Neogene diatom biostratigraphy of ODP Leg 113

Diatom assemblages recovered during ODP Leg 113 at eight sites in the Weddell Sea (Atlantic sector of the circum-Antarctic Ocean) provide new insights into southern high-latitude Neogene diatom biostratigraphy. The excellent sections recovered by ODP Leg 113 Sites 689 and 690 (Maud Rise, southeast Weddell Sea, Antarctic Ocean) were chosen for the establishment of a revised Neogene Antarctic diatom zonation. Altogether, 16 diatom zones are described as well as several stratigraphically useful diatom datums of late early Miocene to Pleistocene age. Six zones established by previous authors are partly modified or renamed, and 10 new zones are proposed. The zones are calibrated directly to the geomagnetic time scale, which provides a chronological framework for the zones and permits comparisons of Neogene Antarctic diatom events with events described from the low and northern high latitudes. This is the first attempt at direct calibration of Miocene Antarctic diatom zones with the geomagnetic time scale.