Glaciomarine sediment drifts from Gerlache Strait,Antarctic Peninsula

摘要

Four sediment cores were collected along the Gerlache Strait, Western Antarctic Peninsula, overtwo extremely thick, sedimentary accumulations: the Andvord and the Schollaert drifts. The fourcores present a sediment facies succession from couplets of laminated diatom ooze and sandy-mud 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 structuredefined by wavy stratified reflectors onlapping the northern slope of the strait. We suggest that theformation of the Schollaert Drift was strongly related to the persistence of estuarine conditionsduring the Middle Holocene along the Gerlache Strait, arising from blockage of the southern entranceby increased glaciation. Such a blockage would have resulted in a retention of fresh water input frommelting ice margins and melting sea ice, increased surface temperatures, and reduced exchangewith waters originating from the Antarctic Circumpolar Current. In that context, the increase insuspended sediment would have been redistributed by tidal currents leading to enhanced depositionof sediment across the Schollaert Drift.