HR: 0800h
AN: PP51A-0197    [Abstracts]
TI: Foraminiferal Record from Firth of Tay, West Antarctica
AU: * Majewski, W
EM: wmaj@twarda.pan.pl
AF: Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, Warszawa, 00-818, Poland
AB: The Firth of Tay is a small embayment between Joinville and Dundee Islands at the north-east tip of Antarctic Peninsula. This site was sampled during two SHALDRIL operations in 2006 and 2007. A 75 m long, composite, Holocene section was recovered from ~630 m water depth. It has the potential to reveal the best, expanded record of climatic and oceanographic changes on the east side of the Antarctic Peninsula. Foraminiferal investigation of the lower portion of this section (core NBP0602A-8B-KC) is in progress. The first results indicate significant variations in faunal abundances and population structure throughout. They are due to environmental fluctuations affecting the foraminiferal communities and diagenetic processes that took place after deposition. Some diagenetic gypsum was found abundant ~33 mbsf. Between 42 and 54 mbsf some layers rich in organic detritus (plant or shell fragments) were encountered. The calcareous benthic foraminifera are dominated by Globocassidulina biora accompanied by Fursenkoina fusiformis, few Nonionella and Cibicides, while the agglutinated assemblage by Miliammina arenacea, Paratrochammina bartmani, and Portatrochammina. Down to ~33 mbsf, some more fragile Spiroplectammina were also encountered. All these foraminiferal taxa are typical for Recent environments of similar water-depths in the area. The percent of calcareous foraminifera is low (0-20%) and variable between 9 and 42 mbsf, and it is significantly higher (up to ~95%) towards greater core depths. The most diverse, abundant, and best preserved assemblages were encountered near the bottom of the section below 70 mbsf. They are strongly dominated by various calcareous foraminifera typical for open-marine shelf-waters. In the deepest samples, few planktonic Neogloboquadrina pachyderma were also found supporting the most open-water conditions during deposition of the lowest part of the section. Around 54 mbsf, especially abundant benthic foraminiferal assemblages were noted. However, they are suspected to represent mixed populations.
DE: 0459 Macro- and micropaleontology (3030, 4944)
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4944 Micropaleontology (0459, 3030)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting