Seems to me that we've got to have a showing that there ever was a lake in Pollack Crater in Sabaeus.

Looks like a step has been skipped -- so often the case with Mars study. The presence of an ancient lake is just assumed like the presence of all those peroxides and superoxides supposedly sterilizing the soil, or the assumption that ultraviolet flux is lethal at the surface without measuring it, and the assumption that all the dark streaks on surface slopes are "dust avalanches" revealing the dark clean surface beneath. It's a very useful assumption, but no one has established that the underlying surface is naturally dark on all slopes.



Pollack Crater is at about +2km elevation, which somewhat lessens the likelihood that it ever hosted a lake.

Becquerel Crater, on the other hand, is apparently at a +/-0 elevation -- making a lake somewhat more likely, but there is still no showing that there ever was a lake there. The way erosion has occurred around and within the crater looks to me like an icy regime, with a good deal of subsurface heating and the repeated release of some kind of viscous melt, the most recent of which is the remnant "White Rock" in Becquerel -- and possibly in all the craters where these formations are found.

That notion actually has no affect one way or another on the possiblility of life on Mars or on the possibility that the "White Rock" formations are biological remnants of some sort. They could be. We just don't know. And it looks like there's no way to tell remotely.

So the answer is to go to Mars and find out!

Let's go!

Cheers, BRFelix