Glacial Sedimentary Processes and Products

Four sediment cores were collected along the Gerlache Strait, Western Antarctic Peninsula, over two extremely thick, sedimentary accumulations: the Andvord and the Schollaert drifts. The four cores present a sediment facies succession from couplets of laminated diatom ooze and sandymud alternating with massive, bioturbated, terrigenous silt/clay unit to a predominantly massive, bioturbated, silty-clay unit. Seismic profiles across the Schollaert Drift show an internal structure defined by wavy stratified reflectors onlapping the northern slope of the strait. We suggest that the formation of the Schollaert Drift was strongly related to the persistence of estuarine conditions during the Middle Holocene along the Gerlache Strait, arising from blockage of the southern entrance by increased glaciation. Such a blockage would have resulted in a retention of fresh water input from melting ice margins and melting sea ice, increased surface temperatures, and reduced exchange with waters originating from the Antarctic Circumpolar Current. In that context, the increase in suspended sediment would have been redistributed by tidal currents leading to enhanced deposition of sediment across the Schollaert Drift