It covers 38% of the ocean floor and accumulates more slowly than any other sediment type, at only 0.1–0.5 cm/1000 yr.[1] Containing less than 30% biogenic material, it consists of sediment that remains after the dissolution of both calcareous and siliceous biogenic particles while they settled through the water column.
[2] These pelagic sediments are typically bright red to chocolate brown in color.
Both wind and ocean currents transport these sediments in suspension thousands of kilometers from their terrestrial source.
As they are transported, the finer clays may stay in suspension for a hundred years or more within the water column before they settle to the ocean bottom.
The settling of this clay-size sediment occurs primarily by the formation of clay aggregates by flocculation and by their incorporation into fecal pellets by pelagic organisms.