Megafloods on Earth and Mars

Vic Baker

(Department of Hydrology and Water Resources and Lunar and Planetary Laboratory, University of Arizona)

After centuries of geological controversy it is now well-established that the last major deglaciation of planet Earth, about 16,000 years ago, involved huge fluxes of water from the wasting continental ice sheets, and that much of this water was delivered as floods of immense magnitude and relatively short duration. These late Quaternary megafloods, and the megafloods of earlier glaciations, had short-term peak flows, comparable in discharge to the more prolonged fluxes of ocean currents. (The discharges for both ocean currents and megafloods generally exceed one million cubic meters per second, hence the prefix "mega".) Some outburst floods likely induced very rapid, short-term effects on Quaternary climates. The late Quaternary megafloods also greatly altered drainage evolution and the planetary patterns of water and sediment movement to the oceans. Even larger megafloods are inferred to have occurred on Mars. As on Earth, the Martian megafloods probably exerted a profound influence on climate change. The Martian megafloods are intimately tied to the hydrogeological evolution of that planet in ways that have yet fully to be discerned.

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