900 difference in declination is due to rapid changes in the References paleomagnetic field with respect to Antarctica during the Lower Paleozoic cannot be discounted at the present level Alley, R. B., and Watts, D. R. 1979. Paleomagnetic investigation of of coverage. A solid data base from the Paleozoic of the east the northern antarctic peninsula. EQS. Transactions, American antarctic craton will be required before the problem is fully Geophysical Union, 60, 240. resolved. Furthermore, the results for the Ellsworth Moun- Dalziel, I. W. D. In press. The pre-Jurassic history of the Scotia Arc: tains presented here represent only 3 sites of the total of 70. A review and progress report. In C. Craddock (Ed.), Antarctic At this stage in the investigation, the data are most consis- Geoscience. Madison: The University of Wisconsin Press. deWit, M. J 1977. The evolution of the Scotia Arc as a key to the re- tent with a theory proposing a microplate nature of West . construction of southwestern Gondwanaland. Tectonophysics, 37, Antarctica. 53-82. Elliot, D. H., Watts, D. R., Alley, R. B., and Gracanin, T. M. 1978. Geo- logic studies in the northern antarctic peninsula, R/V Hero cruise 78-lB. February 1978. Antarctic Journal of the U.S., 13(4), 12-13. Elston, D. R., and Purucker, M. E. 1979. Detrital magnetization in 50 Sr ndon. red beds of the Moenkopi Formation (Triassic), Gray Mountain,

C>. Arizona. Journal of Geophysical Research, 84, 1653-1666. EAST Graham, J. W. 1949. The stability and significance of magnetism in ANTARCT IC - CRATON sedimentary rocks. Journal of Geophysical Research, 59, 131 137. Manzoni, M., and Nanni, T. JIIM,"IMInI 1977. Paleomagnetism of Ordovician 90 W - • -90•E Lamprophyres from Taylor Valley, Victoria Land, Antarctica. EIGHTS C) Ellsworth Minny S tation COAST O) Mine I Pure and Applied Geophysics, 115, 961-978. McQueen, D. M., Scharnberger, C. K., Scharon, L., and Halpern, M. 0 1972. Cambro-Ordovician paleomagnetic pole position and Taylor Valley rubidium-strontium total rock isochron for charnockitic rocks 13"0 LAND !^Q from Mirnyy Station, East Antarctica. Earth and Planetary Science Letters, 16, 433-438. Schopf, J. M. 1969. Ellsworth Mountains: Position in West Antarc- ISO. tica due to sea floor spreading. Science, 164, 63-66. Figure 2. Map showing major crustal units of Antarctica with Stump, E. 1976. On the late Precambrian-early Paleozoic metasediments mean declinations of paleomagnetic vectors from Upper! and metasedimentary rocks of the Queen Maud Mountains, Antarc- Late Cambrian and Early Ordovician rocks. The result from tica, and a comparison with rocks of similar age from southern Africa the Ellsworth Mountains is approximately 900 different from (Report 62). Columbus: The Ohio State University, Institute of those of the east antarctic craton. Polar Studies. Watts, D. R. In press. Potassium-argon and paleomagnetic results This research was supported by the Scott Turner Fund of from King George Island, South Shetland Islands. In C. Crad- the University of Michigan and by National Science Foun- dock (Ed.), Antarctic Geoscience. Madison: The University of Wis- Foundation grant DPP 78-21730. The authors wish to thank consin Press. Rob Van der Voo for providing facilities at the Univer- Zijderveld, J. D. A. 1968. Natural remanent magnetizations of some sity of Michigan for the preliminary study of unoriented intrusive rocks from the Sor Rondane Mountains, Queen Maud samples. Land, Antarctica. Journal of Geophysical Research, 73, 3773-3785.

Geological investigations The most ambitious field project of the 1979-80 austral summer season in Antarctica was conducted in the Ells- and logistics in the worth Mountains between 3 December and 12 January. The Ellsworth Mountains, 1979-80 area studied included both the Sentinel Range (north) and the Heritage Range (south), from about 77 0 15S to 80°30S latitude and 80°W to 87°30W longitude (see figure 1). The JOHN F. SPLETrSTOESSER camp, Ellsworth Camp (also known as Camp Macalester), was located adjacent to Minnesota Glacier at 79°05S Minnesota Geological Survey 85°58W, about midway between the northern and south- University of Minnesota ern extremities of the mountains. Camp elevation was St. Paul, Minnesota 55108 about 1,250 meters above sea level. This was the largest field program in the Ellsworth GERALD F. WEBERS Mountains in the 20-year history of studies there. Partici- Macalester College pating were 42 scientists and technicians representing eight St. Paul, Minnesota 55105 countries (U.S., 28; West Germany and New Zealand, 4

