How can continental drift create isolated plateaus in the ocean?

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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.

Isolated plateaus found in the deep ocean are believed to be minor fragments of continent that have been separated from larger landmasses. These features, such as the coral-capped plateaus of the South China Sea, stand as topographic highs above the surrounding seafloor and are composed of continental rock cores covered by marine sediments.1

The creation of these isolated plateaus is attributed to the processes of continental drift and seafloor spreading. As tectonic plates move and diverge, fragments of continental crust can become detached and stranded within the oceanic domain. Unlike the oceanic crust, which is dense and thin, these continental fragments are thicker and more buoyant, allowing them to persist as elevated features even when surrounded by the deep-sea floor.12