The Shape and size of the Atlantic ocean
The Atlantic Ocean extends over about 16.5% of the total area of the earth. This percentage does not include that of its marginal seas. The area of this ocean is about 50% of the Pacific Ocean. The most striking feature about the bottom of the Atlantic is the presence of the Mid- Atlantic Ridge that divides this ocean in half.
This ridge extends 2.5 km above the deep-sea plains on either side. This submarine ridge slopes gently towards the deep-sea plain on either side. It is S-shaped following the general trend of the coastlines.
On the eastern side, the coast of Saharan Africa bulges towards the west, while the north coast of South America recedes into the Caribbean Sea; while the Cape Sao Roque projects eastwards, the Gulf of Guinea recedes in the same direction.
From the nature of the shape of the respective coasts together with other geological and bio-logical evidences, it becomes amply clear that in the remote past the continents on both the sides of the present ocean must have been parts of a single land-mass.
This ocean basin becomes narrower towards the equator. The distance between the Liberian coast of Africa and Cape Sao Roque is only 2560 km. To the north of equator the North Atlantic Basin is 4800 km wide in latitude 40HN.
While the South Atlantic Basin is 5920 km. wide in latitude 35°S. Whereas the South Atlantic opens broadly into the Southern Ocean, the North Atlantic is rather enclosed by Greenland and Iceland.
