Thanks for reminding me of a couple of blind spots I need to allow for. One is, obviously, assuming all craters are impact craters, and not seeing the signs of subsidence. So obvious with the blinders removed. And much more interesting, for the rich story it suggests of "ice or salt tectonics at play". A wonderful turn of phrase for the imagery it evokes. And thus I should avoid unconscious assumptions about a solid surface and what lies beneath. These little planetoids ought to be lumpier than my familiar large terrestrial home, and who knows what you might turn up scratching the surface at any particular spot.

Fascinating place, this solar system.