Continental Self

News: India raises continental-shelf claim in Arabian Sea region by nearly 10,000 square km.

About Continental Shelf

The ocean floors can be divided into four major divisions: (i) Continental Shelf; (ii) Continental Slope; (iii) Deep Sea Plain; (iv) Oceanic Deeps. Besides, these divisions there are also major and minor relief features in the ocean floors like ridges, hills, sea mounts, guyots, trenches, canyons, etc.

Continental Shelf

• It is the extended margin of each continent occupied by relatively shallow seas and gulfs.
• It is the shallowest part of the ocean showing an average gradient of 1° or even less.
• Shelf break: The shelf typically ends at a very steep slope, called the shelf break.
• Continental slope: From the break, the shelf descends toward the deep ocean floor in what is called the continental slope.
• Width: The width of the continental shelves varies from one ocean to another. The average width of continental shelves is about 80 km.
  • Narrow shelves: The shelves are almost absent or very narrow along some of the margins like the coasts of Chile, the west coast of Sumatra, etc.
  • Wide shelves: On the contrary, the Siberian shelf in the Arctic Ocean, the largest in the world, stretches to 1,500 km in width.
• Depth: The depth of the shelves also varies. It may be as shallow as 30 m in some areas while in some areas it is as deep as 600 m.
• Sediment deposition: They are covered with variable thicknesses of sediments brought down by rivers, glaciers, wind, from the land and distributed by waves and currents, becoming the source of fossil fuels.

Legal aspects

• UNCLOS definition: Under the United Nations Convention on the Law of the Sea (UNCLOS), the continental shelf is the seabed and subsoil extending up to 200 nautical miles from a coastal state’s baseline or further if the natural margin extends beyond this limit.
• Sovereign rights: Coastal nations have exclusive rights to explore and exploit resources on their continental shelf.
• Extended Continental Shelf (ECS): Countries can claim beyond 200 nautical miles if they can prove the natural prolongation of their landmass, as India has done in the Arabian Sea and Bay of Bengal.