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HomeMy WebLinkAboutGMC Data Report No. 048· March 12, 1971
PALYNOLOGY OF THE SUSIE UNIT #1 WELL: NORTH SLOPE~ ALASKA MARATHON OIL COMPANY
ANCHORAOI~, A~
G. K. Guennel MAR 2~ 197!
Thirty-four samples of well cuttings were examined microscopically.
Standard maceration procedure was employed. This included HF and HC1
treatment, followed by oxidation with Schulze ' s reagent and neutr~aliz~tion. ~.-
with KOH. Floatation with ZnBr was alwo employed and staining was
-_:/ ~,.~-- < '.~ ~
accomplished with safranin ¥.
~.',~Vi~!~N C',~ ~'~;~....,, Ah~D GAS
Palynomorphs are fairly abundant and preservation is reasonably good
down to s~mple 9750-60. Below this point carbonization seems to have taken
its toll. Palynomorphs are rare and preservation is poor in the lower
samples, making identification difficult. Those well preserved spores that
are present in the lower part of the well are obviously uphole contaminants.
,.
The possibility that these rocks may-simply be devoid of palynomorphs
and that the carbonized fragments are allochthonous (reworked from older
sediments) has been considered but ruled out. Some of the carbonized
palynomorphs are recognizable as Mesozoic dinoflagellates and thus are
thought to be indigenous to the sediment. There is, however, evidence of
recycling of this Mesozoic carbonized debris throughout the upper portion
of the well. Depth of burial is thought to account for the carbonization.
The depositional environment is thought to have been marine from
4250 feet down to T.D., with possibly a non-marine interval between samples
6210-20 and 6800-10. The upper section, down to sample 3800-10, is thought
to be non-marine.
The well is thought to bottom in Jurassic rocks. The boundary between
,
the Lower and Upper Cretaceous is postulated between 7250 and 7500 feet and
the Cretaceous-Tertiary boundary between 1750 and 2300 feet.
-2-
AGE DETERMINATIONS
Figure 1 shows the ages, and thus a gross zonation, determined by
this rather cursory palynological investigation. Age determinations are
.extremely difficult to make for the samples of the lower part of the well.
Land-derived pollen and/or spores are lacking or are rare in these samples
·
and preservation is poor due to carbonization of the organic matter.
Figure 9, plate 2, illustrates this kind of preservation,
No evidence of Paleozoic sediments was encountered in this well.
Some dinoflagellate cysts, which are presumed to be indigenous to the
·
· samples and which resemble taxa previously encountered in Mesozoic sedi-
ments, date the lower portion of this well as Jurassic-Cretaceous.
Sample 120-50 -- This sample is practically barren. Quercus, Pinus, Osmunda,
Sphagn .u~., and Smilax are the only plant genera represented. This hints
at a b'oggy environment and probably Pleistocene or Holocene age. A
non-marine environment is postulated, since there are no marine organs
present. Fungus spores, however, are present. One carbonized dino-
flagellate is thought to be associated with carbonized wood fragments
and thus reworked from older sediment.
Sample..500-10 -- Spores are abundant and well preserved. There is no evidence
of marine organs. The palynomorph assemblage is dominated by Quer.c.us,
pteridophytes*, .a~d Taxodium. The percentage relationships are shown
graphically in figure 2. The abundance of Taxodium (12%) and the
presence of monosulcate grains (probably palm and Liriodendron) and
Sequoia (figure l, plate l) indicate a very mild warm-temperate climate
and point to an Early Tertiary age, probably Eocene.
.._
* Sphagnum, a bryophyte,, is arbitrarily included ............ .~--.-~...
Sample 1000-10 -- Spores are abundant and preservation is good. The assemblage
of this sample differs somewhat from that of sample 500-10 (see figure 2).
However, the lower Quercus. count may not be significant, since it may
simply be' attributable to a moister environment. An increase from 19%
(sample 500-10) to 31% in "exotics," on the-other hand, may. be signifi-
cant. By "exotics" I meau warm-temperate angiosperms, such as Myrica,
.Nyssa, ~, Ul.mus, Fagus, and Juglans, which are grouped under the
labeI WTA in figure 2, plus Taxodium~ Sequoia, monosulcates, and
Podocarpus. The environment of deposition is thought to be non-marine
and 'the age Eocene.
