> "amphibole{s)" --> +/-. Similar to relationships: observed in "diorite-like" specimens from TM-04-6-10-4, & -5 (which cf.). Two kinds/generations of plagioclase noted. An "earlier", often eu-subhedral, .clear but "brownish" variety. This surrounded by a more abundant "whitish" variety (?). (The "brownish" could(?) actually be "later" .than the "whitish" (???).] The "brownish" ranges from euhedra) <--> "rounded". Perhaps these relationships, actually/merely. representing a 34-A GMC DATA REPORT 3 4 4 Page X04/117 matter of .zoning in plagioclase (?), from "dustyfsmoky"/altered cores --> "whitish" rims (??). Likely (?), or so it appears, in some views. le. "zoned» plagioclase. [Perhaps "Gkeiy so"; but not "assuredly so". As is the case in most matters .geologic -- and. otherwise. Cf. Smith, Spry, etc.] Does this suggesUindicate/estabtish/demonstrate!"prove'' the "igneous" nature of this plagioclase? .........+/-the rock? At (east during the crystallization of the plagioclase adjacent to/around the "pyroxene" eu-subhedra, etc. (?}. !e. crystallization from a melt, "contaminated" or otherwise (?). With attendant/presumed implications as to "dldeltaT", "HHP", etc., .per Ateksandrov (1998, and other publications; especially his "St. Austell" paper). le. not a "plagioclase-pyroxene rock" as a metamorphic/metasomatic product. But, rather, aportion/variant (perhaps/likely "contaminated"} of the la "main magma" body (?}- [Aside/question: can/does a "contaminated", perhaps/likely(?) less-basic, melt crystaiHze medium-fine-grained eu-subhedral pyroxene, plagioclase, +/-, at lower temperatures than the experimentally-"demonstrated" phase relationships/mineral stabilities "regime" (at "thermodynamic equilibrium' ; ie. (??). Perhaps as a "non- equilibrium" "quench phase/"over (or under) -shooting" sort of thing (??). "Reaction/assimilation" as a "type" of metamorphism? Cf. stabilities/assemblages per various PTC's.j One freshly broken surface on the specimen shows some minor iron-staining at an edge where. the surface adjoins one of the other, weathered, surfaces of the specimen. TIUI-04-6-10-6-2: A hand specimen now broken into six pieces. "Float" sample. One fracture noted cutting this specimen. Vaguely-defined "planar" .seams occur subparattei to this, or at +/- 45"degrees to it Specimen displays a "salt and pepper" texture, megascopicalty. The lighter grains showing a "pinkish" cast, the .darker ones agrey-green aspect. (Altered/metamorphosed- metasomatized?). Light green material "diopside"? An "altered pyroxene", ---> "tremoliticfactinolitic" amphibole, +/-? Crystals displaying good outlines suggestive of "pyroxene". Now made up of crystalline material(s) with some apparent relicUvestigial "87-93 degrees" cleavages, but with overall. color aspect of "diopside/tremolite-actinolite" (?). Some of these crystals are clearly eight-sided in outline; prismatic forms are. displayed as well "Pinkish" matelrial(s) ~~originaity/still(?) plagioclase .(likely). Pink representing alteration --> tiltnoZOf.Slle/L~Jtslte/IYI11-epldote/+%-?. Now a subtle "rose gdiaiiZ" Cvtor, iri piaCCS {d lie to zoning, or to thickness of viewed crystal, etc.?). Though at least some of this pink material might actually be carbonate; some might be quartz(?). Traces of apparent zoning (?), with brownish cores and lighter rims. Could (?) be zoned garnet, rather than plagioclase (?). Occasional scattered crystals/patches of dark brown-black. "graphite-like-looking" material(s), especially associated with "plagioclase". Traces of light yellow-green epidote(?) are similarly .associated, as eu-subhedral crystals. Also note some. amber-brownish eu- subhedra of spinet(?}/garnet{??)/or?. Possibly (?) also some light red-pinkish garnet(?) here and there. Also (appreciable) eu-subhedral magnetite (?)/?, as well as phtogopite(?)/graphite{?)/sulphides, disseminated, here and there. 