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Home My WebLink AboutGMC Data Report No. 038Potassium-Argon age determinations for the General Petroleum Corp. General Petroleum Corp. Gulf Oil Corp. Great Basins No. 1, Great Basins No. 2, and Port Heiden No. I wells. 18 April 1975 Total of 7 pages in report Geologic Materials Center Data Report 38 . ( SHELL OIL COMPANY P.O. BOX 527 HOUSTON, TEXAS 77001 April 8, 1975 Mr. Thomas R. Marshall, Jr. Chief Petroleum Geologist Alaska Dept. of Natural Resources Division of Oil and Gas 3001 Porcupine Drive Anchorage, Alaska 99501 Dear Mr. Marshall: With your permission, Mr. Jerry Sager of our Anchorage office selected a core sample for radiometric age dating. The sample data are as follows: Gulf 0il Port Heiden No. 1, Section 20 T37S R59W, Seward B. & M., Bristol Bay Basin, Alaska Core depth: 15006-07 feet The attached report of analytical work from Geochron Laboratories provides the pertinent details. Geochron also stated: "From sample AKA-S-201, we .separated a concentrate of very fine grained, pale green hornBlende for analysis...The amount of sample was not large, amd this analysisw~as also difficult. Again, we believe that the reported age is the best that can be determined from the rock sample submitted." Hornblende provices a much better radiometric age date than the whole rock method, and we are fortunate that they were able to isolate enough hornblende to make the analysis. The measured age, 37.7 ± 2.0 m. y. falls near the Oligocene- Eocene boundary. We appreciate your cooperation in providing us with the core material required to make the analysis. Yours very truly, GMC Data Report 38 Page 1/7 · o m, · ! FIDENZA[ ' CON " ,,,,, -,-,., ,, '". ,",,', '"' "-'"" ,, ', -. Oev~lolmlent Contpa~y, Its " freel~ to Gulf employees k~t Ized, to outsiders. ,,,oM N.D. Coggeshall ' ^v Harmarville ',', ~lr. B. W. Miller ^v Bakersfield Atttl: J. P. Grates ' · ,,,JECT A(;i': ])]':TERMINATIONS: CUTTING AND CORE A-- 72-0042~2~(-'/- ~- O^VE August 28, 1972 REFERENCE 4201DC44 Results of potassium-argon age determinations on cuttings and a core sample from the subject well submitted under cover of letters-W..J. Cage, Jr., to T. J. Weismann, August 16, 1972, and D. A. Davis to H. A. Skillibeer, August 9, 1972, are reported confirming phone conversations ~;ich T. J. Weismann during the week of August 21, 1972~ The samples are: Sample #1 Cuttings 10,980-10,990' Sample #2 Cuttings 10,990-11,000' Above samples described as porphyritic igneous rock which.is believed to be extrusive in nature (N. D. Coggeshall/D. A. Davis to I;. W. Miller, "Petrology and PalynOlogy of Cutting Samples, Port Heiden [h~it No. 1, Alaska", August 4, 1972). ~;a.,iple #3 Core 11,832-11,833' 't.'ertinent data: Spl, #1 Spl. #2 SPl. #3 I'o l:assium Content ~;rAr40/GrSpl , ',", l~adiogenic Argo~n A ~.l, 0 /K40 ' t.:a;Lculated Age (m.y.) 2.63 -9 2.64 _ 2.70 8.00xl0 7.97x10-M 7.79x10-9 ' 35% 40%-3' 50% 2.52x10-3 2.50x10 · 2.39x10-3 43+4 42+4 42+4 'l'l~e three samples ~ated are remarkably similar in potassiu~ content, quantity of radiogenic gas, and determined age. The radiogenic character of the gas is typical of that found in 5~ 'i '! 