Sample 1500-10 -- Spores are abundant and preservation is good. The "exotics"
-
comprise 41% of the total spore count and thus the climate is presumed
to have been warmer than that of sample 1000-10. The appearance of
Gleichenia and .Rugutriletes, two prominent constituents, of Late Cretaceous
spore assemblages, may also be significant~ Podocarpus maximus is present
(figure 3, plate l) and this species is considered to be characteristic
of the Fort Union (Stanley, 1965). The environment of deposition is
non-marine and the age is thought to be Paleocene.
S.ample 1750-60 -- Spores are abundant and well preserved. The assemblage resemble~
that of sample 1500-10. The percentage of "exotics" has increased to 49.
Sequoiapollenites paleocenicus (figure 2, plate l) is present and it has
been found in the Paskapoo Formation of Alberta and the Fort Union of
South Dakota (Snead, 1969, and Stanley, 1965, respectively). Sphagnum
regium (figure 4, plate 1), reported from the Paleocene of'Siberia and
the Fort Union of South Dakota (Stanley, 1965), and Podocarpus maximus
are also present, indicating a Paleocene age for this sample. The
environment is thought to be non-marine.
Sample 2300-10 -- Spores are abundant and well preserved. The assemblage is char-
acterized by typical Late Cretaceous genera, such as Aquilapollenites,
Gleicheni..a, and Proteacidites (see figure. 2). AQuilapollenites rectus,
A. dentatus, and A. fusiformis were described from Upper Cretaceous rocks
of Alaska (B. Tschudy, 1969). _Cycadopites giganteu.s and Wodehouseia
spinata (figures 5-7, plate l) were described from the Upper Cretaceous
of South Dakota (Stanley, 1960). Wodehouseia .spinata has become a Late
Cretaceous marker. The presence of these species leads me to postulate
a Maestrichtian age for this sample. There is no evidence of marine
organisms.
Sample. 2750-60 -~ This sample contains well preserved spores in abundance.
Aquilapollenites is conspicuous due to its abundance and by virtue of
being represented by a new species (figures 8 and 9, plate 1). This
species is large and spinose and to my knowledge has not been reported
in the literature. Also present is A_. senonicUs (figure 16, plate 1),
which is limited to the Maestrichtian and Campanian (B. Tschudy, 1969),
and Wodehouseia spinata. There is no evidence of marine organisms. A
Maestrichtian age is postulated for this sample.
_S..amples 3250-60 and 3800-10 -- Spores are rather sparse in these two samples.
_Polypodiidites senonicus is present and thus the samples should be no
older than Santonian (Ross, 1949). A Campanian age thus is attached to
this interval. There is, however, a suite of Maestrichtian spores
present, including species of Aquilapol.l.enites, Momipites, Lycopodium-
sporites, and 0smundacidites. If these spores are indigenous, that is,
not uphole contaminants, then this interval could be Maestrichtian
rather than Campanian. There is no evidence of marine organisms.
.Samples 4250-.603_ 4750-.60:' 5250-60 -- Spores are fairly abundant in these samples.
Cingulatispor±~es circularis and gnemia striosporites are present and
,.
-5-
they are restricted to the middle Senonian (Weyland & Krieger, 1953, and
Rouse et al, 1971, respectively). The dinoflagellates Deflandrea rec-
tangularis (figure 1, plate 2) and D. belfastensis have also been reported
from middle Senonian rocks (Eisenack & K_lament, 1964). A middle Senonian
age thus is pretty well established for this interval and, since the samples
above appear to be Campanian in age, this interVal is thought to be
Santonian. Some uphole contamination is evident, by the presence of ~-
pollenite.s, Momipites, Taxodium, Wodehouseia, and Betula pollen. The lower
Upper Cretaceous, that is, the Cenomanian, Turonian, Coniacian, and San-
tonian, is a sequence with which I am not too familiar. A suite of spores,
:.
strangers to me but assignable to such genera as Rugutriletes (figure 11,
. -
plate 1), Leptolepidites (figure 12, plate 1), 0smun. dacidit, es, P_ilosporites,
Sphagnumspo.r..ites, and Lycopdiumsporite.s, is present in these samples and
this suite thus may well fit into this gap in my knowledge. A strange
dinoflagellate, assignable to ~Gymnodinium '(figure 2, plate 2), is also
present. The samples of this interval contain well preserved dinoflagellates
and thus are marine.
.S.smple 5750-60--This sample is essentially barren. Besides some uphole contami-
nants (C~as.tanea, Chenopodium), there is, however, a diagnostic hystricho-
sphere present, Hystrichosphaeridium readei (figure 5, plate 2). The sample
thus is probably marine and no younger than Cenomanian (SarJeant, 1967).
