ABYSSAL DEPOSITS (EN: abyssal deposits, deep sea deposits; DE: Tiefseeablagerungen, abyssische Ablagerungen; FR: depots abyssaux; ES: depysitos abisales; RU: абиссальные отложения) are the deep sea deposits, occupying about 90% of the area of the world ocean floor. These deposits lay mostly at the depth of over 3 kilometres.

Depending on the predominance of the particles of the specific origin, the abyssal deposits are divided into the organogenic and polygenic types. The organogenic abyssal deposits include the loose or compacted sediments, derived largely from the skeletons of the planktonic organisms, such as the lime (foraminiferal, globigerinal) ooze and the siliceous (diatomaceous, radiolarian) ooze. The polygenic abyssal deposits are represented by the pelagic red clay.

The iron-manganese nodules are among the most typical inclusions of the red clay.