A Piece of Mars: Here’s a tiny bit (0.69×0.39 km or 0.43×0.24 mi) of Jezero crater, one of the candidate landing sites for the Mars 2020 rover. On the bottom and left is high-standing volcanic terrain, former lava that flowed out on the crater floor. On the upper right is a much older deposit of stuff that piled up at the bottom of the lake that once, more than 3.5 billion years ago, filled the crater. Those lake deposits are so easy to erode that they’ve been worn down by the wind (see those bedforms there?) to the point that they’re now lower than the volcanic stuff. I wonder if they’ll eventually be completely covered by those ripples. (HiRISE ESP_037330_1990, NASA/JPL/Univ. of Arizona)
Schon, S. C., J. W. Head, and C. I. Fassett (2012), An overfilled lacustrine system and progradational delta in Jezero crater, Mars: Implications for Noachian climate, Planet. Space Sci., 67(1), 28–45, doi:10.1016/j.pss.2012.02.003.