COMMUNITY STRUCTURE AND POPULATION DYNAMICS OF PLEISTOCENE BENTHIC FORAMINIFERA FROM ODP SITE 1171C (SOUTH TASMAN RISE)

Ocean Drilling Program (ODP) Leg 189 examined the Cretaceous to Holocene geologic and paleoceanographic history of the Tasmanian Gateway. As a result of this expedition, sediments were recovered from Site 1171 Hole C located on the South Tasman Rise, south of Tasmania. This study focuses on the Pleistocene sediments (light gray foraminiferal nannofossil ooze and foraminifer-bearing nannofossil ooze). This study investigates the population of Pleistocene benthic foraminifera at ODP Site 1171C. Our goal is to analyze the community structure to tie these fossils to an oceanographic setting.

Six 20 cc sediment samples spaced at approximately 20,000-year intervals were obtained from the Gulf Coast Repository for the purpose of this study. Each sample was washed and sieved to separate it into size fractions (63-125 microns and >125 microns). The > 125-micron samples have been picked to analyze the benthic foraminiferal population. While planktonic foraminifera are dominant, we hope to have enough benthic foraminifera to present a preliminary analysis of the community (presence/absence data, diversity, etc.). The micropaleontological data will be compared to geochemical data collected by the Shipboard Scientific Party (2001) to try to further reconstruct the paleoceanography of the setting.