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Student Research: Ancient Snowfall Likely Carved Martian Valleys

September 11, 2013
Mars from the Odyssey spacecraft

Water-carved valleys on Mars appear to have been caused by runoff from precipitation, likely meltwater from snow. Early Martian precipitation would have fallen on mountainsides and crater rims. Credit: Images from NASA

Researchers at Brown University, including Kat Scanlon, a geological sciences graduate student, have shown that some Martian valleys appear to have been caused by runoff from orographic precipitation — moisture carried part of the way up a mountain and deposited on the slopes.

Valley networks branching across the Martian surface leave little doubt that water once flowed on the Red Planet. But where that ancient water came from — whether it bubbled up from underground or fell as rain or snow — is still debated by scientists. A new study puts a new check mark in the precipitation column.

The study finds that water-carved valleys at four different locations on Mars appear to have been caused by runoff from orographic precipitation — snow or rain that falls when moist prevailing winds are pushed upward by mountain ridges. The new findings are the most detailed evidence yet of an orographic effect on ancient Mars and could shed new light on the planet’s early climate and atmosphere.

Read more of Kevin Stacey's article about snow on Mars.