ward extension of the Lassiter Coast Intrusive Suite. We alsoconclude that the granitic rocks exposed throughout the entiresouthern Antarctic Peninsula and eastern Ellsworth Land rep-resent a consanguineous suite of magmas formed in a mag-matic arc that developed in response to subduction of the Pa-cific Ocean plate along the western edge of the southernAntarctic Peninsula.

In addition to the authors, the field party included Karl S.Kellogg, David J . Lidke, and J . Michael O'Neill of the U.S.Geological Survey and exchange scientist Janet W. Thomson ofthe British Antarctic Survey. The party was placed in the fieldby LC-130 Hercules aircraft of the U.S. Navy's Antarctic Devel-opment Squadron Six on 11 December 1984 and was evacuatedon 5 February 1985. This research was supported by NationalScience Foundation grant DPP 83-18183 to the U.S. GeologicalSurvey. A previous version of this manuscript benefitted froma review by Karl S. Kellogg.

References

Gee, C.T. 1989. Permian glossopteris and elatocladus megafossil florasfrom the English Coast, eastern Ellsworth Land, Antarctica. AntarcticScience, 1(1), 35-44.

Halpern, M. 1967 Rubidium-strontium isotopic age measurements ofplutonic igneous rocks in eastern Ellsworth Land and northern Ant-arctic Peninsula, Antarctica. Journal of Geophysical Research, 72(20),5138-5142.

Kellogg, K.S. 1986. Personal communication.Lambert, R.S.J., and J.G. Holland. 1974. Yttrium geochemistry applied

to petrogenesis utilizing calcium-yttrium relationships in mineralsand rocks. Geochemica et Cosmochimica Acta, 38, 1393-1414.

Laudon, T.S., L.L. Lackey, ED. Quilty, and EM. Otway. 1970. Geologyof eastern Ellsworth Land. In V.C. Bushnell and C. Craddock (Eds.).Geologic maps of Antarctica, Antarctic Map Folio Series 12(3). New York:American Geographic Society.

Laudon, T.S., D.J. Lidke, T. Delevoryas, and C.T. Gee. 1987 Sedimen-tary rocks of the English Coast, eastern Ellsworth Land, Antarctica.In G.D. McKenzie (Ed.) Gondwana Six: Structure, tectonics and geophys-ics. (Monograph 40). Washington, D.C.: American GeophysicalUnion.

Nakamura, N. 1974. Determination of REE, Ba, Mg, Na and K in car-bonaceous and ordinary chondrites. Geochemica et Cosmochimica Acta,38, 757-775.

O'Neill, J.M., and J.W Thomson. 1985. Tertiary mafic volcanic andvolcaniclastic rocks of the English Coast, Antarctica. Antarctic Journalof the U.S., 20(5), 36-38.

Pankhurst, R.J., and PD. Rowley. 1991. Rb-Sr study of Cretaceous plu-tons from southern Antarctic Peninsula and eastern Ellsworth Land,Antarctica. In M.R.A. Thomson, J.A. Crame and J.W. Thomson(Eds.), Geological evolution of Antarctica. Cambridge: Cambridge Uni-versity Press.

Pearce, J.A., N.B.W. Harris, and A.G. Tindle. 1984. Trace element dis-crimination diagram for the tectonic interpretation of granitic rocks.Journal of Petrology, 25, 956-983.

Rowley, PD., W.R. Vennum, K.S. Kellogg, T.S. Laudon, P.C. Carrara,J.M. Boyles, and M.R.A. Thomson. 1983. Geology and plate tectonicsetting of the Orville Coast and eastern Ellsworth Land, Antarctica.In R.L. Oliver, P.R. James and J.B. Jago (Eds.), Antarctic earth sciences.Canberra: Australian Academy of Sciences.

Rowley, PD., K.S. Kellogg, and W.R. Vennum. 1985. Geologic studiesin the English Coast, eastern Ellsworth Land, Antarctica. AntarcticJournal of the U.S., 20(5), 34-36.

Rowley, ED., K.S. Kellogg, W.R. Vennum, T.S. Laudon, J.W. Thomson,J.M. O'Neill, and D.J. Lidke. 1991. Tectonic setting of the EnglishCoast, eastern Ellsworth Land, Antarctica. In M.R.A. Thomson, J. A.Crame and J.W. Thomson (Eds.), Geological evolution of Antarctica.Cambridge: Cambridge University Press.

Saunders, A.D., S.D. Weaver, and J. Tarney. 1982. The pattern of Ant-arctic Peninsula plutonism. In C. Craddock (Ed.), Antarctic Geoscience.Madison: University of Wisconsin Press.

Shapiro, L., and WW. Brannock. 1962. Rapid analysis of silicate, carbonateand phosphate rocks. U.S. Geological Survey Bulletin 1144-A. Washing-ton, D.C.: U.S. Government Printing Office.

Streckeisen, A.L. 1976. To each plutonic rock its proper name. EarthSciences Review, 12, 1-33.

