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Paper No. 33
Presentation Time: 9:00 AM-6:30 PM

MICRO- AND MACROFOSSILS FROM TERRACE DEPOSITS, TAYLOR VALLEY, ANTARCTICA


KLING, Corbin L.1, WALKER, Sally E.1 and BOWSER, Samuel S.2, (1)Department of Geology, University of Georgia, Athens, GA 30602, (2)Wadsworth Center, New York State Department of Health, Albany, NY 12201, corbayn@uga.edu

The provenance of fossils located on the coastal margins of the Taylor Valley, Antarctica, are thought to stem from marine terraces generated by glacial retreat although it is possible that some of the fossils could result from sea-ice transport. To understand how sea ice could have contributed hardparts to the Taylor Formation, sediment samples (delimited to 10 ml) from uplifted marine terrace and sea-ice deposits were compared on the basis of fossil diversity, relative abundance and taphonomic (preservational) condition. Taphonomic condition of the most common hardparts (i.e., foraminifera) was assessed using a ranking system: 0, pristine condition; 1, 1-24% slight dissolution/abrasion; 2, 25-49% moderate dissolution/abrasion; 3, 50-74% dissolution/abrasion, and 4, 75% or greater dissolution/abrasion. The average taphonomic rank was used to compare among samples.

Results indicate that sea-ice and fossil deposits contained foraminifera, echinoderm spines and sponge spicules; ostracodes were present in sea-ice samples. Abundance of foraminifera varied widely in terrace samples, ranging from 98 to 4 individuals, while sponge spicules and echinoderm spines were relatively rare in all samples. Ostracodes were common in sea-ice samples. Both sea-ice and fossil samples contained either mostly calcareous or mostly agglutinated foraminifera. Taphonomic ranking for terrace deposits was 2.12, while sea-ice samples ranked 2.57, indicating slightly more abrasion and dissolution in the sea-ice samples. Overall, the fossil and sea-ice samples were very similar, which is not surprising as portions of the seafloor are uplifted by anchor ice and welded to the bottom of sea ice, and through ablation and sublimation, the formerly benthic samples are exposed to the surface. While more sediment samples are being processed, is is quite possible that both sea-ice and uplifted terrace deposits can both contributed to the fossil record in the dry valleys of Antarctica.

Session No. 127--Booth# 114

Paleontological Discoveries and Biostratigraphy (Posters)
Monday, 28 October 2013: 9:00 AM-6:30 PM
Hall D (Colorado Convention Center)
Geological Society of America Abstracts with Programs. Vol. 45, No. 7, p.329
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