Sample 6210-20 -- This sample contains Verumonoletes morulus and Dacrydium fluens,
species that have been reported from the Cenomanian (Pierce, 1961). There
is no evidence of marine organisms. Uphole contamination accounts for the
presence of Momipites, ~Aquilapollenites, 'Taxodium, Engelhard..tia, Castanoa,
and Tilia. The age is thought to be Cenomanian.
Setup.les. 6600-10~ 6700-10~_ and_ 6800-10 -- Palynomorphs are sparse in this interval
and no age-diagn6stic fossils were found. No marine organisms were
encountered, except one hystrich and it is probably recycled from older
rocks along with some specimens of Cycadopite~s and Anemia that are Aptian
and older. There is also evidence of uphole contamination. A u_q~-
pollenites, .Sequoia, Taxodium, and Myrica pollen is thought to come' from
younger rocks.
Sample 7250-60 -- This sample contains the dinoflagellate Diconodinium arcticum
and the fern spore Striatites striatus (figure 4, plate 2) and thus should
be Cenomanian in age (Manure & Cookson, 1964, and Pierce, 1961, respectively).
The sample is marine. Some uphole contaminants are present, including
Taxodium, Aquil. apollenit.es, and Ulmipollenites.
Sample 7500-10 --This sample contains some well preserved dinoflagellates and thus
the environment of deposition is marine. Cicatricosisporites aralica and
and Sphagnumsporites .ant.i~quasporites (figure 5, plate 2) point to an Albian
age for this sample (Brenner, 1963). On the other hand, the presence of
·
Lycopodium fastigioides and Hemitelia mirabilis (figure 6, plate 2) indicate
a Cenomanian age (Couper, 1953, and Bolkhovitina, 1953, respectively). The
latter two species, along with specimens of .Aquilapo.llenit.e.s that are also
present, could be uphole contaminants.
~Samples 7750-60~ 8250-6.0..~ and 8760-70--These 'samples contain well preserved
dinoflagellates and thus the environment is thought to have been marine.
Dicodinium disp. ersum, D_. pelliferum, Microdinium ornatum, and Gonyaulax
apionis (figure 7, plate 2) are indicative of an Albian age (Sarjeant, 1967).
The spore species Monosulcites ..e. 10ngatus, Acanthotriletes levidensis,
Vitreisporites pallidus, Gleicheniidites senonicus, and .Podocarpidites
potomacensis substantiate this dating (Panella, 1966; Brenner, 1963; and
Balme, 1957). Pollen grains of Aquilapollenites, ~, Taxodium,
M~yr.ica, Carya, and ~agus are thought to be introduced from uphole.
.Sample 9250-60 -- This sample contains no diagnostic palynomorphs. Some well
preserved pollen grains, representing the genera Sequoia, .Gly~otostrobus,
Corylus, and Alnus, are indicative of uphole contamination. Some carbonized
dinoflagellates present are thought to be reworkmd from older rocks.
Sample 9750-60 -- There is no evidence of uphole cont_~_m~nation in this sample, but
some carbonized dinoflagellates are indicative of recycling of sediment.
A well preserved assemblage of palynomorphs is present and it is thought to
be indigenous. The dinoflagellates Scriniodinium campanula (figure 8,
plate 2), Gonyaulax orthoceras, and G_. jurassica make this sample no older
than Hauterivian and no younger than Aptian (Eisenack & Klement, 1964).
Long-ranging Cretaceous spores belonging to such genera as Classopollis,
Polypodiisporites, Sphagnum~sp, orites, and Gleicheniidites tend to support
this date. This sample is marine.
Sample 10:500.ri0 -- 0nly carbonized dinoflagellates are present in this sample.
There is no evidence of uphole contamination. The sample is marine. The
presences of the dinoflagellate Gonyaulax helicoidea, among others, makes
this sample no younger than Aptian (Sarjeant, 1967).
Sample 10,750-60 -- This sample contains only carbonized dinoflagellates. No
uphole contamins~nts are present. Two dinoflagellate species, Odontochitink
operculata and Gonyaulax orthoceras, make this sample no younger than
Albian and no' older than Hauterivian (Singh, 1964).
