PARAGLACIAL REDISTRIBUTION OF GLACIAL SEDIMENTS IN THE VESTFOLD HILLS, EAST ANTARCTICA

The Vestfold Hills landscape is dominated by bare-rock slopes and unco nsolidated deposits form a minor component of the surficial geology. T he principal objectives of the study were to explain the distribution of unconsolidated deposits, determine the nature and timing of sedimen tary processes during and after deglaciation, and the impact of these processes on landscape development. Observations of late Quaternary gl aciation and deglaciation of the area and contemporary depositional pr ocesses are reported, and a conceptual model of geomorphological chang e since deglaciation is presented. The model attempts to reconcile the types and rates of contemporary depositional processes with the distr ibution of deposits and landforms, and to explain why unconsolidated d eposits cover less than 20% of the Hills despite the effects of recent glaciation, The lack of unconsolidated deposits in the landscape can be attributed to the combined effects of low debris volumes in the ice and the redistribution of debris during and after deglaciation. Redis tribution of debris can be explained by paraglacial processes which ar e non-glacial sedimentary processes that are directly conditioned by g laciation. Paraglacial sedimentation is a response to rapid adjustment of the debris system after the dominance of glacial conditions, and i s characterized by disequilibrium between sediment supply and transpor tation of sediment by nonglacial processes. Evidence from the Vestfold Hills suggests paraglacial sedimentary processes are dominated by mas s movement of glacial debris from slopes and the formation of stable v alley fills, and that the main sediment transfers occur within a few t housand years of deglaciation.