Desert Pavement

February 12, 2015

Desert Pavement

Photographer: Wendy Van Norden
Summary Authors: Wendy Van Norden; Jackie Phillips

Desert pavement is a layer of interlocking pebbles that protect smaller sediments below. The photos above demonstrate this - when a rock is removed a layer of sand can be found below. Wind easily removes the sand, leaving only the larger pebbles behind. Deflation, the lowering of the land surface by the removal of sand, silt and clay by wind erosion, has been long supposed responsible for the formation of desert pavement.

There is evidence that other factors may be at work, as well. One theory states that the rocks are lifted to the surface by shrinking and swelling of clay layers below. New evidence from the Cima Dome area of the Mojave Desert suggests that the pebbles started at the surface and smaller sediments were deposited around them.

Regardless of how it forms, once desert pavement is in place, it helps shield any underlying sediments from eroding away. Photo taken on January 3, 2015 in Death Valley National Park.

Photo details: Left - Camera Maker: Apple; Camera Model: iPhone 5s; Focal Length: 4.15mm (35mm equivalent: 39mm); Aperture: ƒ/2.2; Exposure Time: 0.0006 s (1/1786); ISO equiv: 32; Right - same except:
Exposure Time: 0.0005 s (1/1953).