Middle Eocene to Pleistocene calcareous nannofossils recovered by Ocean Drilling Program Leg 113 in the Weddell Sea

Abstract

ODP Sites 692 and 693 on the Weddell Sea margin of East Antarctica and Site 696 on the South Orkney microcontinent of West Antarctica yielded calcareous nannofossils within some stratigraphic intervals. Calcareous nannofossil biostratigraphy suggests a major haitus across the Paleogene/Neogene boundary at Sites 689 and 690, and two additional hiatuses in the Middle Eocene-Lower Oligocene section at Site 690. Correlation with magnetostratigraphy was attempted. Calcareous nannofossil assemblages indicate that by at least the Middle Eocene, surface water temperatures became considerably lower in the high southern latitudes than in the middle-latitude areas and that there have been more extreme cold events in the high latitudes during the Neogene. Bicolumnus ovatus n.gen., n.sp. is proposed in this paper. -from Authors