A self-portrait of NASA’s Curiosity rover taken on June 15, 2018, during the 2,082nd Martian day, or sol, of Curiosity’s work on Mars.
Today, Mars is a planet of extremes — it’s bitterly cold, has high radiation, and is bone-dry.
But billions of years ago, Mars was home to lake systems that could have sustained microbial life. As the planet’s climate changed, one such lake — in Mars’ Gale Crater — slowly dried out.
Scientists have new evidence that super salty water, or brines, seeped deep through the cracks, between grains of soil in the parched lake bottom and altered the clay mineral-rich layers beneath.
The findings published in the July 9 edition of the journal Science and led by the team in charge of the Chemistry and Mineralogy, or CheMin, instrument — aboard NASA’s Mars Science Laboratory Curiosity rover — help add to the understanding of where the rock record preserved or destroyed evidence of Mars’ past and possible signs of ancient life.
“We used to think that once these layers of clay minerals formed at the bottom of the lake in Gale Crater, they stayed that way, preserving the moment in time they formed for billions of years,” said Tom Bristow, CheMin principal investigator and lead author of the paper at NASA’s Ames Research Center in California’s Silicon Valley. “But later brines broke down these clay minerals in some places – essentially re-setting the rock record.”