Late Cretaceous through Neogene deep-sea benthic foraminifers (Maud Rise, Weddell Sea, Antarctica)

Abstract

Upper abyssal to lower bathyal benthic foraminifers from ODP Sites 689 and 690 on Maud Rise are reliable indicators of Maestrichtian through Neogene changes in the deep-water characteristics at high southern latitudes. Benthic foraminiferal faunas were divided into eight assemblages, with periods of faunal change at the early/late Maestrichtian boundary (69Ma), at the early/late Paleocene boundary (62Ma), in the latest Paleocene (57.5Ma), in the middle early Eocene to late early Eocene (55-52Ma), in the middle middle Eocene (46Ma), in the late Eocene (38.5Ma), and in the middle-late Miocene (14.9-11.5Ma). The highest diversities of the post-Paleocene occurred during the middle Eocene; from that time on the diversity decreased steadily at both sites. Data on faunal composition suggest that the waters bathing Maud Rise were well ventilated during the Maestrichtian through early Paleocene as well as during the latest Eocene through Recent. The waters appeared to be less well ventilated during the late Paleocene as well as the late middle through early late Eocene, with the least degree of ventilation during the latest Paleocene through early Eocene. -from Author