Theory question 205
Oceans and Lakes(a) Draw an annotated diagram to show the relief of the ocean basin (b) Describe the characteristics of any two of the relief features shown on your diagram
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(a) Cross-section from land to deep ocean labelled: continental shelf, continental edge, continental slope, deep sea (abyssal) plain, ocean ridge, ocean deep/trench; sea level shown.
(b) e.g. Continental shelf: gently sloping shallow sea floor bordering continents, depth up to about 180 m; width varies; rich fishing grounds (plankton, sunlight); oil and gas deposits.
Continental slope: steep slope from the shelf edge down to about 3,000-4,000 m; cut by submarine canyons.
Deep sea plain: wide, flat floor at about 3,000-6,000 m covered with oozes and red clay.
Ocean deep/trench: long narrow very deep troughs (e.g. Mariana Trench about 11,000 m), near island arcs.
Label the features in the correct order from the coast.