The deep marine segment comprises the continental slope and deep basin floor and is the final destination in the sediment cascade from source to sink. The morphology of the continental slope is strongly influenced by the sediment supply of rivers. Sediment is ponded in intra-slope basins formed by salt and shale withdrawal, and also accumulates in submarine valleys and as drapes on graded slopes. Much of the sediment delivery to the deep sea, however, is via canyons incised into the continental shelf and slope, particularly where they intersect littoral cells. Some canyons located at passive margins feed deep sea fans that exceed 1 million square kilometers in surface area. Fans at active margins are generally two orders of magntiude smaller. Deep sea fans are nourished with sediment at any stand of sea level, including at highstands when deltas transit the continental shelf to the shelf-slope break. By far the greatest fluxes of water in the deep sea are caused by the thermohaline circulation, which transports and deposits fine particles in sediment drifts as contourites. Deep sea sediments record contain a high-fidelity record of Quaternary glacial-interglacial cycles.