Sedimentological signatures of sub-ice-shelf circulation: An example from Vincennes Bay, East Antarctica

Abstract

Two cores of Holocene sediment, collected on opposite flanks of the Vanderford Glacier in Vincennes Bay, while representing contemporaneous sedimentation, have different sediment characteristics, with a relatively lower biogenic content on the western side than on the east. These sedimentological signatures are attributed to differences in circulation patterns. Circulation involves landward flow at depth, bringing warmer ocean water into contact with the base of the glacier. This water becomes mixed with fresh meltwater and suspended glacial sediments to form a buoyant plume that rises and flows in a seaward direction under the ice shelf. The landward and seaward flows are deflected to the left in the Southern Hemisphere by the Coriolis effect and, hence, are laterally separated. This pattern explains the differences observed in sediments deposited on opposite sides of the ice shelf in front of the Vanderford Glacier and may be a common feature beneath all large-scale ice shelves.