Sandy desert

Features

Other non-sandy deserts consist of exposed outcrops of bedrock, dry soils or aridisols, and a variety of landforms affected by flowing water, such as alluvial fans, sinks or playas, temporary or permanent lakes, and oases. A hamada is a type of desert landscape consisting of a high rocky plateau where the sand has been removed by aeolian processes. Other landforms include plains largely covered by gravels and angular boulders, from which the finer particles have been stripped by the wind. These are called "reg" in the western Sahara, "serir" in the eastern Sahara, "gibber plains" in Australia and "saï" in central Asia. The Tassili Plateau in Algeria is a jumble of eroded sandstoneoutcrops, canyons, blocks, pinnacles, fissures, slabs and ravines. In some places the wind has carved holes or arches, and in others, it has created mushroom-like pillars narrower at the base than the top. On the Colorado Plateau, it is water that has been the prevailing eroding force. Here, rivers, such as the Colorado, have cut their way over the millennia through the high desert floor, creating canyons that are over a mile (6,000 feet or 1,800 meters) deep in places, exposing strata that are over two billion years old.