A trio of ancient mesas is rewriting what we know about wind, sand, and deep-time geology, captured in stunning detail from space. Ancient Sandstone Origins and Rock Varnish FormationThe mesas are geological remnants of a Paleozoic sandstone formation, dating back over 250 million years. Each mesa is coated in a thin layer of rock varnish, a dark substance rich in manganese and iron oxides. Further Monitoring and Data PotentialNASA’s Earth Science and Remote Sensing Unit continues to monitor the region for changes in dune structure and surface albedo. There is also interest in the chemical composition of the rock varnish itself.