The Antarctic glacial history recorded in sediments of the Southern Ocean

Abstract

A study of the distribution of sediment types and of ice rafted glacial debris in marine cores from the Southern Ocean provides an outline of Late Tertiary Antarctic glaciation, while the paleomagnetic dating of these cores has established its chronology. The results suggest a glacial maximum during the Gauss paleomagnetic epoch (2.35–3.35 m.y.) during which the 0° surface water isotherm was displaced northwards more than 5° of latitude relative to the present. Glaciation waned sporadically during the Matuyama epoch (0.7–2.35 m.y.) to reach its present extent during the Bunhes epoch (0.–0.7 m.y.). Although the southern limit of permanent sea ice has been poleward of its present limit in the Pacific and Weddell Seas during the past 0.7 m.y., the position of the convergence has not been shifted much south of its present position during this time. Antarctic glaciation was initiated prior to 5.0 m.y. ago.