Hundreds of Salt Deposits Spotted on Mars

March 20, 2008

Evidence of a dense brine that once oozed on Mars could bring new vigor to the search for salt-loving life-forms on the red planet.

Mikki Osterloo of the University of Hawaii and colleagues have discovered hundreds of small depressions that appear to be filled with the kinds of salt deposits that form on Earth when water evaporates.

The find gives more credence to theories of a wet Martian past—and it confirms the presence of chloride minerals on Mars, which some researchers have suspected for years but only now have the tools to find.

"I think the most exciting aspect of the results of this initial study is that we are continuing to discover new materials on the Martian surface," Osterloo said.

And that opens doors in the search for life uniquely adapted to Mars.

Osterloo's team presents its findings in this week's issue of the journal Science.

Dotting the Surface

The research team found the chloride deposits by studying images taken in 2001 by the Mars Odyssey Thermal Emission Imaging System (THEMIS), as well as supporting data from the Mars Global Surveyor and the Mars Reconnaissance Orbiter.

These spacecraft are sending back the highest-resolution data yet from Mars, and scientists have been improving their techniques for teasing out subtle differences in surface composition from these images.

(See the first hi-res color images of Mars taken by the Mars Reconnaissance Orbiter.)

So far the team has found about 200 deposits, all of which are smaller than 10 square miles (26 square kilometers). The features appear to be widespread across the Martian globe.

The minerals show up most often in regions that formed about 3.8 billion years ago, though some apparently formed a few hundred thousand years later.

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