Good to read you again, Felix . . .
Carbonates could also explain the sea of drifting black dunes on Mars. As sure as Mars has geology, there is a form of petroleum to be found there.
I like the mention, too, of a "strongly saline or acidic solution." A collection of Death Valley's alkali pools comes to mind. Nasty business. Do not drink.
Type more, and often.
Cheers back at’chas.