Desert pavement

[3] A common theory suggests that they form through the gradual removal of sand, dust and other fine-grained material by the wind and intermittent rain, leaving the larger fragments behind.

The larger fragments are shaken into place through the forces of rain, running water, wind, gravity, creep, thermal expansion and contraction, wetting and drying, frost heaving, animal traffic, and the Earth's constant microseismic vibrations.

The removal of small particles by wind does not continue indefinitely, because once the pavement forms, it acts as a barrier to resist further erosion.

The small particles collect underneath the pavement surface, forming a vesicular A soil horizon (designated "Av").

A newer theory of pavement formation comes from studies of places such as Cima Dome, in the Mojave Desert of California, by Stephen Wells and his coworkers.

"[4] While the stones remain on the surface due to heave, deposition of windblown dust must build up the soil beneath that pavement.