An ancient, watery Mars was not always an acid bath
Drawn to Mars largely by signs of past Earth-like conditions, researchers have finally found definitive relics of gently lapping seas and balmier skies: in particular, deposits of sulfate salts. To form those sulfates, though, the ancient seas must have been acidic enough to burn off skin.
But a different tale is told by another class of minerals, fully mapped only recently: clays. They suggest that even before the era of the sulfates, Mars was drenched in water safe enough to dunk a hand in. “The clays indicate alteration with a lot of water,” says Fran?ois Poulet of the University of Paris-South, a member of the discovery team. “The sulfate indicates a second step in the climate of Mars.”
Looks like Bruce MacKenzie will have a ready supply of brickmaking materials.