In the past decade, astronomers have observed clay materials on Mars that seem to indicate large bodies of water once filled the Martian surface. But new research suggests that magma could form some of these slick deposits rapidly, and ancient Mars may not have been as wet as we thought.
A region of French Polynesia has similar deposits of these strange clays, which scientists found were formed by cooling magma rather than water.
"It was the first time that clays were shown to originate from another process than aqueous alteration," researcher Alain Meunier, of the Université de Poitiers in France, told SPACE.com by email. "The consequence was that, even if clays need water to be formed, this does not mean that they need liquid water."
Since water is thought to be essential for all life, the Martian clay findings complicate the question of whether early Mars was likely to have been hospitable to life.
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