Central Transantarctic Mountains Nonmarine Seposits

  1. Mort D. Turner and
  2. John E. Splettstoesser
  1. Paul Tasch1 and
  2. Edward Leighman Gafford Jr.2

Published Online: 16 MAR 2013

DOI: 10.1029/AR036p0075

Geology of the Central Transantarctic Mountains

Geology of the Central Transantarctic Mountains

How to Cite

Tasch, P. and Leighman Gafford, E. (1986) Central Transantarctic Mountains Nonmarine Seposits, in Geology of the Central Transantarctic Mountains (eds M. D. Turner and J. E. Splettstoesser), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR036p0075

Author Information

  1. 1

    Department of Geology, Wichita State University, Wichita, Kansas 67208

  2. 2

    Battelle, Pacific Northwest Laboratories, Richland, Washington 99352

Publication History

  1. Published Online: 16 MAR 2013
  2. Published Print: 1 JAN 1986

ISBN Information

Print ISBN: 9780875901848

Online ISBN: 9781118664797

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Keywords:

  • Biostratigraphy;
  • Conchostracans;
  • Lithology and mineralogy;
  • Paleolimnology and geochronology;
  • Paleosalinity and ecosystem;
  • Sedimentary phosphate method (SPM);
  • Storm Peak;
  • Trace fossils

Summary

For section 1, Jurassic non-marine deposits occur in the interbeds of successive diabase flows at Storm Peak, Blizzard Heights, and Mauger Nunatak, Antarctica. Biotic elements from measured sections of these interbeds were found to consist of logs, plant debris, sparse algal mats, and a rare charophyte; arthropods (crustacean conchostracans and ostracodes, as well as insects); and fish and spoor. Variations and characteristics of the respective nonmarine ecosystems indicated by the biotic elements include (1) dominance of conchostracans, which were repeatedly the only component; (2) several distinct species of conchostracan genera Cyzicus and Paleolimnadia, which were distributed at different sites in the Beardmore Glacier region and vertically (through time) in the interbed at a given site; (3) biotic components (fishes, insects, crustaceans, and elements of the flora) that appeared seasonally while one or more components of the biota were absent for multiple seasons after which they reappeared. To account for the regional distribution of actinopterygian fishes, seasonal appearances, and absences of other parts of the biota in a given lake, a stream drainage system that connected the several Jurassic lakes is postulated. For section 2, at Storm Peak, paleosalinity (which indicates fluctuations in, but not actual salinity) was determined for the lower and upper basalt flow interbeds (LFI, UFI) by two methods: geochemical partition of boron/gallium and boron/vanadium and by the sedimentary phosphate method. These readings were checked by faunal data. An increase of 3.0 parts per thousand (ppt) through time, was recorded for the LFI, and a decrease of 10 ppt was recorded for the UFI. The Blizzard Heights interbed and its fossil conchostracan fauna that recurred vertically was adequately intact to allow geochronological readings. The year value was 306 ± 20 years. Microprobe analysis of the underlying and overlying basalt flows separated by this time interval detected several differences: The older flow had comparatively much higher chromium (Cr3+) than the younger and the younger flow more SiO2 and MgO than the older flow. Whatever the petrological explanation of such differences, the present report establishes both their occurrence and the time span intervening.