GLACIMARINE PROCESSES AND INDUCTIVE LITHOFACIES MODELING OF ICE SHELF AND TIDEWATER GLACIER SEDIMENTS BASED ON QUATERNARY EXAMPLES

Three variables control the type of glacial debris source and where and when debris is introduced to an ocean: (1) type of glacial ice source (ice sheet or valley glacier); (2) condition of a ground glacier (melting/freezing or frozen base and cold or warm internal ice); and (3) type of glacier front (ice shelf or tidewater). Using these variables in different combinations eight glacimarine regimes are postulated to exist. By integrating information from Holocene sediment and Pleistocene glacimarine sequences with the eight inductive regimes, lithofacies relationships are predicted and modeled. The models show a complexity of glacimarine lithofacies. The importance of recognizing this complexity lies in realistic interpretations of ancient sequences. Ice shelf sediment may be limited in the geologic record because of tectonic and climatic constraints requeired for ice shelf formation. Alternatively, in some tidewater glacier regimes larger volumes of glacimarine sediment are produced than in ice shelf regimes.