Question

what are oceanic or submarine plateaus​

Answer 1

Oceanic plateau, also called Submarine Plateau, large submarine elevation rising sharply at least 200 m (660 feet) above the surrounding deep-sea floor and characterized principally by an extensive, relatively flat or gently tilted summit. Most oceanic plateaus were named early in the 20th century prior to the invention of sonic sounding, and many of these features have been shown by modern bathymetric data to be portions of the oceanic ridges. Thus, the Albatross Plateau of the eastern equatorial Pacific now is recognized as belonging to the East Pacific Rise and has been shown to possess a much more irregular summit than early data indicated.