Samples 11~240-50) 11,760-_70_;_ and .1_2,600-10 -- This interval is devoid of diagnostic
palynomorphs. Among the carbonized dinoflagellates found is Gonyaulax
~urassica (figure 9, plate 2), a species that ranges into the Albian
(Singh, 1964) an~ thus is not of great help in dating this interval. The
interval is definitely marine. A diverse and well-preserved assemblage of
uphole cont_am~nants tends to obscure indigenous palynomorphsJ This
assemblage contains specimens of M.omipi.ties, Taxodium, ~yrica, Alnus,
Cor~rlu. s, Carya, ~, and .Juglans and thus must be derived from Tertiary
rocks way uphole.
Sample 12,800-1.0 -- This sample contains carbonized dino,flagellates. One dino
resembles Gymnodinium dabendorfense, a species reported from Valangian
rocks (Sarjeant, 1967), but I can't be sure of the' identification. The
sample is marine.
Samples 12,.960-70; 13,_050-60; and 13,160-70.--No diagnostic palynomorphs were
found in this interval so that dating was not possible. Carbonized dino-
flagellates are present, however, making the interval marine. Uphole
conts~nants are also present in this interval, among them are specimens
. _
of .Tsuga, Alnus_, Corylus, Momipites, and Taxodium.
.Sample 13~490-500 -- This ~ample contains carbonized dinoflagellates and hystricho-
spheres, indicating a marine environment of deposition. One dinoflagellate
cyst resembles Imbatodinium villosum, a species reported from Upper Jurassic
rocks (Evitt, 1969). Some well preserved spores' representing Betula,
Momipites.., Taxodiu~., and Gleichenia indicate that uphole contamination
occurred.
$ ·
- i1 -
BIBLIOGP~PHY
Anderson, Roger Y., 1960, Cretaceous-Tertiary palynoiogy, eastern side of the
San Juan Basin, New Mexico: Bur. Mines Min. Resources Memoir 6, 58 p.
Balme, B. E., 1957, Spores and pollen grains from the Mesozoic of western Australia:
Conm]onwealth Sci. Ind. Res. Organization, Tech. Communication 25, 48 p.
Baskerville, Charles Alexander, 1965, A micropaleontological study of Cretaceous
sediments on Staten Island: New York, U. Microfilms, Ann Arbor, 65 p.
Boikhovitina, N. A., 1953, Spores and pollen characteristic of Cretaceous deposits
of central regions of the U.S.S.R.: Trans. Inst. Geol. Sci. A6ad. Sci.
U.S.S.R., Rel. 145, Geol. Set. no. 61, 184 pp; in vol. 8 and Translations
vol. 2 of Catalog of Fossil Spores and Pollen, Pennsylvania State University.
Brenner, Gilbert J., 1963, The spores and pollen of the Potomac Group of Maryland:
Maryland Dept. Geology, Mines, Water Resources Bull. 27, 215 p.
Couper, R. A., 1953, Upper Mesozoic and Cainozoic spores and pollen grains: New Zealand Geol. Survey, Paleontol. Bull. 22, ?7 p.
_ _
De Jersey, N. J., 1970, Triassic mio~pores from the Blackstone Formation Aberdare
Conglomerate and Raceview Formation: Geol. Survey Queensland, Publ. 348, 41 p.
Delcourt, A. F., Dettmann, M. E., and Hughes, N. F., 1963: RevisiOn of some Lower
Cretaceous microspores from Belgium: Palaeontology, vol. 6, pt. 2, p. 282-92.
Dettmann, Mary E. and Playford, G., 1968, TaxonLmy of some Cretaceous spores and
pollen grains from eastern Australia: Proc. Royal Soc. Victoria, vol. 81,
pt. 2, p. 69-94.
Eisenack, Alfred and Klement, K. W., 1964, Katalog der fossilen Dinoflagellaten,
Hystrichosphaeren und verwandten Mikrofossiilien: Bd. 1 Dinoflagellaten,
E. Schweizerbart sche Ver~agsbuchhandlung, Stuttgart, 888 p.
Evitt, William R., 1969, Dinoflagellates and other organisms in palynological
preparations: in Aspects of Paiynology, Tschudy, R. H. and Scott, R. A.,
Wiley-Interscience, New York, p. 439-79.
Hughes, N. F., 1969, Jurassic and Early Cretaceous pollen and spores: in Tschudy
and Scott, Aspects of Palynology, Wiley Interscience, New York, p. 311-29.
