जल विज्ञान: वर्तमान अनुसंधान

The Generation of Mega Glacial Meltwater Floods and Their Geologic Impact

Abstract

Paul A LaViolette

A mechanism is presented explaining how mega meltwater avalanches could be generated on the surface of a continental ice sheet. It is shown that during periods of excessive climatic warmth when the continental ice sheet surface was melting at an accelerated rate, self-amplifying, translating waves of glacial meltwater emerge as a distinct mechanism of meltwater transport. It is shown that such glacier waves would have been capable of attaining kinetic energies per kilometer of wave front equivalent to 12 million tons of TNT, to have achieved heights of 100 to 300 meters, and forward velocities as great as 900 km/hr. Glacier waves would not have been restricted to a particular locale, but could have been produced wherever continental ice sheets were present. Catastrophic floods produced by waves of such size and kinetic energy would be able to account for the character of the permafrost deposits found in Alaska and Siberia, flood features and numerous drumlin field formations seen in North America, and many of the lignite deposits found in Europe, Siberia, and North America. They also could account for how continental debris was transported thousands of kilometers into the mid North Atlantic to form Heinrich layers. It is proposed that such layers’ form at times when a North Atlantic sea ice shelf borders the ice sheet and when climate warms abruptly producing accelerated meltwater discharge.