36 ANTARCTIC JOURNAL ma transportation to outcrop areas that could be reached on 1-day trips. The scientific projects conducted during the field season are summarized in table 1. The largest contingent of scien- po, M1ULMA tific personnel, under the direction of C. F. Webers, included

- numerous senior investigators studying a variety of topics related to a comprehensive analysis of the geology of the

---

ROW" 71777

\! VINSON MASSIF -0 /fr •. cy I

CAMPMLES1ER GLACEP

l4 Af

ELLSWORTH ! - MOUNTAINS / Figure 2. UK-IN helicopter at Polarstar Peak (left) and Mt. Qç Ulmer (right) in northern Sentinel Range, about 100 nautical miles from base camp.

Ellsworth Mountains. The goals were: (1) to conduct a de- tailed study of significant areas that composed parts of the Figure 1. Location map of the Ellsworth Mountains (modified 13,000-meter stratigraphic section of the Ellsworths; (2) to from Figure 1 in Craddock, Anderson, and Webers 1964). obtain extensive collections of the fossil floras and faunas throughout the stratigraphic section for correlative, envi- each; England, 2; Japan, Norway, Switzerland, and the ronmental, and evolutionary study; (3) to examine the evo- U.S.S.R., 1 each). lution of landforms beginning with a probable Jurassic Scientific priorities were determined by C. F. Webers, uplift through continental glaciation and partial recession; and flight schedules for the three UH-1N turbine ("Huey") (4) to chart the sequence of major structural geologic events helicopters (figure 2) were made up daily by J . F. Splett- in the area; (5) to analyze the tectonic relationship of the stoesser. A total of 353 helicopter hours were flown during Ellsworths to the Antarctic Peninsula and to the East Ant- the season in direct support of science projects. The flying arctic Shield; and (6) to obtain information on the nature operation was under the command of LCDR W. Ferrell from and composition of a variety of igneous rocks exposed in 3 December to 26 December, and under LCDR D. Ellison the Heritage Range. thereafter. These goals were accomplished. The success of the pro- - The camp, constructed by personnel employed by gram was due largely to the helicopter support, which per- Holmes and Narver, Inc., consisted of five Jamesway build- mitted a large amount of research within a relatively large ings. The Holmes and Narver camp manager for the season area. All stratigraphic units exposed in the Ellsworth was David Waidrip. Mountains were studied in detail for paleoecological, pale- Many geologic investigations were conducted using the ontological, sedimentological, and stratigraphic character- main camp as a base of operations. For long-term studies in istics. The Whiteout Conglomerate was found to contain remote areas, tent camps were established. A total of 15 stratified sediments at two stratigraphic positions and to different camp sites were occupied during the period from contain boulder pavements. Crashsite Quartzite stratigra- 11 December to 10 January. Up to 22 people were in a phy will be extended to the Heritage Range and modified. maximum of six camps at one time. Most of the field studies The Heritage Group will be subdivided into a number of in the areas of tent camps were conducted on foot, but often new units. The Minaret Group was found to overlie the the local topography and distances prevented this and heli- Heritage Group. No major unconformities (except for copters transported investigators to critical outcrops. Ski- boulder pavements) were found anywhere in the strati- doos were also used in remote field operations for local graphic column. Table 2 shows a tentative stratigraphic

1980 REvIEw 37 column compared with Craddocks (1969) and Hjelle, Ohta, data indicate a major rotation of the Ellsworth Mountains and Winsnes (1978). Seven new faunas of Middle and block. All known igneous rocks in the Ellsworth Moun- Late Cambrian age, and one of Devonian age, were found. tains were collected for further study. Landform sequences Previously known faunas and the Glossopteris flora were were examined and paleo-karst features were studied and re-collected. A single major deformational phase oc- collected. curred in the Late Triassic-Early Jurassic, as was previ- This project was supported by National Science Founda- ously known. Possible smaller scale deformations and their tion grant DPP 78-21720 to Macalester College, St. Paul, timing are being evaluated. Preliminary paleomagnetic Minnesota.