Leffingwell, Harry A., 1971, Palyno!ogy of the Lance (Late Cretaceous) and Fort'
Union (Paleocene) formations of the type Lance area, Wyoming: Geol. Soc.
Am. Sp. Paper 127, p. 1-64.
Leopold, Estella B., 1969, Late Cenozoic Palynology: zn Tschudy and Scott,
Aspects of Palyno!ogy, Wiley Interscience, New York, p. 377-438.
Manum, Svein and Cookson, Isabel C., 1964, Cretaceous micropiankton in a sample
from Graham Island, Arctic Canada, collected during the second "Fram"-
Expedition (1898-1902): Skrifterutgitt av der norske Videnskaps-Akademi i
Oslo, Ny Serie, no. 17, 36 p .....
(con~'d.)
BIBLIOG?~,PHY
(cont'd.)
McGregor, D. C., 1965, Illustrations of Triassic, Jurassic, and Lower Cretaceous
spores and pollen of Arctic Canada: Geol. Surv. Canada, paper 64-55, 32 p.
Ne~fman, Karl Robert, 1963, Micropaleontology and stratigraphy of Late Cretaceous
and Paleocene formations, northwestern Colorado: U. Microfilms, Ann Arbor,
95 p.
Norton, Norman James, 1964, Palynology of the Upper Cretaceous and Lower Tertiary
in the type lpcality of the Hell Creek Formation: U. Microfilms, Ann Arbor,
175 p.
Panella, Giorgio, 1966, Palynology of the Dakota Group and Graneros Shale of the
Denver Basin: U. Microfilms, Inc., Ann Arbor, 173 p.
Penny, John S., 1969, Late Cretaceous and Early Tertiary palynology: in Tschudy
and Scott, Aspects of Palynology, Wiley Intersci~nce, New York, p. 331-76.
Pierce, Richard L., 1961, Lower Upper Cretaceous plant microfossils from Minnesota,
Minn. Geol. Survey Bull. 42, 86 p.
Playford, Geoffrey, 1965, Plant microfossils from Triassic sediments near Poatina
Tasmania: Jour. Geol. Soc. Australia, vol. 12, pt. 2, p. 173-210.
Playford, G. and Cornelius, K. D., 1967, Palynological and lithostratigraphic
features of the Razorback Beds, Mounta Morgan District, Queensland: U.
Queensland Papers vol. 6, no. 3, p. 81-94.
Playford, G. and Dettmann, Mary E., 1965, Rhaeto-Liassic plant microfossils from
the Leigh Creek Coal Measures, South Australia: Senckenbergiana, vol. 46,
nos. 2/3, p. 127-81.
Reiser, R. F. and Williams, A. J.,. 1969, Paiynoiogy of the lower Jurassic sediments
of the northern Sufat Basin, Queensland: Geol. Survey Queensland Publ. 339,
25 p.
Ross, N. E., 1949, On a Cretaceous pollen, and spore bearing clay of Scania: Bull.
Geol. Inst. Uppsala, vol. 34, p. 25-43.
Rouse, Glenn E., 1957, The application of a new nomenclatural approach to Upper
Cretaceous plant microfossils from western Canada: Can. Jour. Bot., vol. 35,
p. 349-375.
, 1959, Plant m~crofossils from Kootenay coal measures strata of British
Columbia: Micropaleontology, vol. 5, no. 3, p. 303-24.
, 1962, Plant microfossils from the Burrard Formation of western British
Columbia: Micropaleontology, vol..8, no. 2, p. 187-218.
Rouse, Glenn E., Hopkins, Jr., W. S. and Piel, K. M., 1971, Palynology of some
Late Cretaceous and Early Tertiary deposits in British Columbia and adjacent
Alberta:. Geol. Soc. Am. Sp. Paper 127, p.'213-246.
(cont'd.)
B IBLIOGP~iPHY
(cont'd.)
Sarjeant, William Antony S., 1967, The stratigraphical distribution of fossil
dinoflagellates: Rev. Paleobot. Palynology, vol. 1, nos. 1-4, p. 323-43.
Singh, Chaitanya, 1964, Microflora of the Lower Cretaceous Manville Group, east-
central Alberta: Research Council Alberta Bull. 15, 148 p..
Snead, Robert G., 1969, Microfloral diagnosis of the Cretaceous-Tertiary bounda~:
Research Council Alberta Bull. 25, 148, p.
Stanley, Edward A., 1960, Upper Cretaceous and Lower Tertiary sporomorphae from
northwestern South Dakota: U. Microfilms, Ann Arbor, 346 p.
