Desert varnish or rock varnish is an orange-yellow to black coating found on exposed rock surfaces in arid environments. Desert varnish is usually around one micron thick and present nanometre-scale layering. Rock rust and desert patina are other terms which are also used for the condition, but less often.
... Secondly, it has been proposed that desert pavement forms from the shrink/swell properties of the clay underneath the pavement when precipitation is absorbed by clay it causes it to expand and later ... theory of pavement formation comes from careful studies of places like Cima Dome, in the Mojave Desert of California, by Stephen Wells and his coworkers ... are partly covered by younger soil layers that have desert pavement on top of them, made of rubble from the same lava ...
... Originally scientists thought that the varnish was made from substances drawn out of the rocks it coats ... observations, however, show that a major part of varnish is clay, which could only arrive by wind ... react together when the rock reaches high temperatures in the desert sun ...
Famous quotes containing the words varnish and/or desert:
“People are less self-conscious in the intimacy of family life and during the anxiety of a great sorrow. The dazzling varnish of an extreme politeness is then less in evidence, and the true qualities of the heart regain their proper proportions.”
—Stendhal [Marie Henri Beyle] (17831842)
“What eer you are
That in this desert inaccessible,
Under the shade of melancholy boughs,
Lose and neglect the creeping hours of time.”
—William Shakespeare (15641616)