Sand covers only about 20 percent of the Earth's deserts. Nearly 50 ...
Sand covers only about 20 percent of the Earth's deserts. Nearly 50 percent of desert surfaces are gravel plains where removal of fine-grained material by the wind has exposed loose gravel and occasional cobbles. This web page, produced by the U.S. Geological Survey, features text and photographs that describe desert landforms, soils, plants, and the role of water in the formation of desert landscapes.