Maximum ground temperatures measured in warm ground areas in 1972 (after Lyon and Giggenbach 1974) and 1983

Warm ground area 1 Warm ground area 2 Maximum Depth of Maximum Depth of temperature measurement temperature measurement

Date measured (©C) (in centimeters) measured ( CC) (in centimeters)

20, 21 January

1983 +20.5 15 58.0 10 15, 16 December

1972 +21.0 15 59.0 25

This work was supported by the captain, officers, and crew of Journal of Geology and Geophysics, 10(2), 418-421. USCGC Glacier during Deep Freeze 83, to whom we are most Giggenbach, W. F. 1976. Geothermal ice caves on Mt. Erebus, Ross grateful. The research was supported by National Science Foun- Island, Antarctica. New Zealand Journal of Geology and Geophysics, 19(3), dation grants DPP 80-20002 and DPP 80-21402. Field personnel for 365-372. Lyon, C. L., and W. F. Giggenbach. 1974. Geothermal activity in Vic- this study were J. R. (Harry) Keys and W. C. McIntosh; they were in the field 20-21 January 1983. toria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 17(3), 511-521. Nathan, S., and F. J. Schulte. 1967. Recent thermal and volcanic activity on Mt. Melbourne, northern Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 10(2), 422-430. References Nathan, S., and F. J. Schulte. 1968. Geology and petrology of the Camp- bell Aviator Divide, northern Victoria Land, Antarctica. Part 1—Post Adamson, R. C., and R. J. Cavaney. 1967. Volcanic debris-layers near Paleozoic rocks. New Zealand Journal of Geology and Geophysics, 11, Mt. Melbourne, northern Victoria Land, Antarctica. New Zealand 940-975.

Geological observations on the Sculpture Mountain. The basal part of the basalt sequence and Kirkpatrick Basalt in the Mesa Range the contact with the underlying rocks were examined at Agate Peak, Mount Fazio, the Exposure Hill area, and in the upper region, northern Victoria Land reaches of the Aeronaut Glacier. Diabase intrusions crop out in the latter two areas. The maximum stratigraphic thickness of the Kirkpatrick D. H. ELLIOT, C. FAURE, T. M. MENSING, Basalt is estimated to be 900 meters. A small number of flows in M. A. SIDERs, M. A. HABAN, and E. M. CHERRY the Mesa Range can be used as stratigraphic markers to corre- late the lower part of the section. A unit of black basalt which Institute of Polar Studies forms a prominent feature in the Mesa Range is also present on Department of Geology and Mineralogy Sculpture Mountain and will facilitate the correlation of the The Ohio State University basalt sequences between the mesas and scattered nunataks of Columbus, Ohio 43210 the upper Rennick Glacier region. The basalts rest on volcanic breccias and volcanogenic sedi- mentary rocks that appear to be similar to the Mawson Diamic- A second season of fieldwork was conducted in the general tite of southern Victoria Land (Ballance and Watters 1971; Hall, area of the Mesa Range between 12 November and 17 December Sutter, and Borns 1982). These deposits were observed at the 1982 (see figure). The objectives for the 2-year field program base of Tobin Mesa, at the southern end of Gair Mesa, and at the included making stratigraphic studies; sampling for pe- head of the Aeronaut Glacier. At each of these locations, the trological, mineralogical, geochemical, and isotopic studies; Kirkpatrick Basalt disconformably overlies the volcaniclastic and collecting rocks for paleomagnetic investigations. rocks. At the southern end of Gair Mesa a sedimentary interbed Stratigraphic sections were measured at Mills Valley, Mount containing conchostracans is present near the base of the basalt Ballou, and Mount Masley on Pain Mesa; on Tobin Mesa; and on sequence. The Agate Peak locality, first described by Nathan

1983 REVIEW 11

basalt sequence. Tree stumps in situ were noted at several 1620E l64°E places. Observations during this field season support the conclusion, tentatively drawn last season (Elliot et al. 1982), that there is no compelling evidence for major faulting at the head of the Ren- nick Glacier between Exposure Hill and Vantage Hills. Nev- ertheless, a fault probably separates Sheehan Mesa from out- ayp Evans Nevé crops to the west and significant faulting undoubtedly occurs to in the north, along the Rennick Glacier.

Sculptur . Solo Petrographic examination and laboratory studies of the major Mtn and trace element composition of basalts and diabases, of the Silva qate Peak mineral chemistry, and of the isotopic composition of these Ridge) Q o2.Mt Manley rocks are in progress. Dating of the basalts by the argon-40/ 7305 Sheehan Half -Ration - Mesa óJ[Q argon-39 technique will also be attempted. The basalts and p o Névé diabases will be used to determine a paleomagnetic pole posi- d .6 Mills Valley °- &WILnTh ç tion, to establish a record of magnetic polarity reversals, and to ç\O S ? study the magnetic properties of the minerals. 0 V Bollou This study was supported by National Science Foundation

Y Tobin JIJ \ & H grant DPP 80-21401. ,Mesaf1IHJL QcP o

Q)Ml. Gair Meso flJJj

Petrogenesis of the Kirkpatrick Basalt, Anomalously high initial strontium-87/strontium-86 (87Sr/86Sr) ratios (greater than 0.710) for the Jurassic tholeiites Solo Nunatak, northern Victoria Land (approximately 170 million years old) of the Transantarctic Mountains have been well documented by Compston, McDougall, and Heier (1968); Faure (1981); Faure, Bowman, and Elliot (1979); Faure et al. (1972, 1974); Hoefs, Faure, and Elliot TERESA M. MENSING, (1980); Kyle (1980); and Kyle, Elliot, and Sutter (1980). These GUNTER FAURE, and KAREN S. TAYLOR rocks of the Ferrar Supergroup extend from northern Victoria Land to the Pensacola Mountains and are composed of dolerite Institute of Polar Studies intrusions (Ferrar Dolerite Group) and basalt lava flows The Ohio State University (Kirkpatrick Basalt Group). Major element data for these rocks Columbus, Ohio 43210 display normal differentiation trends when plotted on variation diagrams. That is, positive correlations exist between Si02 and Na2O, K20, Ti02, and P205 (Kyle 1980). Negative correlations are Lois M. JONES observed between S02 and calcium oxide (CaO), magnesium oxide (MgO), and aluminum oxide (Al 20) (Kyle 1980). CONOCO Inc., Two petrogenetic models have been proposed to explain the Research and Development Department observed isotopic and chemical trends for these rocks: (1) con- Ponca City, Oklahoma 74603 tamination of mantle-derived melts by the assimilation of crust-

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