197,.?. N. ~. Cof~g~h~ll -",:':' ..~" " ~u~ n.+. Do~+ qn Page 2/7 .CO I[:igENTIAL ' C ~ This document is the property of the Gulf Research & ' GavMop::mnt Compaay. its contents should be revealed ':,'no:y to Gulf employees but nots unless specially author- : i.: .d. to outsidot8. N.D. Coggeshall AY Harmarville vo Mr. B. W. Miller AT Bakersfield SUBJECT Age Determination, Igneous Rock, 13,972', Port Heiden Unit No. 1, Alaska Re Lette~ 9'/~i/7:2, DADavis-HAShillibeer A-72-0045-11-( /, .) .E~E.E.CE 4201DC44 The subject sample originally submitted by Mr. Gates to HTSC has been forwarded to Harmarvil!e and dated by the K-Ar method. · ,~ The material is an altered (chloritized) very fine-grained igneous rock recovered in the junk basket from 13.972' in the well. Altered material of this type will yield an experimentally determined age lower than the true age. The calculated "age" for this material is 36 million years. Because of the extent of alteration, this may be considered in good agreement with the 42 million year age determined on samples taken higher in the well. Pertinent. data are given below: Potassium Content GrAr40/Gr Spl % Radiozenic Argon Ar40/K40 Calculated Age 2 05% -9 = 5.32x10 = 22 -3 = 2.15x10 36 + 8 million years As expected, the potassium content of this sampl~ is lower than · that of the other volcanics in the well, probably through alteration loss. Likewise, the amount and quality of the extracted argon is low, reflecting alteration and atmospheric contamination. The determination was performed by R. T. Rupert. Above information was reported to your office on September 14, 1972, in a telecon between B. W. Miller and T. J. Weismann. If we can be of further help, please advise. cc: M. J. Hill H. J. Funkhouser SE? Z Gulf ()il Co. Anchorage- RECEIVED · - EP 25 TLL PSD /~ DIVISION OF OIL A~, CH. OR," 0": CMO na~-~ I~nnrt 38 Page 3/7 KRUEGER ENTERPRISES, INC. GEOCHRON LABORATORIES DIVISION 24 BLACKSTONE STREET · CAMBRIDC, E, MA. 02139 . (617)-816-369! POTASSIUM-ARGON AGE DETERMINATION' REPORT OF ANALYTICAL WORK Our Sample No. A- 2980 Date Received: 30 December 1974 Your Reference: AKA-S-201 Date Reported: 22 January 1975 Submitted by: Castano Shell Development 3737 Bellaire Blvd. Houston ,TX 77001 AKA-S-201 Gulf Oil Corp. Port Heiden Unit No. 1, Sec. 20 T37S P.59W, Seward B.&M., Bristol Bay Basin 15,006-07 ' Sample Description & Locality: Fiz~e graJme~ g~:a~oAierjte(?), Ar, A-S-201'. Material.Analyzed: Hornblende concentrate, -80 mesh. Estimated comPOSition: hornblende, 80~; Ch!oritized biotite, 15 ~; Others, 5%. Ar4°*/K4° = .002230 AGE= 37.7 + 2.0 Pale green Argon Analy~s: Ar4°*, ppm. .002546 .002044 Potassium Analyses: %K .840 .847 Ar 40*/Total Ar 40 .194 .156 Ave. %K .843 Ave. Ar 4o*, ppm. .002295 K4o ,,.o29 Constants Used: ;¥ = 4.72x 10-'°/year ke: 0.585 x 10-~ o/year K "°/K = 1.22 x 10'4 g./g. Note: Ar 40- refers to radiogenic Ar 40 M.Y. refers to millions of years. AGE -. ;ke+ ~kj3 . in ~_Xi3 + Xe L k.e Page 4/7 9 September 1969 Pan t. .... ~-~.