Abyssal plain

An abyssal plain is a broad, nearly level region of the deep ocean floor, typically blanketed by fine sediment at depths of roughly 3,000–6,000 meters.

Turbidity current: A dense, sediment-laden flow that travels downslope through water, often along the seabed. These flows carry sediment from continental margins into deep basins and spread it across plains.
Continental rise: A gently sloping region of sediment at the base of a continental slope. It is a common source and route for sediment moving toward abyssal plains.
Polymetallic nodule: A mineral-rich, roughly rounded concretion that grows slowly on parts of the deep seafloor. Nodules on some abyssal plains are targets of proposed deep-sea mining.
Sohm Abyssal Plain: A large abyssal plain in the western North Atlantic, south of Newfoundland. It is a well-known example of a sediment-covered plain in the North Atlantic.
Turbidite: A sediment deposit formed by a turbidity current, commonly showing layers sorted by grain size. Repeated turbidite deposits can bury seafloor relief beneath thick, flat sediment.
Continental slope: The steep seafloor descent from a continental shelf toward the deep ocean basin. Its canyons and slopes channel sediment flows that can reach the plain.
Deep-sea mining: The extraction of mineral resources from deep ocean waters and the seabed. Mining proposals focus on plains where nodules are abundant, raising concerns about lasting habitat damage.
Hatteras Abyssal Plain: An abyssal plain in the western North Atlantic off the southeastern United States. Its location illustrates the extensive abyssal plains bordering continental margins.
Pelagic sediment: Fine-grained material that settles through the water column and accumulates on the deep seafloor. Its slow, widespread accumulation adds a fine cover between episodic sediment flows.
Mid-ocean ridge: A continuous underwater mountain chain where tectonic plates diverge and new oceanic crust forms. Ridges rise far above abyssal plains and divide ocean basins.

Linked from 21 pages