NASA MRO Image of Mars: Cratered Dune Forms

Known since at least 2003, this is a wonderful case of aeolian sandstone that (a) preserves its original sand dune bedform shapes and (b) lies unconformably over a previously-eroded surface of layered sedimentary rock. Larger image.

Known since at least 2003, this is a wonderful case of aeolian sandstone that (a) preserves its original sand dune bedform shapes and (b) lies unconformably over a previously-eroded surface of layered sedimentary rock. Larger image.