, 1968, Upper Cretaceous and Paleocene plant microfossils and Paleocene
dinoflagellates and hystrichosphaerids from northwestern South Dakota: Bull.
Am. Paleontology, vol. 49, no. 222, p. 177-384.
Tschudy, Bernadine D., 1969, Species of Aquiiapollenites and Fibulapollis from
two Upper Cretaceous localities in Alaska: U.S.G.S. Prof. Paper 643-A, 17 p.
Weyland, H. and Krieger, W., 1953, Die Sporen und Pollen der Aachener Kreide
und ihre Bedeutung ruer die Chrakterisierung des Mittleren Senons: in
Catalog of Fossil Pollen and Spores, vol. 2, Pennsylvania State University.
PLATE
Polaroid Photomicrographs of Palynomorphs
Figure 1. Sequoia sp., sample 500-10, 40 microns.
2. Sequoiapollenites Ra!eocenicus Stanley 1965, sample 1750-50,
30 microns.
3. Podocam~us maximus Stanley 1965, sample 1500-10, 63 microns.
4. Sphagn.um. megium Drozhastichich 1961, sample 1750-60, 28 microns.
5. Wodehouseia spina~a Stanley 1960, sample 2300-10, 62 microns.
6. Wodehouseia spinata Stanley 1960, sample 2300-10, 60 microns..
?. Wodehouseia sp.inata Stanley 1960, sample 2300-10, 81 microns.
8. A~uilapollenite? sp., sample 2?50-60, 80 microns.
9. Aqui~apollenites sp., sample 2750-60, 96 microns.
10. Aquilapollenites senonicus (Mtchedlishvili) Tschudy and Leopold
1969, sample 2?50-60, 35 microns. .
11. Rugutriletes sp., sample 4750-60, 47 microns'.
12. Leptolepidites sp., sample 4?50-60, 75 microns.
PLATE 2
Polaroid Photomicrographs of Paiynomorphs
Figure 1. Deflandrea rectangularis Cookson and Eisenack 1962, sample 4750-60,
118 microns.
2. 'Gymnodinium.sp., samp%e 5250-60, 35 microns.
8. Hys~tricho~phaeridium readei Downey, Sarjeant and Williams i961,
sample 5750-60, 100 microns..
4. Striatites striatus Pierce 1961, sample 7250-60, 75 microns.
5. Sphagnumsporites a.nti, quasporites (Wilson and Webster) Brenner 1963,
sample 7500-10, 25 microns.
6. Hemitelia mirabilis Bolkhovitina 1953, sample 7500-10, 35 microns.
7, Gonyaulax apionis Cookson and Eisenack 1962, sample 7750-60,
98 microns.
8. Scriniodinium ca~panu!a Gockt 1959, sample 9750-60, 105 microns.
9. Gonyaulax jurassica Deflandre 1938,. sample 11,240-50, 94 microns.
--lC-
~H !!!111 ! Iil~o&'o
~o- ,' '-' ~~LI_~~LLi-!~_[_I_
L. ......... ..F ..... !!J !J~-I-i-i--i
~1 I I
III I I ! I I I 1 I!~ooo-~o
, · I I i
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~°i' "iTN__i i i il ITt-I-
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L. ~LL!~_._ ~~!._J_j I I I
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2o
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.,
.
-it
,c h,,'~-~.~ ir: ,-'. rc. lative abundance of major spore Eroups.
- 9-
120-
1000-
Pleistocene?
· 'Eocene?
Eocene
.... Paleocene
Paleocene
- Maestrichtian
..~e strlc brian
, ~ampanian
, Campanian
4P50-
4750-
5?5o-
575o-
6210-
6700-
725o-
7500-
7750-
8250- ,Albian
8760- --Marine --^lbian
9250- --Marine--
9750- --MarS_ne--^ptian?
-- Marine --Santonian
-- Marine --Santonian
·
-- Marine --Santonian
-- Marine --Cenomanian
,,Cenomanian
-- Mari ne --Ce nomanian
-- Marine --A!bian
--Marine --Albian
lO, 500-
10,75~-
11,240-
!i,
12,9~a~'
13 ,!50 .....
1
- Ma ri ne
--',farine
->:ari ne
!~.,ptian?
~faute rivian?
--~ ~,:='.e ,;urass :. c?
,~.f.*.,~re !. -- Gra~h of susie ,~ ..... ;:~. well,