The discovery Tablemount chain

A high carbonate ooze core of Lower Pleistocene age from the Discovery Tablemount contains planktonic foraminifera, coccoliths, ice-rafted detritus and little clay. Thin-shelled planktonic foraminifera indicate a shoaling to 200 m during the Lower Pleistocene. Changes in the foraminiferal population indicate two cold episodes during which the Antarctic Convergence was considerably further north than at present. An abundance of ice-rafted quartz sand grains coincides with the latter part of a warm period; the grains are ice and wind erosion products of exposed Antarctic rocks. Dredged volcanic rocks indicate volcanism occurred on the tablemount at 25 m.y. BP (K/Ar) and 6.5 to 7 m.y. BP(induration of ooze).