Remnants of erosion

A Piece of Mars: The gray area in the center of the 480×270 m (0.3×0.17 mi) area is an erosional remnant: once, more of this area was covered by the gray stuff, but some of it has eroded away (most likely by the wind) to reveal the underlying terrain below. The wind probably blew from upper left to lower right, lifting away the finer grains and leaving behind the larger, heavier ones. Some of the larger grains have formed into ripples, that in some places may be the only sign that the overlying layer was ever there. (HiRISE ESP_043136_2020, NASA/JPL/Univ. of Arizona)