35-A AMC DATA REPORT 3 4 4 Page 105/117 Note a few "prominent" interns[ fractures/shears, .which intersect at various angles, in a moderately-spaced "network". Some "siickensided" features also.. noted in association with- these. Lithology(ies) now a pyroxene ("altered" --> "amphiboles°, +/-) -plagioclase -garnet - magnetite (minor) -carbonate - +/- quartz? - +!-? "rock", with textural variants. An "altered/retrograded/{talc)-skarned" rock {?). Vtfhich could have had a "dioritic-gabbroic" protolith. At least some of the "pinkish" material could be carbonate. There are some masses/pods of magnetite(?), here and there, as well as the disseminated eu-subhedra. Weathered specimen surfaces .afford much. useful information/perspective regarding this specimen. The "light-green" material(s) does seem to be (altered) "pyroxeneM (now diopside[?], and/or "tremotitic/actinoliticn amphibole(s), +l-), based on the nature of observed crystal shapes/outlines, and cleavages, especially when .viewed on weathered {moderately+) specimen surfaces. The pinkish-whitish euhedra appear to be feldspar, presumably plagioclase,. as similarly viewed on weathered specimen surfaces. Occasional bright green six-sided crystals are probably epidote. Also noted. are variously rounded/weathered apparent euhedra) crystals of "magnetite". Weathered specimen surfaces are informative at 30x/60x viewing, especially .with the stereomicroscope. TM-04-6-~ 0-8-A: Hand specimen. "Ore". Massive specimen of magnetite, with scattered. patches of serpentine{?) .[greenish, to bullish-yellow on weathered surfaces). Traces of copper-staining (light blue-green) on some fracture surtaces. TM-04-8-9-2-Z: Garnet (reddish-brownish) and pyroxene (dark green/black) "skarn°, with crystalline calcite (orange-pink), +/-. (Cf. similar specimens TM-81-7-30-1 & -2.) "Typical skarn", .sent to SMA January 2005. Cf. SMA comments. TM-04-~ 0-12-.... TM-04-10-12-22-A-1 01 : Massive chatcopyrise, magnetise, +/- bornise; with associated pyroxene, calcite(?), quartz{?), malachite (featuring some nice acicular crystals), serpentine(?), +/-?. TM-04-1 0-1 2-22-A-1 02: Massive magnetite-bornite-chatcopyrite, +/- calcite(?), serpentine{?), quartz(?). TM-04-1 0-1 2-22-A-1 03: Green "mica" (phiogopite, presumably); magnetite, bornite, pyroxene(?), serpentine(?), calcite, quartz(?), +/-?. TM-04-1 0-1 2-22-A-1 07: Massive magnetite, with coarser crystals of bornite(?) [with associated azurite/malachite 36-A GMC DATA REPORT 3 4 4 Page 106/11 on the weathered side of the specimen). Also crystals of forsterite(?)/ --> serpentine(?). Also some calcite(?) and/or quartz(?). A small specimen, but one with some interesting textural relationships. TM-04-1 0-1 2-22-A-1 1 2: A float" specimen from the. ~-22-A" area. Note s©me subtle banding" in mega-view. Periclase (brucite) marble. Predominant rock-forming calcite and periclase (brucite). Trace amounts of black opaque mineral(s): magnetite(?), ludwigite/vonsenite(??~, +/_?. Also some spinet(?), forsterite(?). TM-04-1 0-1 2-22-A-1 13: A carbonate rock specimen. °Fooat" from the "-22-A" area. Features two. types of carbonate rocks, one white, the other grey.. Both peric{ase (brucite} marble, 6ithologically. The periclase-brucite relationships are especially evident an the weathered specimen surface. Weathered surface also shows trace amounts of black opaque mineral(s), and some sulphides (pyrite?land/or??. [Also perhaps~t? motvbdenite(?~~] TM-04-1 0-1 2-22-A-1 20: Specimen from a LARGE chunk of ore material at locality °-22-A". Comprised of magnetite-bornite-phlogopite- ,+/-?. Note varying grain sizes of crystalline phlogopite. TM-04-10-12-22-A-1 21 Specimen from a LARGE "boulder"/chunk of ore material in the "-22" locale. On the °bench"/rim of the south side of, and above, the entrance cut at the Arctic Chief (west} pit. Specimen consists of magnetite-phlogopite-bornite, +f-?. TM-04-10-1 2-22-A-1 22: Specimen from the same general locality as the "-22-A-121° sample, above. Consists of magnetite-bornite-chalcopyrite, with much associated phlogopite as well. (+/_?), TM-04-10-12-22-A-1 23: Specimen from the same general locality as the °-22-A-121" sample, above. Consists of pyroxene(?)