Glaciomarine sedimentation on the continental rise from the Bellingshausen Sea, West Antarctica

Abstract

The effects of glaciomarine sedimentary processes are recognised from variation of sedimentary facies in two deep sea cores taken from the continental rise of the western Antarctic Peninsula. Two sediment cores (one gravity core and one piston core) were visually described, logged for magnetic susceptibility, and X-radiographed. Their analyses were performed for grain size, geochemistry, and clay minerals. Three sediment types associated with distinct sedimentary processes of last glacial, deglaciation and Holocene are recognized: (1) Terrigenous mud of glacial sediment accumulated from a combination of sedimentary processes including contour/turbidity currents and turbid plumes, (2) slightly bioturbated silt mud derived from meltwater discharges, and (3) hemipelagic mud of interglacial sediment accumulated from the pelagic settling of bioclasts and ice-rafted/wind-transported detritus. Two depositional settings are interpreted within sediment drift 1 (side of the drift) and sediment drift 3 (top of the upper rise), each characterized by the dominance/interaction of one or several depositional processes.