Opening of the North Atlantic Ocean

The opening of the North Atlantic Ocean is a geological event that has occurred over millions of years, during which the supercontinent Pangea broke up.

[2] The supercontinent known as Pangea existed during the late Paleozoic and early Mesozoic eras and began to rift around 200 million years ago.

[7] Since these rocks have been dated to the late Paleocene, this lines up with the time of breakup of the North Atlantic continent, so some think it could have been a contributing factor.

[6][8] Volcanism thus occurs where the crust is easier to break up because it has been stretched by lithospheric extension, allowing melt to reach the surface.

The upward flow of the asthenosphere results in decompression melting, magmatic underplating and some volcanism that may occur in the rift area.

Opening of Central and North Atlantic from 170 Ma to the present
Animation of the rifting of the supercontinent Pangea
Plume hypothesis for continental breakup. Active upwelling heats and weakens crust and creates magmatism.