Giving the Desert a Coat of Varnish
After every few thousand years, it is always a good idea to give your desert a new coat of varnish or stain to vertical rock surfaces. It not only helps protect the rocks, but adds aesthetic appeal. Actually, people do not need to perform this task at all; it is being done for us. It is a very thin coating that is in the range of dark red colors, even to nearly black. The color results from the amount of manganese and iron , and is mostly from atmospheric dust. Native Americans scratched out their own graffiti in it. Credit: NPS / Neal Herbert (usage does not imply endorsement of site contents) Scientists now have a better handle on how the stuff originates: microbes in photosynthetic bacteria. (Researchers must have thought the science wasn't quite good enough, so they threw in a few Hail Darwins to make it sciency science. This taints it.) The amount of deposition, however, defies uniformitarian (slow and gradual processes over a mighty long time) assumptions. Instead, it is ye