more Glacier area, Antarctica. Columbus, The Ohio StateUniversity, Institute of Polar Studies. Report, 34. 132p.

Barrett, P. J . , and D. H. Elliot. 1972. The early Mesozoic vol-caniclastic Prebble Formation, Beardmore Glacier, Antarctica.In: Antarctic Geology and Geophysics (R. J . Adie, editor). Olso,Universitetsforlaget. 403-409.

Doumani, G. A. 1960. Geological observations in West Antarc-tica during recent oversnow traverses. New York, AmericanGeophysical Union. Transactions, 41: 706-710.

Moore, J . G., and D. L. Peck. 1962. Accretionary lapilli in vol-canic rocks of the western continental United States. Journalof Geology, 70: 182-193.

Ross, C. S. 1941. Origin and geometric form of calcedony-filledspherulites from Oregon. American Mineralogist, 26: 727-732.

Stump, Edmund. 1974. Volcanic rocks of the Early CambrianTaylor Formation, central Transantarctic Mountains. Antarc-tic Journal of the U.S., IX(5): 228-229.

Stump, Edmund. 1976. On the late Precambrian-early Paleozoicmetavolcanic and metasedimentary rocks of the Queen MaudMountains, Antarctica, and a comparison with rocks of similarage from southern Africa. Columbus, The Ohio State Uni-versity, Institute of Polar Studies. Report, 62.

Wade, F. A. 1974. Geological surveys of Marie Byrd Land andthe central Queen Maud Range. Antarctic Journal of the U.S.,IX(5): 241-242.

Wade, F. A., V. L. Yeats, J . R. Everett, D. W. Greenlee, K. E.LaPrade, and J . C. Shenk. 1965. The geology of the centralQueen Maud Range, Transantarctic Mountains, Antarctica.Antarctic Research Report Series, 65-1. Lubbock, Texas Tech-nological College. 54p.

Weathering and mineral synthesisin antarctic soils

F. C. UG0LINICollege of Forest ResourcesUniversity of Washington

Seattle, Washington 98195

In the polar regions emphasis has been placed onthe prevalence of physical versus chemical weather-ing, and in Antarctica the results of a study of Kellyand Zumberge (1961) would seem to preclude anypossibility of chemical weathering of significancetoday. Other studies conducted in the Mirnyy oasisand in the ice-free areas of southern Victoria Landadvanced evidence that mineral alteration is pres-ently occurring (Glazovskaia, 1958; Ugolini, 1964;Claridge, 1965; Linkletter, 1971; Behling, 1971;Bardin and Konopleva, 1975). Direct evidence of(1) ionic migration and (2) a continuous unfrozenfilm of water at the surface of the soil particles inthe frozen antarctic soils support the possibility ofcontemporary chemical weathering (Ugolini and

Grier, 1969; Ugolini and Anderson, 1973). Pre-vious studies in southern Victoria Land (Ugoliniand Bull 1965; Linkletter, 1971; Behling, 1971;Ugolini et al., 1973) have shown that silt and claypercentages increase from younger to older soils.These results apparently indicate that weatheringis occurring and that there is a weathering-timerelationship. These findings suggest two possiblemechanisms for the formation of clay: (1) synthesisof new minerals and/or (2) comminution or fractur-ing of existing minerals. To establish whether theincrease of silt and clay is due to either synthesesof clay minerals or to comminution or both, threesoils from Wright Valley, southern Victoria Land,were selected: one relatively young, one of inter-mediate age, and one old. The particle-size analy-sis performed on these samples emphasizes theimportance of the parent material on the mechani-cal constituents of soils. The old soil derived fromgranitic bedrock has almost as much clay as theintermediate soil formed on the moraine where theglacier had provided the initial grinding of theminerals. The young soil, however, despite deriva-tion from glacial deposits, has the lowest clay con-tent. Free-iron oxides, extracted either with oxalate(Fe.) or with dithionate (Fed), are used as indices ofchemical weathering. The Fe O/Fed ratio is related tothe degree of crystallinity of the iron oxides lib-erated through weathering. The lowest ratio re-corded in the old soil indicates a high degree ofcrystallinity, long exposure, and high intensity ofweathering. Thin sections of selected rock frag-ments at different depths from the old soil showthat feldspar is altering to mica and that the de-gree of weathering increases toward the surface.The best documented case of in situ clay synthesiswas found in the old profile (Jackson et al., in press).Here the feldspar in the granitic rock was weath-ered, in the soil, into a clay mica that, in turn, wasweathered into montmorillonite that subsequentlywas interlayered with iron, forming chloritizedmontmorillonite. The mineralogy of the young pro-file shows that the feldspar amount decreases withparticle size but still persists in the fine clay. Themajor minerals in this fraction include montmoril-lonite and mica vermiculite intergrade. Bothminerals are considered to be authigenic. In theintermediate profile, montmorillonite and mica-vermiculite intergrade occur in the coarse clay frac-tion; both minerals are considered to be authigenic.In this profile the prevailing minerals in the fineclay fraction are mica- vermiculite intergrades;whereas a vermiculite- montmorillonite intergradeis the major constituent of the coarse clay fraction.Both mineral assemblages are considered to beauthigenic.

