What an interesting tidbit from Squyres. Baslat under the duricust. I wouldn't go looking for sabkas on basalt. IMHO this is looking very much what would be expected from extraordinarily long episodic periods of aeolian deposition of basaltic dusts to which is occasionally added emissions from volcanic activity +/- meterorite & comet impacts. Naturally there are crossbeds in such deposits but water. IMHO, still unlikely. ps why not sabkas? Becasue acid-saline waters tend to differentially move many major and trace metals and there is still no evidence of that in any data release to date.