-magnetite-bornite-chalcopyrite-phlogopite(?)- +1-?. TM-04-10-1 2-22-A-1 24: Specimen from the same general locality as the "-22-A-121" sample, above. Consists of pyroxene(?)-phlogopite-magnetite-bornite-chalcopyrite- +/-?. TM-04-10-1 2-22-A-1 25: Specimen from the ^sa:re general local -y as the °-22-A-121" sa~..ple, abfii%e. Consists of pyroxene(?)-phlogopite-magnetite-bornite-chalcopyrite- +/-?. TM-04-1 0-1 2-22-A-1 26: Specimen from the same general locality as the "-22-A-121 " sample, above. Specimen is `banded", with opaques versus non-opaques: magnetite-bornite-chalcopyrite; forsterite(?)- calcite(??)- +/-?. TM-04-i 0-1 2-22-A-1 27: Specimen from the same general locality as the °-22-A-121" sample, above. Consists of phlogopite-magnetite-bornite- +/-?. 37-A GMC DATA REPORT 3 4 4 Page log/ll~ TM-04-1 0-1 2-22-A-1 28: Specimen from the same general locality as the "-22-A-121" sample, above. Consists ofi magnetite-chalcopyrite- +/-?. TM-04-10-1 2-22-A-1 29: Specimen from.. the same general locality as the "-22-A-121" sampie,. above. Consists of magnetite-pyroxene --> phiogopite/tremolite-actinolite/? -chalcopyrite-bornite (trace amount}. Features chalcopyrite and calcite on planar/vein-like surfaces as wren. TM-04-1 0-1 2-22-A-1 30: .Specimen from the same general locality as the "-22-A-121" sample, above. Consists of magnetite-phiogopite-chalcopyrite- +/-?. Magnetite varies in crystalline/grain size. TM-04-1 0-1 2-22-A-1 31 Specimen from the same general locality as the "-22-A-121" sample, above. Consists of magnetite-forsterite/serpentinel +/-?. TM-04-1 0-1 2-22-A-1.32: Specimen from the. same generai loeafity as the "-22-A-121" sample, above. Consists of magnetite-bornite (trace amount)-phiogopite-calcite- +/-?. TM-04-1 0-1 2-22-A-1 33: Specimen from the same general locality as the "-22-A-121" sample, above. Consists of phiogopite-serpentine-magnetite- +/-?. T M-04- 1 0- 1 2-22-A- 1 34 Specimen from the same general locality as the "-22-A-121" sampie, above. Consists of magnetite-phiogopite-chalcopyrite-bornite- +/-?. TM-04-1 0-1 2-22-A-1 35: Specimen from the same general locality as the "-22-A-121" sample, above. Consists of magnetite-phiogopite-calcite. Apod/lens of crystalline calcite was noted occuring within magnetite crystals in one location in the specimen. TM-04-1 0-1 2-22-A-1 36: Specimen from the same general locality as the. "-22-A-121" sample, above. Consists of magnetite-phiogopite-calcite- +/-?. TM-04-1 0-1 2-22-A-1 37: Specimen from the Sdrne general iU(:alily aS file "-L2-A- 121" Sample, above. Con51StS of pyroxene(?)-phiogopite-magnetite(?)-chalcopyrite-bornite-malachite-azurite-calcite- +/-?. Complex sample. TM-04-i 0-1 2-22-A-1 38: Specimen from the same general locality as the "-22-A-121" sample, above. Consists of magnetite-phiogopite-calcite(?)- +/-?. TM-04-1 0-1 2-22-A-1 39: Specimen from the same general locality as the "-22-A-121" sample, above. Consists ofi pyroxene(?)-magnetite-forsterite{?}/serpentine(?)/calcite(?)- +/-?. 38-A GMC DATA REPORT 3 4, 4 Page los/11~ TM-04-1 0-1 2-22-B-1 04: A VERY NICE SPECIMEN. "skarn"; "intrusive"/"front", "zoned.. Collected in the vicinity of the skarn "apophysis°/"lens° at the north edge of the Arctic Chief (west) pit entrance. A "cognate float" sample, from below °map #3" (ie. TM-04-6-9-3) locality. Specimen is approximately 16 cm in its maximuml"longestn dimension. Displaying six apparently recognizable individual/discrete "zones", as follows: Zone 1. 3.7 cm in apparent width, as measured on the specimen surface selected for study. Periclase (bruCite) marble, with minor/trace spinet(?), +/-?. Light grey, banded". Zone 2. About 2.0 mm "wide". Clear-grey. Coarse crystals of quartz(??), calcite(?), in a .lens-like "border" region between zones 1 and 3. Zone 3. On the order of 4.0 mm "wide". Dark grey-greenish-yellowish. Banded. Calcite(?), forsterite{?), pyroxene{?), +/-?, Zone 4. About 5.0 mm "widen. Ayellowish-greenish zone. Forsterite(?), +/_?; calcite(?