Table 1. Summary of scientific investigations in the Ellsworth Mountains, 1979-80

Helicopter hours flown Number in in support Dates Scientific project Principal investigator party of project In field

Comprehensive geologic study G. F. Webersb 24 177.8 Dec. 3-Jan. 17 Glacial history G. Dentond 6 102.5 Dec. 3-Jan. 11 Evolution of West Antarctic-Andean Cordillera I. Daiziel 2 Dec. 20-Jan. 17 Geodetic control D. Knutzen9 3 48.7 Dec. 3-Jan. 11 Radiometric survey E. Zeller" 4 11.7 Dec. 12-Dec. 19 Meteorite search W. Cassidy 3.5 Dec. 20-Dec. 26 Soil development I. Campbell/G. Claridge 2 8.8 Dec. 9-Dec. 18

Total 42 353.0

C Includes foreign exchange scientists. Included with Webers total. Test flights and other flying not directly associated with science support raised this total to 364.1 hours. Time periods for individual field personnel varied. b Other personnel were J. Anderson, A. Bramall, W. Buggisch, J. Collinson, C. Craddock, J. Craddock, P. von Gizycki, P. Gould, C. Hudak, C. Matsch, A. Ojakangas, J. Pojeta, L. Rosen, A. Rutford, V. Samsonov, J. Splettstoesser, B. Sporli, C. Vavra, W. Vennum, D. Watts, E. Yochelson, M. Yoshida, and J. Zawiskie. d Other personnel were B. Andersen, J. Bockheim, H. Conway, J. Leide, and M. Prentice. Other Investigator was M. Thomson. Other personnel were T. Henderson and R. Pearsall. "Other personnel were K. Bulla, G. Dreschhoff, and V. Thoste.

References Craddock, C., Anderson, J. J., and Webers, G. F. 1964. Geologic outline of the Ellsworth Mountains. In R. J. Adie (Ed.), Antarctic geology, Proceedings of the First International Symposium on Antarc- Craddock, C. 1969. Geology of the Ellsworth Mountains. In V. C. tic Geology, Cape Town, 1963. Amsterdam: North-Holland. Bushnell and C. Craddock (Eds.), Geologic maps of Antarctica (Ant- Hjelle, A., Ohta, Y., and Winsnes, T. S. 1978. Stratigraphy and arctic map folio series, folio 12, plate 4). New York: American igneous petrology of southern Heritage Range, Ellsworth Moun- Geographical Society. tains, Antarctica. Norsk Polarinstitutt Skrifter, 169, 5-43.

38 ANTARCTIC JOURNAL NO

Table 2. Generalized Geologic Sections in the Ellsworth Mountains

Craddock 1969 Hjelle, Ohta, and Winsnes 1978 Tentative section, this paper

Thickness, Thickness, Thickness, Age Formation meters Age Formation meters Age Formation meters

Polarstar Formation Not discussed Polarstar Formation Permian Interbedded slate, argillite, 1,370 Permian Interbedded slate, argillite, 1,370 quartzite, graywacke, coal quartzite, graywacke, coal Whiteout Conglomerate Whiteout Conglomerate 400+ Whiteout Conglomerate Permo- Unsorted bouldery gray- 915 Permo- Black diamictite (tillite) 915 Carbon- wacke (Marine tillite?) Carbon- iferous (?) interous

Crashsite Quartzite Crashsite Quartzite Crashsite Quartzitec Devonian Upper Dark Member 305 Mid- White, gray, and green Devonian Upper Dark Member 305 and older Brown micaceous quartzite Paleozoic quartzites to Upper Brown micaceous quartzite Cambrian Middle Light Member 1,070 Upper Dark Member— Middle Light Member 1,070 White, gray and buff not seen White, gray and buff quartzite quartzite Lower Dark Member 1,830 Middle Light Member 800-850 Lower Dark Member 1,830 Green and buff quartzite, Green and buff quartzite, argillite Lower Dark Member 750-1,000 argillite Heritage Group Cambrian Dunbar Ridge Formation Minaret Formation Cambrian Phyllite, argillite, slate, 6,710 and Middle Slate and black 700-1,200 Upper Marble, minor conglomerate, 0-800 and Pre- quartzite, conglomerate, Cambrian calcareous shale Cambrian "breccia bodies" cambrian (?) minor marble, lava flows Heritage Group Heritage Groupd Middle Edson Hills Formation 3,500 Upper Phyllite, argillite, black shale, 7,000 Cambrian Volcanic-clastic sequence Cambrian limestone, conglomerate, or older and Middle polymictic and diamictic Cambrian conglomerates, lava flows, Minaret Group Middle Horseshoe Formation 500 marble, quartzite, graywacke Pre- Marble, minor conglomerate, 975 Precambrian Volcanic-calcareous sequence cambrian (?) "breccia bodies" TOTAL 13,175 Minaret Group TOTAL 13,290 a Based on southern Heritage Range only. b Sentinel Range only; Heritage Range undivided. Crashsite stratigraphy will be extended/ modified to the Heritage Range. Heritage Group will be subdivided into new formations and members.

0