The theory, proposed by Alfred Wegener in 1912, that the present continents were once joined in a single supercontinent and have since slowly drifted apart to their current positions.
- Wegener proposed a single supercontinent, Pangaea, surrounded by a single ocean, Panthalassa; Pangaea later split into Laurasia (north) and Gondwana (south).
- Supporting evidence: the jigsaw fit of coastlines (especially South America and Africa), matching rock types and mountain belts, identical fossils across oceans (such as Glossopteris), and ancient climate and glacial deposits.
- Wegener's weakness was the mechanism; the forces he suggested (tidal and centrifugal) were too weak, so the theory was initially rejected.
- It was later vindicated and absorbed into the modern theory of plate tectonics, with sea-floor spreading (Harry Hess) providing the missing driving mechanism.
- India was part of Gondwana; its northward drift and collision with Eurasia formed the Himalayas.
The Pangaea/Laurasia/Gondwana terms, Wegener's evidence (fit, fossils), and the link forward to plate tectonics are standard physical-geography facts.
Continental drift (Wegener, 1912, lacked a mechanism) is the earlier idea; plate tectonics (modern) supplies the mechanism via sea-floor spreading and moving plates.
Wegener's theory that continents split from Pangaea and drifted apart; later confirmed by plate tectonics.