}. Zone 5. On the order of 13.0 mm "wide". Dark greyish. Pyroxene(?}, phlogopite(?), other "micaceous" mineral{s)(?), +/-?. Zone 6. Approximately 16.0 mm in apparent width, as measured across this "tongue-like" feature which is surrounded by immediately-adjacent zone 5 material. Pinkish in color. Likely(?) altered igneous material -- ie. zoisite(?)/clinozoisite(?)/epidote(?)/+/-??; or garnet(??), calcite(.??), +/-??. This "illustrative" specimen is moderately-strongly fractured, with most of the evident fractures oriented more or less sub-perpendicularly to the "borders/margin" of the "apophysis/intrusive(?)/replacement zone ("6"}, wherein the "skarn" material presently .occurs. This .latter perhaps/likely associated with a "long-lived° (or otherwise) fracture, oriented along the (apparently, in this view} long axis direction of the present mass of "skarnn and related zones surrounding the garnet, +/-, "core". (?). This is the specimen described by S M Aleksandrov in his paper "Gold Behavior during Endogenic and Supergene Alteration of Sulfides in Maanesian Skarns~ BY S. M ALEKSANDROV, PUBLISHED IN GEOCHEMISTRY INTERNATIONAL. 2007, VOLUME 45 No 2, R-Q 152-169 The following is taken from remarks of 7CM, in his "reviews of this paper, in the present report (above, pp. 7-9, which cf.): ......... Among others, one important point in particular seems worthy of special note here in this commentary. On page 154, Aleksandrov observes: "The magnesian skarns of the Arctic Chief deposit occur not only at contacts with the [main] intrusion but also around injections of diorite melts into dolomites (Fig. 2). The rocks preserve their zoning and inclusions of Mg- ludwigite in the forsterite calciphylres but contain no magnetite or•e mineralization" [asst/v~iated directly YY ith the lattel, ~Illall GlJmillVi `In,el.llVll.)', ie.~. Illustrative of this, his Figure 2, on his page 156, offers a drawing of a rock specimen. This specimen happens to be the one designated `T M - 0 4 - 1 0 - 1 2 - 2 2 - B - 1 0 4" when it was collected in the field at the Arctic Chief on Octoberl2, 2004, at sampling locale "22-B". Described by TCM in his "triage" phase of analysis as a "VERY NICE SPECIMEN", among other comments. This specimen was subsequenty sent in its entirety to Aleksandrov. Studied, depicted and discussed, by him. Who also apparently found it a `very nice specimen'. Collected in the near vicinity of a larger skarn/apophysis/lens of tongue-like aspect, featuring zoned igneous and "skarn" materials within carbonate host rocks, with green, .~•,iue, +/-, "rusty"-tcopper-staining present in places along its margins. This larger featur~,;,is °a 39-A 6MC DATA REPORT 3 4 4 Page 109/117 rather "gaudy"fspectacular one; well-photographed, 2004 and later. As weN as, subsequently, in 2006, collected in detail as samples "TM-06-8-22-2-........". Cf. maps, descriptions, etc. by TGM in the "Data Supplement" of the present. report. Location is at the northern edgelmargin of the entrance cut of the Arctic Chief (west) pit, exposed up on the sidetwail of the cut. In the vicinity of the. corelcrest of a tight/overturned fold in the carbonate host rocks. Below map#3 (ie. TM-04-6-9-3 locality). (From selected. portions of earlier letters from SMA to TCM: "Ludwigite is in serpentine-bearing marble T M - [ 0 4 ] - 1 0 - 1 2 - 2 2 - B - 1 0 4, very little. May be in contact with marbles you can see kotoite Mg3(B03)2???......." "You can see rhythmically-banded textures, that inherit, and in magnetite ores. (The best you can see in T M- 0 4- Y 0- 1 2- 2 2- b- 1 0 4--- [the sequence] around diorites' injection in marbles:. exchanged ["altered"] diorite--clinozoisite rim-- pyroxene skarn--banded Ludwigite-bearing forsteritic calci~hyre--banded pericfase (brucite) marble.) According to its caption, Aleksandrov's Figure 2 illustrates "diorite injection in dolomite and zoning in magnesian skarns~...........