Gibber

A desert pavement, also called reg (in western Sahara), serir (in eastern Sahara), gibber (in Australia), hamada (western Sahara and Middle East), or saï (in central Asia) is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size. They typically top alluvial fans. Desert varnish collects on the exposed surface rocks over time. The presence of desert pavement typically is used as an indicator for the aridity of an area and the relative age of geomorphic surfaces.

Geologists debate the mechanics of pavement formation and their age. Studies look at pavements on alluvial surfaces and show that older surfaces have more developed pavements with small, angular rocks that are well sorted and tightly packed together.