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Silica deposits on Mars could entomb possible life

Deposits of hydrated silica on a Martian volcano point to a hydrothermal origin - they could preserve evidence of ancient life

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THE pale deposits on the flank of an ancient volcano on Mars don’t look like anything special. But they might be the Red Planet’s answer to amber, trapping and preserving any life that was present at the site billions of years ago.

Measurements by a spectrometer on NASA’s Mars Reconnaissance Orbiter indicate that the deposits contain hydrated silica, a mineral that can be concentrated by the action of hot water or steam. This suggests that the deposits were laid down by hydrothermal processes (Nature Geoscience, ).

“The heat and water required to create this deposit probably made this a habitable zone,” says John Skok of Brown University in Providence, Rhode Island, who led the team that identified the mineral.

The deposits could have preserved evidence of any life that may have existed when they formed about 3.7 billion years ago. “Silica is a nice little coffin-making device,” says team member John Mustard, also at Brown University. “As it precipitates out, it coats things. If there was biological material, it could be wrapped up in a silica coating, like a jelly bean.”

In 2007 NASA’s Spirit rover also found hydrated silica, beneath the soil in a region thought to have been volcanic, but its origin was uncertain. Mustard says the fact that the newly observed deposits lie on the side of a volcano leave no doubt as to their origin.