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How did the Atlantic Ocean form during Pangea’s breakup?
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paleogeography
Watch a time-lapse of Earth changing through geologic time, from the Cambrian Era to the projected period of Pangea Proxima.
The formation of the Atlantic Ocean was a multi-stage process driven by plate tectonics following the breakup of the supercontinent Pangea, which began approximately 200 million years ago.12
The process unfolded in several key phases:
- Initial Rifting: About 230 million years ago, rift faulting began on the eroded surface of the Appalachians. By 200 million years ago, these rifts were flooded by mantle-derived lavas, creating the Central Atlantic Magmatic Province.34
- Seafloor Spreading: True oceanic basin formation began between 180 and 160 million years ago as seafloor spreading commenced in the proto-Atlantic, separating North America from Africa.13
- South Atlantic Opening: The South Atlantic Ocean began to open approximately 140 million years ago as Africa and South America drifted apart.24
- Continued Expansion: The Atlantic basin continues to widen today due to the Mid-Atlantic Ridge, a rift zone where magma rises from the mantle to form new crust, pushing the continents further apart at an average rate of about 1 inch (2.5 cm) per year.1