Why is desert pavement covered with stones?
Desert pavement is a closely packed surface layer of pebbles and small stones in dry regions. Its underlying sediment and formation history vary among locations.
Separating fine grains
Wind removing silt and sand selectively can concentrate larger stones at the surface. In some places, dust deposition and movement within the soil also help position stones. Thus wind stripping alone does not explain every pavement. A dense stone cover can in turn limit renewed loss of the fine material below.
A fragile surface arrangement
Soil crust and living cover beneath stones may have developed slowly. Vehicle tracks and excavations can disrupt them and expose new dust sources. Dark desert varnish occurs on some rocks, but is neither universal nor a reliable age measurement on its own. Desert pavement is a natural gravel armour rather than a sandy road, and local sections are needed to test formation explanations.