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 yet another indication that Earth was created recently.

If you have driven any time in the southwest USA, you have undoubtedly noticed the dark, glossy sheen on sandstone cliffs. It’s called “desert varnish.” But did you know it is biological in origin?

Desert varnish, or rock varnish, is found around the world in desert environments. A press release from Stanford’s SLAC National Accelerator Laboratory points out that Charles Darwin observed “glittering rocks” on his voyage on the Beagle, as did explorer Alexander von Humboldt before him. What is it? How does it form, and why?

To read the rest, head on over to "Desert Varnish Goes Biological".