Dune cannibals

A piece of Mars: Dunes often cannibalize each other, with new dunes forming from the sand in older dunes. Here the tan dunes have formed from the sand that made up the grayish blue dunes. Notice the banding on the bluish dunes — this is a sign of erosion. The banding is probably layering in

A beautiful tangle

A piece of Mars: Compare this with my post five days ago and you might think the scenes are similar. In fact they’re not. In the previous case sedimentary layers were carved out by the wind, leaving behind swirly patterns where resistant layers created relief. Here, the swirly patterns are inherent in the rock. These