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How did the Blake Plateau form off the southeastern United States?
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plateau
The Columbia Plateau is uniformly covered with basaltic lava flows and spans an area of about 100,000 square miles in Idaho, Washington, and Oregon.
The Blake Plateau is classified as a marginal plateau, which is a specific type of continental margin. It formed as a downwarped or downfaulted block of a former continental shelf.12
Although the plateau is currently submerged between 700 and 1,000 meters (2,300 to 3,300 feet) below sea level, the crust underlying it is continental in character, despite being relatively thin and covered by flat-lying marine sediments. As a marginal plateau, it retains many features of a standard continental margin system but is situated at a significantly greater depth than a typical shelf.12