Ocean deposits Ocean Deposits - The ocean floor is almost covered with a blanket of sediments. The marine deposits are the outcome of deposition of sediments due to continuous wearing of rocks along with the other material such as the remains of marine animals and plants.
Classification of ocean deposits On the basis of depth A) Deep sea deposits- (below 100 fathoms) I) Pelagic deposits Red clay Radiolarian ooze Diatom ooze Globigerina ooze Pteropod ooze II) Terrigenous deposits Blue mud Red mud Green mud Coral mud Volcanic mud B) shallow sea deposits-(between low tide water and 100 fathoms) Gravels Sands Mud C) littoral deposits- (between high and low tide water)
General classification On the basis of location- Sir John Murray and j.t. Jenkins classified into the following two categories Shelf deposits Pelagic deposits General classification Terrigenous deposits Littoral deposits Shallow water deposits Terrigenous mud Neritic deposits Shallow water neritic deposits Deep seawater neritic deposits Pelagic deposits.
Distribution of ocean deposits Distribution of ocean deposits may be attempted in various ways as follows: Vertical distribution of ocean deposits Regional distribution (ocean-wise distribution) Marine province-wise distribution, such as ocean deposits on continental shelves, and on deep sea plains. Sediment-wise distribution, such as terrigenous deposits, and pelagic deposits.
Sediment-wise distribution Distribution of terrigenous deposits Terrigenous deposits include gravels, sands, muds and volcanic materials etc. Which are derived through weathering and erosion of continental rocks by various denudational processes. The sequence of these materials from the coast towards the sea is gravel, sand, silt, clay and mud. Terrigenous deposits are classified into 3 categories Littoral deposits Shallow water deposits Deep water deposits
Littoral deposits- found on the continental shelves mainly near the coastal margins up to the depth of 100 fathoms (600 feet) but they have been also traced upto the depth of 1000 m-2000 m. Littoral deposits consist of gravels, sands, silt, clays and muds. Shallow water deposits –terrigenous sediments deposited between low tide water and 100-fathom depth. These deposits consist of gravels, sands, silt and clays of varying proportions. Sea waves and tidal waves help in the gradation and sorting of sediments but undersea landslides, slumping, strong storm waves, and storms some times disturb the vertical stratification of sediments. Deep water deposits- the sediments deposited below the depth of 100 fathoms. There is marked gradation of sediments in vertical succession where the sequence of sediments with increasing depths is blue mud, red mud, green mud, coral mud and volcanic mud.
Distribution of pelagic deposits Pelagic deposits consisting of remains of marine plants and animals in the form of different types of oozes cover about 75.5 per cent of the ocean areas. Red clay constitutes 31.1 percent of the total ocean deposits.