A Tectonic Twist: How Gibraltar Could Close the Atlantic Ocean

The Earth’s lithosphere is divided into multiple tectonic plates, which are continuously moving. This movement leads to the formation and fragmentation of supercontinents, alongside the creation, expansion, and eventual shrinking of oceans, a process referred to as the Wilson cycle.

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In the Wilson cycle, when a supercontinent like Pangea is broken up, an interior ocean is formed. In the case of Pangea, the interior ocean is the Atlantic. This ocean has a rift in the middle, and passive margins on the side, which means no seismic or volcanic activity occurs along its shores. Destined to keep expanding, an Atlantic-type ocean will eventually become the exterior ocean of the next supercontinent. Currently, Earth’s exterior ocean is the Pacific. The Pacific also has a rift in the middle, but it is bounded by subduction zones and thus will eventually close. Along its margins, earthquakes and eruptions abound—a pattern known as the ring of fire.