Researchers announced today that they have discovered large salt deposits on the surface of Mars. These deposits point to places where large quantities of water existed on the surface of the Red Planet, perhaps for millions of years. And this might be some of the best places to go looking for evidence of life, past and present.
A team led by Mikki Osterloo at the University of Hawaii, Honolulu have turned up approximately 200 separate spots on southern Mars that seem to have ancient deposits of sodium chloride. In other words, they’ve found table salt sitting on the surface of Mars.
The sites, discovered by NASA’s Mars Odyssey spacecraft, range in size from 1 square km (.6 square miles) to 25 square kms.
So how did this salt get there? One possibility is that it came from groundwater, reaching the surface in low spots. The water would evaporate and leave the mineral deposits over the course of millions of years. Since the sites are largely disconnected from one another, it rules out the possibility the salt was left by an ocean that evaporated billions of years ago.
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“Many of the deposits lie in basins with channels leading into them,” said Philip Christensen, co-author and principal investigator for the camera at Arizona State University. “This is the kind of feature, like salt-pan deposits on Earth, that’s consistent with water flowing in over a long time.”
Don’t go looking for life today, though. The scientists think the salt deposits were formed approximately 3.5 to 3.9 billion years ago. This was a time when Mars had much warmer and wetter conditions than the frigid, dry climate on the planet today.
Until now, researchers have been looking for other evidence of past water on the surface of Mars, like clay or sulfate minerals. Clay is evidence that a region was weathered by water, and sulfates are caused by water evaporation. These salts offer an alternative place to look for evidence of past life.
To get salt deposits of this size, you would need to have large quantities of water sitting on the surface of Mars for a long time. And this is crucial in the search for life. You want a habitat that endures for a long time.
Original Source: NASA/JPL News Release