Marine sediments are produced by weathering of rocks into particles or by accumulation of shells of dead organisms which are then transported by air, water or ice and deposited in an ocean basin. Sediments can be classified either by their grain size into gravel, sand, silt, clay and colloid, or on the basis of their mode of formation -terrigenous, biogenic, authigenic, volcanogenic and cosmogenic sediments. Once sediment is moving, current velocity necessary to transport grains varies directly with particle size. For a given grain diameter, deposition occurs when the current speed is less than some critical value defined on the graph.
Continental shelves represent the submerged edge of a continent.
Sediment distribution in the oceans follows a regular pattern of different sediment types that vary with latitude and depend on climate. For example, biogenic sediments are abundant at the Equator and on the western edges of the oceans while terrigenous sediments dominate in middle or temperate latitudes.