Question:
Explain the main sources of ocean deposits and their vertical distribution on the ocean floor. (64th BPSC 2019)
Answer.
Ocean deposits are sediments that may be inorganics or organics that come from mainly continents by different means and get deposited on the ocean floor.
The following are the main sources of ocean deposits:
- Terrestrial sediments
- Volcanos sediments
- Marine Organism
- Extraterrestrial
- Waste generated by Human
Terrestrial sediments:
Both biotic and abiotic sediments[ weathered materials] are transported and deposited by rivers, winds, and waves from continents to different parts of oceans such as a continental shelf, slope, ocean floor, etc.
Volcanos sediments:
Some oceanic sediments are of volcanic origin. Due to volcanic eruptions at the ocean or continents, volcanic sediments such as dust particles get deposited in the ocean directly or indirectly by the act of the air.
Marine Organism:
The main sources of Ooze deposits [ organic substance] in the deep ocean are dead marine organism that derives from Zooplankton and Phytoplankton.
Extraterrestrial:
Some of the ocean deposits come from the sediments from meteorites.
Waste generated from human activities:
Nowadays, there are other types of ocean deposits comprised of plastic, industrial waste, domestic waste, etc. that come from human settlements directly or indirectly.
Vertical distribution of ocean deposits on the ocean floor:
The following are the sequence of the vertical distribution of ocean deposits in the increasing order of depth:
- Terrigenous deposits
- Mud
- Calcareous Oozes
- Siliceous Oozes
- Red Clay
Terrigenous deposits:
Terrigenous deposits such as sand, gravel, rocks, etc are found on the continental shelf or shallow ocean.
Mud:
Muds are very finer sediments that are found in the continental slope and abyssal plain.
Calcareous Oozes:
It is one type of Pelagic deposit that is found in the deep ocean. Calcareous Oozes are made up of calcium carbonates that are generally produced by marine Mollusca and single-cell Protozoans.
Siliceous Oozes:
Siliceous Oozes are of organic origin made up of silica; mostly found in Phytoplankton and diatom. It is one type of Pelagic deposit that is found in the deep ocean[ deeper than calcareous Oozes].
Red Clay:
Red clays are the one type of pelagic deposit found in the deepest and most remote locations of the ocean. It is comprised of both organic and inorganic substances with very finer particles. Presence of iron and manganese, and meteorite dust.
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