There are mountains, basins, plateaus, ridges, canyons and trenches beneath the ocean water too. These relief features found on the ocean floor are called Submarine Relief. The ocean
basins are broadly divided into four major subdivisions. They are;
- Continental Shelf: They slope seaward from coast to a point where the slope becomes very steep. This shallow submerged extension of the continent is called as the Continental Shelf.
- Continental slope: The continuous sloping portion of the continental margin, seaward of the continental shelf and extending down to the deep sea floor of the abyssal plain, is known as Continental Slope.
- Abyssal plains : Abyssal plains are the extremely flat and featureless plains of the deep ocean floor. Abyssal plains are considered as the levelest areas on the earth. They cover a major portion of the ocean floors between the depths of 3000m to 6000m.
- The ocean deeps/ submarine trenches : The ocean deeps are the deepest part of the ocean. They are generally called submarine trenches. These trenches are not always located in the middle of the ocean basins. They may be very close or parallel to the continents bordered by Fold Mountains.