LOW-RESOLUTION STUDY OF BENTHIC FORAMINIFERA FROM PLEISTOCENE COOL-WATER CARBONATES FROM TASMANIA DURING THE PLEISTOCENE (ODP SITE 1168A)

Benthic foraminifera from sediment samples recovered during Ocean Drilling Program (ODP) Leg 189-The Tasman Gateway were examined to determine how changing Southern Ocean conditions affect populations. All samples come from Site 1168 situated 70 km from the Tasmanian coast on the western continental slope (2463 m below the surface) and are spaced at roughly 150,000 years apart. Identifications of the fauna were done using a dissecting microscope and reference materials. Physical property data from Brughmans (2003), and The Scientific Shipboard Party (2001) were used. In addition, Hughes [unpublished Master’s thesis] benthic foraminiferal data was used to look at the bigger picture of Pleistocene seafloor conditions at that location.

Within the data, large-scale changes correlating with glacial and interglacial periods can be seen in the changing benthic foraminiferal population and varying physical properties measured in samples. The Subtropical Convergence, a surface oceanic front, likely moved as conditions changed from glacial to interglacial period. Also evident within these samples is the mid-Pleistocene extinction event affecting some benthic foraminiferal families (Stilostomellidae and Pleurostomellidae) during the mid-Pleistocene climate transition.