Phanerozoic continental drift
Abstract An account is given of Phanerozoic continental drift. A series of paleocontinental maps is presented for ten intervals from 600 to 25 My ago. Post-Triassic maps were reconstructed using the plate-tectonic model, based mainly on ocean-floor spreading evidence, continental edge fits and apparent polar wander (APW) paths. The middle Carboniferous-Triassic maps are less certain, lacking ocean-floor spreading evidence, but continental positions are constrained by the assumptions of minimum relative continental motions. The pre-Carboniferous maps are based on poorly-defined APW paths and minimum motions, and can only indicate probable configurations during that period. The main theme is that the late Precambrian “Pan-African” Pangea has been progressively fragmented during the Phanerozoic. Pieces broken-off in the Paleozoic have now collided with one another forming the present northern continents, which have grown at the expense of Pangea. Except for India, fragments broken-off in the Mesozoic and Cenozoic are still unattached and form the present southern continents.