ERSC 1F90 Lecture Notes - Lecture 6: Viscosity, Beringia, East Antarctic Ice Sheet
26 Feb 2016
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Document Summary
Most of the ice volume is in the eais (east antarctic ice sheet); the wais is smaller. Most of the quaternary increase in ice cover was in the northern hemisphere in the circum- north atlantic. Sea level measurements from preserved coastal features, such as uplifted or drowned beach terraces, coral reefs, caves (blue hole) Pleistocene megafauna abounded on the exposed land area, as in beringia above the tundra exposed between alaska and siberia by sea level lowering at the lgm. For glaciers to originate more snow has to fall than melts during the following warmer interval (positive mass balance) Snow is metamorphosed to glacial ice whenever accumulation exceeds ablation (i. e. positive mass balance) Ice is always moving in a glacier due to gravity; ice flow is plastic at depth, but the surface can be intensely fractured. Ice flow is usually imperceptible, but sometimes glaciers surge.
