Panthalassa

Panthalassa was the vast global ocean that surrounded Pangaea during much of the Paleozoic and Mesozoic eras. Its contraction accompanied the opening of the Atlantic Ocean.

Pangaea: A supercontinent that assembled during the late Paleozoic and began breaking apart in the Mesozoic. Its assembly brought the continents together within Panthalassa; its breakup reshaped the ocean.
Subduction: The descent of one tectonic plate beneath another into Earth's mantle. Subduction around Panthalassa consumed oceanic crust along extensive convergent margins.
Paleozoic: The geologic era from about 541 to 252 million years ago, preceding the Mesozoic. Panthalassa existed through much of this era as continents converged into Pangaea.
Wrangellia: A large oceanic plateau and terrane whose volcanic rocks formed in the Paleozoic and Mesozoic Pacific realm. Its ancient volcanic record offers evidence from Panthalassa's oceanic domain.
Plate tectonics: The theory that Earth's lithosphere consists of moving plates whose interactions shape continents and ocean basins. Plate motions explain Panthalassa's changing boundaries and eventual disappearance.
Mid-ocean ridge: An underwater mountain chain where tectonic plates diverge and new oceanic crust forms. Ridge systems generated crust that spread across Panthalassa's enormous seafloor.
Mesozoic: The geologic era from about 252 to 66 million years ago, encompassing the Triassic, Jurassic, and Cretaceous periods. Pangaea's breakup during this era began the ocean-basin changes that ended Panthalassa.
Siberian Traps: A vast province of flood-basalt volcanism in Siberia associated with the end-Permian mass extinction. The extinction devastated marine ecosystems inhabiting Panthalassa as well as other oceans.
Pangaea Ultima: A proposed future supercontinent that could form if continental convergence continues. It offers a speculative comparison for how a future global ocean might be reorganized.
Oceanic crust: The relatively thin, dense outer layer of Earth beneath ocean basins, composed mainly of basaltic rocks. Its production and destruction determined how Panthalassa's seafloor changed.

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