Paraglacial redistribution of glacial sediments in the Vestfold Hills, East Antarctica

The Vestfold Hills landscape is dominated by bare-rock slopes and unconsolidated deposits form a minor component of the surficial geology. The principal objectives of the study were to explain the distribution of unconsolidated deposits, determine the nature and timing of sedimentary processes during and after deglaciation, and the impact of these processes on landscape development. Observations of late Quaternary glaciation and deglaciation of the area and contemporary depositional processes are reported, and a conceptual model of geomorphological change since deglaciation is presented. The model attempts to reconcile the types and rates of contemporary depositional processes with the distribution of deposits and landforms, and to explain why unconsolidated deposits cover less than 20% of the Hills despite the effects of recent glaciation. The lack of unconsolidated deposit 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. Redistribution of debris can be explained by paraglacial processes which are non-glacial sedimentary processes that are directly conditioned by glaciation. Paraglacial sedimentation is a response to rapid adjustment of the debris system after the dominance of glacial conditions, and is characterized by disequilibrium between sediment supply and transportation of sediment by nonglacial processes. Evidence from the Vestfold Hills suggests paraglacial sedimentary processes are dominated by mass movement of glacial debris from slopes and the formation of stable valley fills, and that the main sediment transfers occur within a few thousand years of deglaciation.