Vennum, WR., and ED. Rowley. 1986. Reconnaissance geochemistryof the Lassiter Coast Intrusive Suite, southern Antarctic Peninsula.Geological Society of America Bulletin, 97, 1521-1533.

Eocene terrestrialpalynology of

Seymour Island

ROSEMARY A. ASKIN

Department of Earth SciencesUniversity of California

Riverside, California 92521

Terrestrial palynofloras preserved on Seymour Island reflecta shift to Nothofagus-dominated vegetation during the earlyEocene in the northern Antarctic Peninsula region. In contrast,the preceding late Cretaceous and Paleocene palynofloras aredominated by podocarpaceous conifers, especially Phyllocladi-dites mawsonii, and Nothofagidites pollen are diverse but usually

a minor part of the flora (Askin 1990). Conifers remain an im-portant part of the Eocene vegetation; however, they are oftena subdominant part of the palynoflora or match Not hofagiditespollen in abundance.

Eocene strata on Seymour Island are included in the La Mes-eta Formation, a complex array of deltaic marine, lenticularsandy sediments grouped into seven members (Telm 1 to 7,Sadler 1988). The basal part is probably upper Lower Eocene(Harwood 1988; Wrenn and Hart 1988; summarized in Askin etal. 1991), and the main part of the formation is Middle andUpper Eocene (e.g., Zinsmeister and Camacho 1982; Wrennand Hart 1988). Current palynological research concentrates onterrestrial palynomorphs (spores and pollen from land plants)in about 500 samples from sections around the meseta. Marinedinoflagellate cyst assemblages from the middle and upper partof the formation were described by Wrenn and Hart (1988).

Nothofagidites pollen are particularly prominent in the lowerpart of the La Meseta Formation and include common Not hofag-idites matauraensis (Couper) Hekel (brassii group) and N. saraen-

44 ANTARCTIC JOURNAL

1

2,

0

sis Menéndez and Caccavari (fusca group; synonomy and com-parisons discussed in Dettmann et al. 1990), infrequent N.asperus (Cookson) Romero (menziesii group), rare N. cf. spinosus(Couper) Mildenhall and Pocknall (brassii group), and variousother species (figure). Not hofagidites pollen, including N. saraen-sis, are also common in lower Eocene samples from KingGeorge Island, South Shetland Islands (Torres and Meon 1990).

Besides Nothofagus and conifers, the Seymour Island Eocenefloras are rich in Proteaceae, similar to the Campanian to Pa-leocene succession. Many of the proteaceous species, and otherangiosperm species that evolved during the late Cretaceous,continued through into the Eocene; however, a variety of an-giosperm taxa make their first appearances in the Eocene. Inthis epoch, the last land connections between Antarctica andSouth America were probably severed. Active immigration oremmigration to or from Antarctica would still be possible dur-ing the Eocene for species with relatively rapid dispersal ca-

pabilities but only during low sea-level stands, although dis-persal might also be possible for species whose seeds couldsurvive oceanic (or bird) transport. Mapping of occurrences ofplant taxa on Seymour Island, South Shetland Islands, andsouthern South America may help elucidate the Paleogene pa-leogeography of this region, especially scrutiny of taxa such asNothofagus that probably would have required continuous landconnections over a relatively long time for dispersal.

This work is supported by National Science Foundation grantDPP 90-19378.

References

Askin, R.A. 1990. Campanian to Paleocene spore and pollen assem-blages of Seymour Island, Antarctica. Review of Palaeobotany and Pa-lynology, 65, 105-113.

ii 3

¼rrAt

5 6 7Photomicrographs of Nothofagidites pollen from the lower La Meseta Formation, Seymour Island. Magnification x 1250 (bar is equivalentto 10 microns). 1. Nothofagidites waipawaensis (Couper) Fasola, sample A3-04/microslide 1; 2. Nothofagidites cf. spinosus (Couper) Mit-denhall & Pocknall, C1-15/1; 3. Nothofagidites cf. SpifloSUS, C2-07/11; 4. Nothofagidites asperus (Cookson) Romero, A3-04/1; 5. Not hofagiditessaraensis Menéndez & Caccavari, C2-01/1; 6. Nothofagidites matauraensis (Couper) Hekel, A3-04/1; 7. Nothofagidites dorotensis Romero,B5-08/1.

1991 REVIEW 45

Askin, R.A., D.H. Elliot, J.D. Stilwell, and W.J. Zinsmeister. 1991. Stra-tigraphy and Paleontology of Campanian and Eocene sediments,Cockburn Island, Antarctic Peninsula. South American Journal of EarthSciences, 4(1/2), 99-117

Dettmann, M.E., D.T. Pocknall, E.G. Romero, and M. del CarmenZamaloa. 1990. Nothofagidites Erdtman ex Potonié, 1960; a catalogueof species with notes on the paleogeographic distribution of Notho-fagus BI. (Southern Beech). New Zealand Geological Survey PaleontologicalBulletin, 60, 1-79.