` Recognized as such in the field, too. Collected with precisely this intent, this specimen is used as an example -- "in microcosm", as it were -- of the general relationships ("positions") typical of magnesian skarns, at various scales from hand specimen, as here, through "deposit scale". Per the "model° for the "geochemistry of skarn and ore formation in dolomites" as developed and set forth by Aieksandrov and -his associates over a period of many years. Providing further illustrative bonuses, as observed, and depicted, this informative specimen also features "rhythmically banded forsterite calciphyres", and "disseminated crystals of magnesioludwigite°. fn addition to the other compositional and textural features characteristic of magnesian skarns so nicely displayed in this one specimen.. Collectively, "Letting the rock speak for itselfry, as it were........ This Figure ,this. specimen, the evidence afforded, supplemented by Aieksandrov's comments, sufficiently informative to merit incorporation in the present report. A "Key" item. Thus his Figure 2 and caption are reproduced below, on page "Insert//SMA-156": 40-A GMC DATA REPORT 3 4 4 Page 110/117 ] $6 ALEKSANDROV ,l l ~1~ 11:5.1 1 1.11 I r Il l lrr /l . i ~/ //// ///' ~' - - _ _ - - 1~~*t+~~~r\rl\\i\~Ilil~\\\\~~I\\\~~;``~~lll~~~~~/irri ~h 1 11111 Ldl \ 111 1 \ ~ ~~ \\ ~ ..~'' 4 n ,I Ir"1j, }~~/111111111`Ui`I11~1\~1~\'~\'111;I~~;FoCa~l~~;\1~\~ 3% . ~aY., \\\ \\1\ l 11\\1`11 .~~11'';1111 1\ ~.`./ ~ _= 4j/rr \ ~.. ~ ~ ~~ . . \ \ .~. . ~..~ .~ .` ;~ ~'~~'/r/ j .,\ \1111 II ~'., . ... `.: ` 111`\ ` `~`` 1 1..` .~ .~ _a;,i.~~,'r , ,rir/lu ~\ r: ~ .~1 1111 `i.a ~ . ~ _ ~i ii/ .. \ 3 ' ,' ~ q1~ l , llln r /rr rr t % /it rt ~'~~t'~u<$= ~' of /i'1\' \\ 1 Il/I/ / r!/rrl l//l/ ~/ll'Ill 11\11* ~, III#'~ ~~~ ~~/fir%di \~`\~~~ ' 1 rr r r r / /lll 0 r~ / ~ 11 11 r 1 i \I 1 1 2 11\~ ` \ ~~ ~ ~ :'4 CIIT ~ ~ =_-_- \ li \. 111 \ _ ._ ~ ~ . .. Fig. 2. Diorite injection in dolomite and zoning in magnesian skates. Arctic Chief deposit (sample of T.C. Mowatt), (1) Diorite replaced by zoisite (Zo); (2) phlogopite-diopside skam (Ph); (3) diopside skarn (Di); (4) rhythmlically banded forsterite calciphyre (FoCa); (5) disseminated crystals of magnesioludwigite (Ld). Magnification 2.5x. ((INSERT/lSMA-156)j GMC DATA REPORT 3 4 4 Page 111/117 TM-04-10-i 2-22-B-i i4: Specimen from the northwestern part of area "22-B", at the northwest side of the Arctic Chief (west) pit entrance. This is below map locale #3. A "float" sample. Features. a "plug-like" zone/lens/tongue of "skarn" into/surrounded by carbonate "host/country" .rock. Presumably (?) fracture-related. "skarn" consists of apinkish-brownish garnet "care", rimmed with a °calcite+magnetite(?)+pyrite+garnet" zone, featuring relative concetration of magnetite(?) pyrite(?)- +/-?. The carbonate rock -- periclase (brucite) marble -- is white-light grey. It consists of the rock-forming assemblage of calcite and periclase (brucite), with minor-trace amounts of associated pyrite (euhedral, +/-), magnetite(?}/molkbdenite(???), +/- graphite(??). Specimen contains some fractures, best observed on weathered surfaces. TM-04-i 0-1 2-22-B-115: A "fbat" sample, .from locality "22-B", below locality "3" at the northwest side of the entrance to the Arctic Chief (west) pit. Features a "skarn" ptugllens/tongue into carbonate host rock. The larger of the. two broken pieces was sent to SMA, the smaller piece, containing the "snout" of the plug/lens, was. retained. The carbonate host rock is a white periclase (brucite) marble, with trace amounts of associated graphite(?)fmolybdenite(???~, pyrite, and spinet(?). The "skarn" material(s) is/are dark grey-blackish; pyroxene(?)-magnetite(?)- sulphides (pyrite?, +/-?), as well as a minor-trace amount of reddish-pinkish-brownish garnet. TM-04-1 0-1 2-22-B-1 1 6: A "float" .sample, from locality "22-B", below locality. "3" at the northwest side of the entrance to the Arctic Chief (west) pit. Specimen features serpentine, with aseam/vein of white {calcite?) and dark grey/black materials}. Pyroxene(?), serpentine, forsterite(?), epidote(?), calcite, magnetite(?)