The Atlantic Ocean was born roughly 200 million years ago when the supercontinent Pangea began to break apart. As continental crust stretched and fractured, oceanic crust took its place. To investigate this rifting process, scientists can analyze the structure of the present-day eastern North American margin, where North America and the Atlantic Ocean meet. The composition of the crust and upper mantle provides clues about geological processes that accompanied continental breakup.
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Source: Phys.org