Although not fully documented, the weatheringsequence in the young and intermediate soils seems

248 ANTARCTIC JOURNAL

to indicate that the feldspar is weathering to mica,the mica into vermiculite, and vermiculite intomontmorillonite. The best documentation for thesynthesis of new minerals in Antarctica was ob-tained from the old soil where the fission track ageof the soil mica indicates an age of 4.1 ±0.2 millionyears in contrast to an age of 151 million years forthe parent rock mica (Jackson et al., in press). Thepreliminary conclusion of this study is that mineralsynthesis is occurring in Antarctica; however,additional dating by the fission-track method isneeded for ascertaining whether the mica is detritalor authigenic in the young and intermediate soils.

This research was supported by National ScienceFoundation grant DPP 74-20701.

References

Bardin, V. I., and V. I. Konopleva. 1975. On the weatheringprocesses and the problem of geochronology of the glacialperiod of Antarctica. In: The Antarctic Committee Reports, 1969(V. A. Bugaev, editor). New Delhi, Amerind. 130-142.

Behling, R. E. 1971. Pedological development on moraines ofthe Meserve Glacier, Antarctica. Ph.D. thesis. Columbus, TheOhio State University. 216p.

Claridge, C. C. 1965. The clay mineralogy and chemistry ofsome soils from the Ross Dependency, Antarctica. N.Z. Jour-nal of Geology and Geophysics, 8: 186-220.

Glazovskaia, M. A. (Glazovskaya). 1958. Weathering and pri-mary soil formation in Antarctica. Navc. DokI. Vyss. Skol. geol.-geogr. Nauk, 1: 63-76.

Jackson, M. L., S. Y. Lee, F. C. Ugolini, and P. A. Helmke. Inpress. Age and uranium content of antarctic soil micas by thefission particle track method. Soil science, 121.

Kelly, W. C., and J. H. Zumberge. 1961. Weathering of quartzdiorite at Marble Point, McMurdo Sound, Antarctica. journalof Geology, 69: 433-446.

Linkletter, G. 0. 1971. Weathering and soil formation in Ant-arctica dry valleys. Ph.D. thesis. Seattle, University of Wash-ington. 122p.

Ugolini, F. C. 1964. A study of pedologic processes in Antarc-tica. Final report to NSF. New Brunswick, New Jersey, Rutgers.82p.

Ugolini, F. C., and D. M. Anderson. 1973. Ionic migration andweathering in frozen antarctic soils. Soil Science, 115: 461-470.

Ugolini, F. C., J . C. Bockheim, and D. M. Anderson. 1973. Soildevelopment and patterned ground evolution in Beacon Val-ley, Antarctica. In: Permafrost: The North American Contributionto the Second International Conference. Washington, D.C., Na-tional Academy of Sciences. 783p.

Ugolini. F. C., and C. Bull. 1965. Soil development and glacialevents in Antarctica. Quaternaria, 7: 251-269.

Ugolini, F. C., and C. C. Grier. 1969. Biological weathering inAntarctica. Antarctic Journal of the U.S., IV(4): 156-157.

Examining antarctic soils with ascanning electron microscope

MoTo! KUMAI, D. M. ANDERSON,' andF. C. UG0LINI2

U.S. Army Cold Regions Research and EngineeringLaboratory

Hanover, New Hampshire 03755

Jones et al., (1973) report a study of volcanic ashfrom Antarctica by scanning electron microscopy(5EM) and by electron microprobe. The volcanicashes examined were collected at two sites nearLake Vanda in the upper Wright Valley. They con-sisted of amorphous, porous, friable, light-grayvolcanic materials. Their amorphous nature wasconfirmed by a powder X-ray diffraction analysisthat indicated an absence of crystallinity.

Here we present the results of an investigation,by SEM and energy dispersion X-ray analysis, of themorphology, degree of weathering, and chemicalspecies for six samples of recent moraines and de-composed sandstones from Antarctica (figure 1).

Energy dispersion X-ray analysis (EDxA). Eighteencommon elements (sodium, magnesium, alumi-num, silicon, phosphorus, sulfur, chlorine, potas-sium, calcium, titanium, chromium, manganese,iron, cobalt, nickel, copper, palladium, and gold)were identified easily by EDXA. The acceleratingvoltage was 20 kilovolts. Eleven elements (sodium,magnesium, aluminum, silicon, sulfur, chlorine,potassium, calcium, titanium, manganese, andiron) were determined to be in the soil samples.Chromium, palladium, and gold (used in shadow-ing) also were found. Phosphorus, cobalt, andnickel were not observed.

EDXA was carried out for standard clay mineralssuch as dickite 15c and montmorillonite 23. Thelimit of detectability was determined using stan-dard clay minerals and was found to be about 0.1percent for sodium and potassium, and 0.01 per-cent for iron.

Quantitative analysis for soil samples 2 and 3from a recent moraine in lower Wright Valley was

'Now at the National Science Foundation, Washington, D.C.20550.

'College of Forest Resources, University of Washington,Seattle, Washington 98105.

December 1976 249