Harwood, D.M. 1988. Upper Cretaceous and Lower Paleocene diatomand silicoflagellate biostratigraphy of Seymour Island, eastern Ant-arctic Peninsula. In R.M. Feldmann and M.O. Woodburne (Eds.),Geology and paleontology of Seymour Island, Antarctic Peninsula. (Geolog-ical Society of America Memoir 169.) Boulder, Colorado: GeologicalSociety of America.

Sadler, P.M. 1988. Geometry and stratification of uppermost Creta-ceous and Paleogene units on Seymour Island, northern Antarctic

Peninsula. In R.M. Feldmann and M.O. Woodburne (Eds.), Geologyand paleontology of Seymour Island, Antarctic Peninsula. (Geological So-ciety of America Memoir 169.) Boulder, Colorado: Geological Societyof America.

Torres, T., and Meon, H. 1990. Preliminary palynological study of FossilHill, Fildes Peninsula, King George Island, Antarctica. Serie CientificaINACH, 40, 21-39. (In Spanish)

Wrenn, J.H., and G.F. Hart. 1988. Paleogene dinoflagellate cyst bio-stratigraphy of Seymour Island, Antarctica. In R.M. Feldmann andM.O. Woodburne (Eds.), Geology and paleontology of Seymour Island,Antarctic Peninsula. (Geological Society of America Memoir 169.) Boul-der, Colorado: Geological Society of America.

Zinsmeister, WJ., and H.H. Camacho. 1982. Late Eocene (to possiblyearliest Oligocene) molluscan fauna of the La Meseta Formation ofSeymour Island, Antarctica Peninsula. In Craddock (Eds.), Antarcticgeoscience. Madison: University of Wisconsin Press.

Geological fieldworkon Deception Island

and King George Island,South Shetland Islands

RANDALL A. KELLER

College of OceanographyOregon State UniversityCorvallis, Oregon 97331

On 6 January 1991, the Fourth Polish Geodynamical Expedi -tion to West Antarctica departed Montevideo, Uruguay aboardthe ocean-going tug Neptunia (Polish Ship Salvage Company,Gdynia). By kind invitation of Aleksander Guterch (Institute ofGeophysics, Polish Academy of Sciences, Warsaw) and Krzysz-tof Birkenmajer (Institute of Geological Sciences, Polish Acad-emy of Sciences, KrakOw), I was able to participate in thatexpedition.

The expedition spent 6 weeks in the Bransfield Strait andSouth Shetland Islands conducting geophysical surveys andgeological fieldwork at various locations. I was a member of ageological field party that spent 17 days on Deception Island,a large volcano in the Bransfield Strait (figure). All of DeceptionIsland is thought to be less than 700,000 years old, and manyareas are still warm from volcanic eruptions as recent as 1970(Smellie 1988). Professor Birkenmajer mapped the geology ofthe island while I collected samples of volcanic rocks for geo-chemical and petrological analyses (see Keller, Fisk, and White,Antarctic Journal, this issue).

Our field party then moved to the area of Lions Rump onKing George Island (figure) for 14 days. This area containsexposures of glacial sediments interbedded with volcanic arcrocks of Tertiary age and has been the subject of intense geo-logical study (e.g., Porebski and Gradzinski 1987; Birkenmajer,Soliani, and Kawashita 1989). I sampled some of the volcanicarc rocks for geochemical analyses and comparison to our sam-ples from the younger volcanoes (such as Deception Island)associated with extension in the Bransfield Strait (see Keller,Fisk, and White, Antarctic Journal, this issue).

62W

DRAKEPASSAGE

King Georgelid T2

Lions_

V50 km

VL

AV

2ep.,ion 63S

iEEL occI::t::3Geography and bathymetry of the Bransfield Strait region. Landareas are shaded. Bathymetry contoured in kilometers (km). Lo-cations of 1990-1991 geological fieldwork described in this articleare Deception Island and Lions Rump on King George Island.

This work was supported by a Fulbright Research Fellowshipfrom the U.S. Information Agency, and National Science Foun-dation grant DPP 88-17126 to M.R. Fisk.

References

Birkenmajer, K., E. Soliani, Jr., and K. Kawashita. 1989. Geochronologyof Tertiary glaciations on King George Island, West Antarctica. Bul-letin of the Polish Academy of Sciences, Earth Sciences, 37, 27-48.

Keller, R.A., M.R. Fisk, and W.M. White. 1991. Geochemistry of Qua-ternary volcanism in the Bransfield Strait and South Shetland Is-lands: Preliminary results. Antarctic Journal of the U.S., 26(5).

Porebski, S.J., and R. Gradzinski. 1987 Depositional history of thePolonez Cove Formation (Oligocene), King George Island, West Ant-arctica: A record of continental glaciation, shallow-marine sedimen-tation and contemporaneous volcanism. Studia Geologica Polonica,93(7), 7-62.

Smellie, J.L. 1988, Recent observations on the volcanic history of De-ception Island, South Shetland Islands. British Antarctic Survey Bulle-tin, 81, 83-85.

46 ANTARCTIC JOURNAL