Glacial-Marine Sediments of West Antarctica and Puget Sound: ABSTRACT

ABSTRACT The ice-covered parts of the world oceans are among the most complex and poorly understood sedimentary environments. Studies of sediments from the Antarctic continental margin and the Pleistocene glacial-marine deposits of the Puget Lowlands are under way, and models for glacial-marine deposition are being developed. These depositional models account for the interrelations among glacial, climatic, oceanographic, isostatic, and sedimentary processes. In particular, glacio-isostatic adjustment and subglacial processes appear to have pronounced effects on sedimentation. Several cruises to the Antarctic continental margin have been conducted and most of the West Antarctic margin has been surveyed. Piston cores from the West Antarctic margin contain a variety of sediment types ranging from nonstratified, nonsorted marine tills to well-sorted, quartz-rich sands and laminated silts. Debris flows, turbidites, biogenic oozes, and other marine sediments are interbedded with glaciogenic deposits. Lateral and vertical variability of sediments and faunas, well-illustrated by stratigraphic sections from the Puget Sound region, suggests that major shifts in depositional boundaries and environments occur frequently. Understanding the complexities of the glacial-marine environment is essential for reconstructing past glacial histories. The origin of glacial-marine sediments cannot be understood by considering processes unique to the marine or glacial environments, but must be evaluated in terms of interactions between the two.