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Submarine Canyons are a class of narrow steep-sided valleys that cut into continental slopes and continental rises of the oceans. Submarine canyons form on continental slopes or on the continental shelf. They are uncommon on continental margins with steep continental slopes or escarpments. Submarine Canyons are named after the canyons formed by rivers on land. Undersea canyons are found along the slopes of most continental margins, as opposed to deep-sea trenches, which are found where one tectonic plate slides beneath another.
They form due to erosion caused by sediments carried down by rivers that cut across continental shelves, slopes, and rises. The sediments are subsequently deposited on the abyssal plains.
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Submarine Canyons Characteristics
Submarine canyons are more common on the steep slopes of active margins than on the gentler slopes of passive margins. They demonstrate erosion across all substrates, from unlithified sediment to crystalline rock. Canyons on active continental margins are steeper, shorter, more dendritic, and more closely spaced than canyons on passive continental margins.
The walls are typically very steep and can reach near-vertical heights. The walls are vulnerable to bioerosion and slumping. There are approximately 9,477 submarine canyons on Earth, accounting for approximately 11% of the continental slope.
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Submarine Canyons Diagram
Submarine Canyons Types
These marine features are formed due to erosional, depositional and biological activity. They are usually found in the upper parts of the elevations since they are produced upon features of diastrophic origins. There are broadly three types of submarine canyons:
A bank is a flat-topped elevation, usually located in the continental margins. Erosional and depositional activities are the major factors for the formation of banks. There is a thin layer of water over the bank; however, the depth is sufficient for navigation. They are productive sites for fisheries. For example the Dogger Bank in the North Sea and the Grand Banks of the North-Western Atlantic.
Shoal is an accumulation of sediment in a river channel or on a continental shelf that is potentially dangerous to ships. It is conventionally taken to be less than 10 m (33 feet) below water level at low tide on the continental shelf.
A Coral Reef is a ridge or hummock formed in shallow ocean areas by algae and calcareous skeletons, usually coral polyps. A coral reef has the potential to become a permanent coral island. Coral reefs, also known as “rainforests of the sea,” are home to a diverse range of organisms. Coral reefs are a characteristic feature of the Pacific Ocean, associated with seamounts and guyots.
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Submarine Canyons UPSC
The motion of seawater is controlled by ocean relief. In turn, oceanic movement in the form of currents causes many variations in both the oceans and the atmosphere. Ocean bottom relief also has an impact on navigation and fishing.
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