Why are continents so much older than the ocean basins?
Why are continents so much older than the ocean basins?
Continents are the portions of land which are not covered with ocean water. About 260 million years old crust is found under the oceans. But this crust is much younger than the continental crust, which is about 4.3 billion years old.
The oceanic crust is younger because subduction leads to the sinking of older oceanic crust in the asthenosphere, a part of the upper mantle. The subduction process does the recycling of the older plate, and it comes to the surface again from the mid-oceanic ridge. The continental crust do not subduct because the oceanic crust is denser than it. So, oceanic crust only gets subducted. Therefore, continents are much older than the ocean basins.
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