After reading this article you will learn about:- 1. The Bottom Configuration of the Pacific Ocean 2. The Bottom Configuration of the Atlantic Ocean 3. The Bottom Configuration of the Indian Ocean 4. Bottom Configuration of the Arctic and Southern Oceans.
1. The Bottom Configuration of the Pacific Ocean:
The Pacific is the largest ocean. It covers about 35 per cent of the earth’s surface. It is about 16000 km from north to south.
The continental shelf of the Pacific is generally narrow. It is relatively wide only in the north-eastern coast. The east coast of the pacific, i.e., west coast of America is simple. There are large numbers of islands, big and small in the western and southern parts of the pacific.
The important islands like Kurile, Japan, Ryukyu, Philippines, Indonesia, the Malanesian, Micronesian, and Polynesian islands are either of volcanic or coral origin. Australia, Tasmania and New Zealand are the islands of the south-west Pacific. The Aleutian in the north and the Hawaiian islands in the middle are the other important- islands of the Pacific. In the eastern part of the Pacific there are no islands.
The average depth of the Pacific is about 3700 metres. The floor of the Pacific in the eastern part rises to form a submarine plateau, called Albatross Plateau. In the south, there is a submarine ridge running from north to south. It is called the Pacific Antarctic Submarine Ridge.
There is a large number of trenches in the Pacific ocean. Among them the Mariana Deep located on the east of Philippine islands is the deepest (10870 metres). This is the deepest trench in the world. The other trench close to it is the Mindando Trench or the Philippine Trench (10797 metres).
Towards north of it in the east of Japan, is the Japan Trench (8490 metres), and Kurile Trench (8519 metres) is in the east of Kurile islands and the Aleutian islands. In the south central part of the Pacific Ocean there are two other trenches named Tonga and Kermadoc Trenches. In the south-east along the Chilean coast there is the Aracama Trench.
2. The Bottom Configuration of the Atlantic Ocean:
The Atlantic Ocean covers about one-sixth of the total area of the world. The length of the ocean is 15000 km and the breadth on the equatorial region is 2000 km. Its continental shelf is wide. There are many shallow seas on the continental shelf. The chief islands on the east coast are Great Britain, Ireland, Azores, Madeira, Canary, Cape Verde, etc. The New Foundland, West Indies and Falkland are the main islands of the west coast. Greenland and Iceland are in the north.
The average depth of the northern part of the Atlantic is only 1000 metres. But towards south the depth is about 3660 metres (average). There is a longitudinal submarine ridge at the centre of the Atlantic Ocean. Its depth is about 3000 metres. This ridge is known as the Mid-Atlantic Ridge. The northern part of the ridge is called the Dolphin Ridge.
The Dolphin widens towards further north to form a broad plateau, known as Telegraph Plateau. The southern part of the Mid-Atlantic Ridge is called the Challenger Ridge. To the south-west of this ridge is the Rio-Grande Ridge. The Walvis Ridge runs from the Challenger Ridge towards the African coast.
The number of deeps in the floor of the Atlantic Ocean is not many. Among them the Puerto Rico Trench (8510 metres) is the deepest. It lies near the West Indies. The other important deeps are the Romanche Trench (7320 metres) near the Mid Atlantic Ridge and South Sandwich Trench (7230 metres) near the South Sandwich island in the South Atlantic.
3. The Bottom Configuration of the Indian Ocean:
The Indian Ocean covers an area of 74 million sq. km. It occupies nearly 14 per cent of the area of the surface of the earth. The ocean is surrounded on three sides—east, north and west, by the continents and island.
The continental shelf of the Indian Ocean is narrow. The shelf between the Andaman Islands and Burma and that near the Persian Gulf and Red Sea are fairly wide.
There are a small number of islands in the Indian Ocean. The major islands of the eastern part are the Andaman and Nicobar. Sri Lanka is situated in the north. The Socotra and Malagasy or Madagascar is located in the west. They are all continental islands. Besides, there are coral and volcanic islands in the mid ocean. Among these islands Laccadive, Maldivi, Chagos, Seychelles, Mauritius and Reunion are well known. There are three more islands in the south, namely, New Amsterdam, Crozet and Karguelon.
The Indian Ocean is generally deep. Its floor has a depth of more than 3660 metres. There is a submarine ridge starting from Laccadive to the Antarctica on the floor of the ocean. The northern part of the ridge is called Laccadive-Chagos Ridge, the middle part is known as the Chagos St. Paul Ridge and the southern portion is called St. Paul Amsterdam Plateau.
Over and above there is a north-south ridge on the floor of the Arabian Sea. A rise starting from Andaman and Nicobar along the 90° longitude to Antarctica is also seen on the floor of the Indian Ocean.
The number of trenches in the ocean is very few. The only important trench is the Sunda Trench, (7320 metres) which lies south of Indonesia.
4. Bottom Configuration of the Arctic and Southern Oceans:
These two oceans remain frozen practically for the whole year. There is little knowledge about the bottom configuration of these two oceans. The average depth of the Arctic ocean is about 3750 metres, and that of the Southern ocean is 7000 metres.