Editor's Summary

21 February 2008

Water flow on Mars

Understanding how surface water flow could have produced the observed deltas and alluvial fans on the surface of Mars is fundamental to understanding the history of water on the planet. Flow duration in particular is an important factor, but to date, estimates for the longevity of martian hydrologic events have varied erratically, from decades to millions of years. Now, in a series of experiments here on Earth, in the Eurotank facility at Utrecht University, the characteristic morphology of martian stepped or terraced deltas has been recreated. The findings suggest that the stepped fans were formed by sudden release of water from subsurface storage, rather than by surface precipitation. In the conditions prevailing on Mars, this morphology is consistent with a single basin-filling event taking tens of years, and may have required an amount of water comparable to that discharged by a large terrestrial river about the size of the Mississippi. The cover image is a photo composite of a 4 mm-per-pixel digital terrain model of an experimentally formed crater from the Eurotank.

Letter: Martian stepped-delta formation by rapid water release

Erin R. Kraal, Maurits van Dijk, George Postma & Maarten G. Kleinhans

doi:10.1038/nature06615

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