Superoceans

Superoceans are vast oceans that, at certain times in Earth history, surrounded a supercontinent. The term emphasizes the global scale of the ocean, contrasting with regional seas and marginal basins. The most widely cited example is Panthalassa, the vast ocean that surrounded the supercontinent Pangaea during the late Paleozoic and early Mesozoic eras (roughly 540 to 180 million years ago). Panthalassa encompassed a large, continuous ocean basin with smaller seas along its rim; its waters interacted with tectonic processes linked to Pangaea's assembly and subsequent breakup.

As Pangaea began to rift in the Late Triassic and Early Jurassic, Panthalassa remained the central ocean while new basins formed as continents split. By the Middle Jurassic to Early Cretaceous, the modern Pacific Ocean began to emerge as the dominant remnant of Panthalassa, while many smaller oceans and seas closed or disappeared. In this sense, the Pacific is sometimes described as the successor to Panthalassa, though plate tectonics have continually reshaped Earth's surface.

In paleogeographic reconstructions, the concept of a superocean helps explain patterns of marine circulation, climate, and biogeography across vast geologic timescales. While Panthalassa is the best-known example, other epochs featured large oceanic basins bounded by shifting landmasses, which some researchers also term superoceans. The term is not universally standardized and is used mainly in historical and explanatory contexts rather than as a formal, current ocean label.