Hemipelagic sediment

Deposition

Hemipelagic sediment dispersal is mainly controlled by fluvial discharge. Dispersal rate is influenced by sea-level variations which change the proximity of river mouths to oceanic basins and by oceanographic phenomena like currents. Sea-level variations are caused by the earth's natural oscillation between glacial and interglacial periods. For example, a low average sea level would occur during a glacial period as more water is held in ice caps. In addition, underwater landslides called turbidity currents can transport hemipelagic sediment from the continental slope to the continental rise and form a turbidite sequence.

Typically, hemipelagic sediment is transported to the continental slope in suspension from river mouths but can be transported by the wind. The rate of deposition of hemipelagic sediment is higher than pelagic sediment but still quite slow. Ordinarily hemipelagic sediments accumulate too rapidly to react chemically with seawater. In most cases, individual grains thus retain characteristics imparted to them in the area where they formed.