Abyssal Plain

Abyssal Plain

 

  • Abyssal plains are extremely flat and featureless plains of the deep ocean floor.
  • In fact, the abyssal plains are likely the most level areas on the earth.
  • Abyssal plains covering a major portion of ocean floor between the depth of 3000m to 6000m.
  • They were once regarded as featureless plains but modem devices have shown that they are as irregular as the continental plain or surface.
  • They have extensive submarine plateaus, hills, guyots and seamounts.
  • The floor of the abyssal plain is covered by sediments.
  • The plains close to the continents are covered mostly by sediments brought down from the land.
  • But those seas which favour, an abundant growth of organisms have a thick layer of sediments, formed from the remains of living things.
  • These sediments are called
  • Some of the open seas do not support enough life to produce ooze on the floor.
  • They are covered with a type of sediment called red clay which is of volcanic origin or made up of tiny particles brought by wind and rivers.

 

Submarine Ridges

 

Submarine Ridges

  • The lofty mountain systems which exist on the continents are also represented beneath the ocean waters.
  • These oceanic mountains are known as submarine ridges.
  • They are linear belts occurring near the middle of the oceans and are also called mid-oceanic ridges.
  • All the mid oceanic ridges constitute a world-wide system which is interconnected from ocean to ocean.
  • These ridges are intersected by faults.
  • The oceanic ridge is the site of frequent earthquakes.
  • Volcanism is common in ocean ridges and it produces many relief features.
  • The Mid-Atlantic Ridge is the largest continuous submerged mountain ridge which runs from north to south in the Atlantic-Ocean.
  • It is in the shape of S. At some places, the peaks, rise above the surface of water in the form of islands.
  • Many of the islands are volcanic in origin. The East Pacific Ridge and Carlsberg Ridge are some of the important submarine ridges.

 

 

Seamounts and Guyots

  • Scattered over the entire sea floor are thousands of submerged volcanoes with sharp tops called seamounts.
  • Sometimes they rise above the sea as isolated Islands.
  • Hawaii and Tahiti Islands are the exposed tops of volcanoes.
  • Volcano rising above the ocean floor whose top has been flattened by erosion and is covered by water is called guyot.