Write short notes on the following :

4.  Continental slope, Abyssal Plains.

 Continental Slope : It is an area of steep slope extending just after the continental shelf upto a considerable depth from where a gentle sea plain takes its form. The extent of the slope area is usually between 200-2000 metres depth. But sometimes it may extend to 36000 metres from the mean sea level. The continental slope along many coasts of the world is furrowed by deep canyon-like trenches. Continental slope covers 8.5 per cent of the total ocean area.

There are five types of slopes :

(i) Fairly steep with the surface dissected by canyons.

(ii) Gentle slope with elongated hills and basins.

(iii) Faulted slopes.

(iv) Slopes with terraces and

(v) Slopes with sea mounts.

The Abyssal Plains : Beyond the continental slope are the Abyssal Plains. They are located at a depth of 3000 to 6000 metres. They cover about 40% of the ocean floor. The deposits of fine matter containing bones and shells of minute animals that live and die on the surface of sea are found. They are found in all the major oceans of the world.

Fig. 13.7 : Submarine features and their depths