A geological and geophysical investigation of sedimentation and recent glacial history in the Gerlache Strait region, Graham Land, Antarctica

Abstract

Piston cores, bottom grabs, and single-channel seismic data acquired during Deep Freeze/USARP cruises have been used to examine sedimentation and recent climatic history in the bays and fjords of the Gerlache Strait region (Antarctic Pensinsula). The local climate and glacial setting exhibit profound influences on sedimentation via the processes associated with subglacial water. Visible sediment plumes are rare, and glacial ice above sea level is pristine white, indicating that debris is entering the water from the glaciers that are grounded below sea level. In the relatively warm and wet Palmer Archipelago, terrigenous muds and sands with a variable IRD component are ponding in every available bathymetric depression, and sediment gravity flow processes are common. Along the colder and drier Danco Coast, diatomaceous sediments drape uniformly across the rugged basement topography, rather than ponding, and resedimentation is rare. In both areas, sedimentation occurs in quiescent water.