/other black opaque mineral(s)(?); trace of sulphides(??.). TM-04-1 0-1 2-22-B-1 1 7: A "float" sample, from locality "22-B", below locality "3" at the northwest side of the entrance to the Arctic Chief (west) pit. An "alterered/retrograded" pyroxene skarn material(?): pyroxene --> tremoliticl actinolitic apmphibole//talc(?)/+/-?. With some calcite(?) and sulphides ~p~rrite?1. TM-04-1 0-1 2-22-B-1 1 8: A "float" ~a~Tipie, iium IOCaitty "22-B", below Iv~aiity "3" at the northwest Side Uf the entrance to the Arctic Chief (west) pit. An "illustrative" specimen. Specimen is about 11.0 cm in its "longest" dimension. "Banded/zoned", as follows: Zone 1. 15 mm in apparent width, as measured on the face selected for study. Aplagioclase- pyroxene rock; a "dioritic", or "endoskarn" material(?). Zone 2. 4.3 cm "wide"..Pinkish garnet. Zone 3. 3.5 cm "wide". Pyroxene, moderately altered to tremolitic/actinolitic amphibole(?), +/-?. Zane 4. 1.5 cm "wide". Phlogopite. Zone 5. 1.5 cm "wide". Forsterite(?)/serpentine(?)/+f-?; spinet(?), maroon-red- brown "magnetitelhematite(?)", black opaques. 41 -A GMC DATA REPORT 3 4 4 Page 112/117 TM-04-1 0-1 2-22-B-1 1 9: A "float" sample, from locality "22-B", below locality "3~ at the northwestside of the entrance to the Arctic Chief {west) pit. Periclase (brucite) marble. With associated "black-smoky" spinet(?}/or some other more or less opaque. mineral{?), occurring as eu-subhedra (tetrahedra?!cubes?/+/-?). f"Borates"??], This.."spinelfopaques/?° material(s) comprises an appreciable (+I-30% ?) component of this specimen. TM-04-1 0-1 2-22-B-140: A "float" sample, ftom locality "22-B", below. IocaGty "3" at the northwest. side of .the entrance to the Arctic Chief {west) pit. Pyroxene --> tremolitic/actinolitic amphibole - serpentine(?} - forsterite(?) - spinet(?) -trace garnet(?) -trace magnetite{?} -trace plagioclase(?). Pyroxene and plagioclase sub-euhedral. "Exo-/endo-skarn"(?) - ie. "plagioclase-pyroxene rock"(?}. Or....... ? Note a concentration of chalcopyrite at one end of the specimen intergrown with Qyroxene (within pyroxene c~stals too) and disseminated among pyroxene and plagioclase Specimen appears to perhaps be "silicified° (?1. TM-04-1 0-1 2-22-B-141 A "float" sample, from locality "22-B", below locality "3" at the northwest side of the entrance to the Arctic Chief (west} pit. Copper mineralization at one end of the specimen. Pyroxene(?}/magnetite- phlogopite-chalcopyrite-bornite(tracel-malachite-azurite- cak;ite. TM-04-1 0-1 2-22-8-142: A "fiioat" sample, from locality "22-B", below locality "3" at the northwest side of the entrance. to the Arctic Chief (west} pit. M agnetite-serpentine?/forsterite?/+/-?. TM-04-10-12-23-105: A fractured, banded/layered/sheeted specimen. Weathered, but with some interesting structures and mineral textures/intergrowths. Calcite-magnetite-chalcopyrite-malachite-/hematite(?)- +/-?. TM-04-10-12-23-106: Massive crystalline magnetite, with subordinate ("yellow-green") crystalline forsterite(?)-serpentine(?)- +/-?. Yellow-green, +f- some white, crystals are inter gr oirvn~ amor•~g ii,~aynet a yr yatais, aS weii a$ aivi g fractiii es ii ~ specimer'~. TM-04-10-12-23-108: A "granitic" rock. Float/excavated/"cast" material from the southern end of the Arctic Chief (east pit. A few fractures; three sets/directions/attitudes noted. Some apparent(?} inclusions(?), dark as well as light. (Or, perhaps, "phenocrysts"?]. Plagioclase-pyroxene/hornblende(?)-some calcite(?)-some "rosy quartz(?)-trace chalcopyrite; magnetite(?). A few fractures -- some with chalc~rite, +/-. Others with' dark green crystalline material, +/-. Fractures bordered by "leuco"/light-colored zones ("bleached"?) -mostly plagioclase and/or?. 42-A GMC DATA REPORT 3 4 4 Page 113/117 "Intrusive"......... or "endoskarn"........ (?). Appears. "dioritic", on cursory. examination with the stereo-microscope (?). TM-04-10-12-23-109: Specimen represents float/excavated/"cast" material from the southern end of the Arctic Chief east pit. A "graniticH ("dioritic") rock. Texture igneous, or recr•ystaliized/ metamorphic, or "contaminated" more. leucocratic intrusive magma(?). Intrusive, or endoskarn, or...... (?). Fractured, with "bleached" border zones, greenish vein-filling epidote. Plagioclase{twinned)-pyroxene/hornblende(?)-quartz{???)-calcite(??), magnetite (??). Trace chalco~yrite. A "plagioclase-pyroxene" rock, apparently; of .one sort or another. Apparent(?) igneous .crystallization textures, with plagioclase and pyroxene(?) eu- subhedra intergrown. Some retrograde(?) chloritelserpentine(?)-- (after pyroxene?). Some plagioclase crystals feature "cores" of greenish crystalline (epidote?/+/-?) material(s) (altered. anorthite-rich cores, or ??). TM-04-1 0-1 2-23-1.1 0: Specimen represents float/excavated/"cast" material from the southern end of the Arctic Chief (east pit. "Dioritic" rock. Plagioclase (sub-euhedra, twinned), pyroxene (sub-euhedra), epidote (especially as alteration product in central/core locations in plagioclase crystals). Some "rosyH pinkish quartz(?) here and .there. Trace pyrite(?). with a few crystals of apparent cube-pyritohedron aspect. adjacent to plagioclase and pyroxene as individual grains (some noticeably striated) A few fractures cross the specimen, with associated dark green-black (chlorite?, +/-?) material(s) as "fillings". Some interesting textures, with apparent igneous character of intergrown plagioclase and pyroxene rock-forming minerals. TM-04-10-12-23-111: Specimen represents float/excavated/"cast° material from the southern end of the Arctic Chief (east pit. An altered "granitic" rock. Actually "dioritic", featuring. pyroxene (altering/ed to chlorite, +/-), and plagioclase (altering/ed to clinozoisite/zoisite/epidote, +/-). Trace moiybdenite(??), magnetite(?). A few fractures, with associated epidote, +f-. 43-A GMG DATA REPORT 3 4 4 Page 114/117 OTHER OBSERVATIONS ON SPECIFIC SPECIMENS (S. M. ALEKSANDROVI "First. commentaries for your samples: Common look - as also in Brooks Mountain .and Tin Creek [Seward Peninsula, Alaska] in .Arctic. Chief rocks. [Emphasis by TCM] ...... in TM-04-10-12-22-a-134 and -131 and -102 --- banded phlogopite-- magnetite ores, in -126 --- serpentine/forsterite rhythm in magnetite; in T M - 0 4 - 6 - 9 - 4 - 2 --- is forsterite--calcite rhythm, etc....). These textures have origin on progressive stage of metasomatic exchange of dolomites and reflected in ores-- see book [SMA, 1998], pages 77-87. It is non-equilibrium process." " In your collection is ~lendid periclase marbles, but in literature are not this information. In many samples in marbles and forsterite-calcite environment are a bit to big black crystals of LUDWIGITE {see TM-04-10-12-22-b-115; -23-110, -23-108, etc. See Brooks Mountain! This full~are not in literature about Whitehorse copper belt! [Underlining in above is original in letter from SMA; bold emphasis added by TCM.] About typical lime skarn (T M - 0 4 - 0 8 - 0 9 - 2) [of] pyroxene-garnet composition: What is its position with magnesian skarns? I believe that. it has postmagmatic origin from Si-bearing marbles. What, how much, are sulfides in this type skarns?? Or absent? In forsterite marble (T M - 0 4 - 6 - 9 - 5 - 1) is spinet. The part of pyroxenes is Al-bearing. In this situation is formed .late phlogopites in rocks and ores ............. About dykes and its composition. In last letter I note about leucocratic hornblende quartz monzonite dyke. It is possible that monzonite from massif will be more basicl If this so /well then/ you can think that monzonite magma of massif is result of assimilation. of host rocks and primary melt was more close to granitic composition and was superheated. Last dykes from deepest magmatic camera must be leucocratic. In book [SMA, 1998] (Fig. 13) is illustrated this, and similar with Arctic Chief locality. [Emphasis by TCM]. (tn text, epidote = clinozoisite). Plus, see green amphibole with plagioclase in quartz-monzonite dy ke_ T M- 0 d- 1 0 -1 2- 2 3- 1~ 8, 1 1 0:"~:th p3~'oxenes and quar<z." TM-05-5-25-1-Q: "Probably in this specimen is ludwigite in the marble .part near contact with forsterite- magnetite ore. .........." "Marble with ludwigite (??????) as black needles . ............" "l will be send you new [[microprobe]] analytical data. for sample #TM-05-5-25-1-Q (marble with Ldw?????? and + magnetite ore............ )" [An excerpt from a letter from SMA to TCM, May 11, 2006 states: "All black needles are pseudomorphoses magnetite after borates ............."] 44-A GIV~~ DATA REPORT 3 4 4 Page 115/117 "Other minerals in this specimen: fUlg-bearing. magnetite- (>90% FeO, and 1.5% MgO) Dolomite- (22% MgO, 30% CaO) Serpentine- (36% MgO, 3% FeO, 45% SiO2) Phlogopite, altered to ciinochiore- {with MgO, SiO2, and AI2O3) Talc- (MgO, SiO2) Are [also] Fe-Mn species dolomite/ankerite." "Near monzonite plag and prx -- transformed into zaisite and calcite; and prx -- into Mg phlogopite. All periclase in marbles fully transformed to brucite, with calcite; its form is pseudomorphic after periclase. In these rocks are a few grains of forsterite and clinohumite. In magnetite ores forsterite is transformed into serpentine near calciphyres, or into other silicates --- into Mg-phlogopites {after diopside). Mg-pyroxene is in T M - 0 4 - 1 0 - 1.2 - 2 2- A~ 1 3 7 and actinolite........ 2 2- B- 1 1 7, amphiboles........ 2 2- A- 1 0 1. Green amphibole with plagioclase in quartz-monzonite dyke- TM-----23-108, 110 with pyroxenes." "TM-04-8-9-2-Z: Vesuvianite (idocrase)-pyroxenic typical barren skarn. TM-04-1 0-1 2-22-A-1 01: Actinolite in magnetite ore. TM-04-1 0-1 2-22-A-1 13: Brucite-periclase_ marble, with forsterite and clinohumite. Microprobe analysis: P-68-2. Brucite and periclase, some dolomite. TM-04-1 0-1 2-22-A-1 21: Phlogopite in magnetite ore. TM-04-1 0-1 2-22-A-1 26: Rhythmically-banded serpentine-magnetite ore. TM-04-1 0-1 2-22-A-1 30: Magnetite ore with phlogopite. TM-04-1 0-1 2-22-A-1 31: Magnetite ore with phlogopite; magnetite is prismatic. TM-04-1 0-1 2-22-A-1 32: Magnetite ore with phlogopite; magnetite is prismatic. TM-04-1 0-1 2-22-A-13.3: Phlogopite-magnetite ore. TM-04-1 0-1 2-22-A-1 34: Magnetite ore with phlogopite; magnetite is prismatic. 45-A Gt~~i u~iTA REPORT 3 4 4 Page 116/117 TM-04-1 0-1 2-22-A-1 35: Magnetite ore with phlogopite; magnetite is prismatic. TM-04-1 0-1 2-22-A-1 37: Diopsidic skarn .with prismatic magnetite. TM-04-10-1 2-22-8-1.04: Forsterite-bearing brucite (after periclase) marble, with calcite, serpentine and phlogopite. .Microprobe analysis: P-67-2. Forsterite, serpentine,, brucite, phlogopite. TM-04-1 0-1 2-22-B-1 14: Rhythmically-banded serpentine-magnetite ore. Serpentine after forsterite. TM-04-1 0-1 2-22-B-1 1 7: Actinolite after diopside, in magnetite ore. TM-04-1 0-1 2-22-B-.1 1 9: Brucite-periclase .marble. Microprobe analysis: P-68-1. Brucite .with relicts of periclase, and dolomite +spinel + hydrotalcite (after spinel) and magnesite. TM-04-10-1 2-22-B-141: .Magnetite ore with serpentine. TM-04-10-12-23-106: Rhythmically-banded serpentine-magnetite ore. Serpentine after forsterite. TM-04-10-12-23-108: Plagioclase rock with amphibole (dike???). TM-04-10-12-23-109: Clinohumite calciphyre .with magnetite. TM-04-i 0-12-23-110: Plagioclase rock with hornblende and pyroxene (dike?)_ TM-04-10-12-23-111: Skarned zone on contact. with dike. Content anorthite, pyroxenes (fassaites) and garnet.' The typical in contact magnesian skarn plagioclase-p;aoxene C~mpositin^ a.^.d secondary ["ply; transformed in [into] salite-garnet bearing associations. Microprobe analysis: P-67-1. Salite, plagioclase (anorthite), garnet (grossularite 70%, andradite 30%), pyroxene.. TM-04-1 0-1 2-23-B-1 1 5: Brucite (after periclase) marble with forsterite. TM-05-10-13: Rhythmic-banded marble with sulphides." 46-A ~f`VI~ IJH1H REPORT 3 4 4 Page l`l7/~1T
