Transportation and Deposition of Sand

Abstract

Gravity acting alone moves sand down the slip slope of a dune, of an oversteepened submarine slope, and powers a debris flow. Continental and alpine glaciers also move sand and probably a significant number of the world’s sand grains have, at one time or another in their history, been transported by ice. But the dominant agents are water and wind. Although one can but surmise, probably every sand grain on earth, from loose sand on a modern Chilean beach to sand in an early Precambrian quartzite in Canada, has been transported millions of times by water and thousands of times by wind, either on a continental desert, in coastal dunes, or on a dry floodplain. Thus streams and rivers, tidal and longshore currents in shallow water, waves in shallow water, contour currents in deep water along continental margins, density currents in oceans and deep lakes, wind, and ash flows and falls from volcanic explosions are the dominant agents that transport and sort sand and segregate it from mud, silt, and coarse particles.