Glacial and Glacial Marine Sediments of the Antarctic Continental Shelf

Abstract

Until recently, contributions towards the understanding of glacial marine sedimentation have been limited. Sedimentologie studies of continental shelf deposits recently cored in the Weddell Sea, Ross Sea, and the George V region of Antarctica have enabled the distinction of three types of sediment. Type 1 sediments are massive, poorly sorted, and texturally and mineralogically homogeneous downcore; they are unfossiliferous or contain reworked fossils, lack a preferred pebble orientation, and are overcompacted. They are interpreted as being basal tills. Type 2 sediments are crudely stratified, contain a sorted mud fraction, are texturally and mineralogically heterogeneous downcore, contain distinctive microfossil assemblages, are typically normally compacted, and have a horizontal pebble fabric. Type 3 sediments are similar to Type 2 sediments except that they are depleted in silt and clay and contain a moderately sorted sand fraction. Both Type 2 and Type 3 sediments are deposited from floating ice and re...