Water covers 70% of the earth’s surface in which only 3% are fresh water (Of this, 2% is in polar ice caps and only 1% is usable water). Oceans make up around 67 percent of the Earth's surface. The relief features of the oceans are quite different from the continental features because the Oceanic crust is less than 60-70- million years old whereas continental features are of Proterozoic age (Over 1 Billion years old). Here, we are giving easy-to-learn write-up on the Oceanic topography along with typology and significance that will enhance the knowledge of aspirant who are preparing for different competitive exams.
The Oceanic relief features are in the form of mountains, basins, plateaus, ridges, canyons and trenches beneath the ocean water. These forms are called Submarine Relief. The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.
It is the submerged edge of a continent which is gently sloping plain. In other words, it is an extension of the continents into the ocean; continental shelf land would be exposed if sea level dropped. Siberian Shelf in the Arctic Ocean is the largest continental shelf in the world. It is made up of granite rock.
It is the slope between the outer edge of the continental shelf and the deep ocean floor, which are lying between 2 degrees and 5 degrees.
It connects the continental slope to the deep sea or abyssal plain which is around 100-1000 Km wide.
It is the lowest layer in the Ocean, which is covered by the sediments of basalt up to 5 kilometres thick.
Abyssal Plains and Abyssal Hills
It is flat, cold and sediment covered ocean floor. They are more extensive in the Atlantic and Indian Oceans and less extensive in the Pacific Ocean.
It is elliptical projections from the sea floor, which look like mountains and have a steep slope of around 22 degree to 24 degrees.
It is also known as a tablemount, is an isolated underwater volcanic mountain, with a flat top over 200 m below the surface of the sea. The diameters of these flat summits can exceed 10 km. It is inactive ocean volcanoes with flat top.
It is topographic depression of the sea floor, relatively narrow in width, but very long. It is the deepest part of the ocean. Mariana Trench or Marianas Trench is the deepest part of the world's oceans, whereas Tonga Trench is Steepest Trench of the World.
1. It controls the motion of sea water.
2. It influences the oceanic movement in the form of currents.
3. It helps in the navigation and fishing.
In the above write-up on the Oceanic topography along with typology and significance will enhance the general knowledge of the readers.