LATE QUATERNARY SEDIMENT FACIES IN PRYDZ-BAY, EAST ANTARCTICA AND THEIR RELATIONSHIP TO GLACIAL ADVANCE ONTO THE CONTINENTAL-SHELF

A marine survey in Prydz Bay, provides an unparalleled view of glacige nic and marine sedimentation across Prydz Channel and Amery Depression during the Late Quaternary. Gravity cores and a suite of eight radioc arbon dates indicate that the Late Wisconsin Glacial Maximum (LGM) was associated with grounding of a palaeo-ice shelf along the periphery o f Prydz Channel. Deposition in front of the grounding line was dominat ed by ice-rafting. A granulated facies, containing angular clay and di amicton clasts, was produced by a combination of regelation freezing, near to the grounding line, and remelting of this basal debris in the sub-ice shelf setting. Beneath these LGM marine deposits lie two key b eds of diatom ooze that are distinct in size sorting and Pliocene diat oms. These ''interstadial'' units can be traced across most of the Pry dz Channel, and are underlain by additional glacial marine units. Debr is related to the Lambert Deep is distinct from detritus from eastern Prydz Bay and deposition of these two sources within the channel oscil lated during the LGM. We suggest that coastal drainage systems contrib uted to a limited glaciation of the shelf during the LGM, rather than direct outflow via the Lambert/Amery system. it is proposed that shelf -wide glaciation is related to the duration of glacial sea level lowst ands rather than the absolute magnitude of eustatic fall during such e pisodes.