~ PetroZeu:.: Security Life P,!ds~ Denvers Colorado 80202 Dear Mr. Stansberry: ,We have now ccr:.ple%ed the potass' '-'~-'''''''~ ase ~ ....... ' ~' - describer in'your letter of ].5 July ~....,. ...... tionc on ti:re.": of these sez~ples and you will find thc. sa writ'ben repor%s enclosed. ... , , ~,.~ at a ceoon of ii '-':'"" save an age of 120 moy, A se3:..':ple fro:.: ~.~obil Great Basins ~:~' ' ~ c,~ - ~ ~. ~ ~ - ~ ~ o ~.' .~ This is an ~' - · ' ' ~2 %:ell gave an adherent ' ~ C-~ ~2, ...c ~i - ale of ~..~5',. We naa ant~ ....... this a:~aly:.' ~, but we were u.ntf~le to ....... -- = .... =-'- to v, roviie you with sona to ~o ~'~.,~ and .... -,,.-., _ ....? .... .. ., ..... 96.3 z'a~y is s!~.gn~!y yoking and that t=e ...... ~ ........="'"~" ~-e~,' to be aoout 120 ,m.y. old as a result of a small amount of arson loss from tlne feldspars. - '-, ....."these _uo,,l%,, will be suez'~, vo you an,~ ~na~ you ~.;inq ~¢~ in touch with - ' ~ · -~ ncr :%e if you ka?c ou~ invoice .ior ~hege ane~yses an~ - nope ',re '"~ have tke gleasure of servzns you ~Jz~ Pan GEOCHROi.~ L.630k~TORIES ~ 'I~';Co / · Harold W. Kru.::ger Technica~ DJ'' Fu~ uor H:..'?.'./p7 encs o GhMC Data Report 38 Page 5/7 , , ~/..; L ;:' '::~' ff jr Telephon~ TRo',vbridge 6-359! REPOHT OF ANALYTICAL WORK POTASSIUM-ARGO;',: AGE DETERMINATION Our Sample No. B -132lt Your Reference· Submitted by' Mobil Great Basins #!, 'O. iF. Stansberry P~u ~haericm~. Pet. Coz'p. L~ze Bldg. Security ' ~ Denver, Colors. do 80202 Date Received: 28 July ]-969 Date Reported' 29 t:u~x~st..o. 1969 Sample Description & Locality- Altered grsnite, ~obil Great Basin ~'le!l~ 11~0!;0-11,0~! '. concen,rs.t~, Material Analyzed' Mica ~ ~ -.80/-:-200 mesh. Estir~ated to be 30 to 40~ biotite and muscovite, 30~ chlorite, remzinder a variety of hes;,~ minere,!So (Too ~mall for further purification). Ar4°~:/K4° = 0.00~27 AGE=3-20 (!6) x 106 yearso £~_r gb n Analys-os:' Ar4O* , ppm. · - · o,o0915 0.00711~ % K '0,923 0.9~ · Const~n,~s Os3d' --. 4.72x 10-~°/year = 0.585 >: i0-~°/year. 4 o/K = 1.22 x 10-4 g./g. GMC Data Report 38 A'r 40*/Total Ar 40 '0,503 0o M~5 Ave. %K o.917 AGE - in [?%0 + le L Ave. Ar 40 * · ppm. 0.00811; I( 4o., PPm Ar 4o* Kg0 , ?-~ ~. ~, ,, r-~ ~,,a_' :r'~-r~, ~- .~ ~ ~,..:-'-~'..-: ~ Page 6/7 REPORT OF At.'ALVTICAL ?OTASSIU:.i-A~iGO,~; AGE DF-TEF:.'.IIt-:ATIO¢~ Our Samp~e No. R -1325 Date Received: 28 July "--'969 Your Reference: Submitted by: Gen. Pet. Orec:b ~,,~'ins, i..'o, ~_, oo~o-ou-°°o" -~.-~a-,~.,~ Ee:,-'ortsd: .29 Augus% 19~9 · O. ~F. St~msber:-y Pe~ A.'.'cerican ~-" ~ c ~, Corp. Security Li£c Bldg, Denver= Colorado 80202 Sample. Description & Locality' S*,--,~! chip of ...... ~.~O- .~ u ~. Material Analyzed: l'?no].e roe'..: ( S~.~_ proved ~ ~ '*' -~ ~ ' ~..,ac~qu~,~e for separation of ~phibole concentrate. ) Ar 4o,..:/1( 40 = 0.00578 AGE =a.3 (~=5.5) x '106 years° A__[rgbn Analyses' Ar4 o-~- , ppm. ·0.00590 0.0051:4 el 0.781 Con2 Lqnts ;.]~3d' ,!;1 -'" 4.72:< I0-~.°/year ke = 0.5-35 x ~0-~ o/yesr. K 4o/K = ~.22 x i0-4 9-/2- ~ .o~. ~C,.c. ,%i'40':' .r... tO_ . 40 Data Repo~t 38 .. Al4°*/Total Ar 4o '0.5l;8 '0.495 0.804 AGE = Ave. Ar 4 o * :0.00567 K4o · ppm O.yo! i - in [XO + '~e Ar 4o* "· +'-.fl>' -L Ne x + 1 · K ~o