Talk:Calcium carbonate

I do wonder what's under all that suspiciously flat terrain in the North of Mars. A lot of ice, apparently, but what else? Is it all wind blown sand, or was there some water based erosion as well? And carbonates?

There are also large areas where the geological survey map proposes Gypsum generation, whatever that is. I guess gypsum, as a sulfate, by definition is not a carbonate. But it might be useful as a construction material none the less?