Reconstruction of Pangaea: Breakup and dispersion of continents, Permian to Present

Authors

  • Robert S. Dietz,

  • John C. Holden


Abstract

We present a new continental drift reconstruction of the universal continent of Pangaea in the Permian plus a series of five world maps to depict the breakup and dispersion of continents with each subsequent geologic period, Triassic to Recent. Plate tectonics and sea-floor spreading are accepted as the guiding rationale. Also utilized are the morphologic fitting of continental margins and paleomagnetic pole positions. Rigor is imposed by the geometric requirements involved in presenting continental drift dispersion on maps in orderly time sequence and by following certain assumed rules of plate tectonics. The reconstructions were first made on a globe and then transferred to an Aitoff world projection. In the Permian, the Atlantic and Indian oceans were closed so that all the continents were configured into the universal landmass of Pangaea. The reconstruction is based largely on the morphologic best fit of continental margins to the 1000-fathom isobath, except for India, the east coast of which is placed against Antarctica, as dictated by plate tectonics. In the Triassic the breakup of Pangaea commenced. The southwest Indian Ocean rift was created, which split West Gondwana (South America and Africa) away from East Gondwana while a Y junction lifted India off Antarctica. An independent North Atlantic–Caribbean rift also formed, which lifted Laurasia (North America and Eurasia) off of South America and the bulge of Africa. In the Jurassic, northward and westward sea-floor spreading further opened the central North Atlantic and the Indian oceans. At the end of the period, a new rift incipiently split South America away from Africa. The Walvis mantle thermal center or ‘hot spot’ formed, which would subsequently provide an absolute geographic reference point for subsequent continental drift. In the Cretaceous, the motions already established continued. The North Atlantic rift grew northward, blocking out the Grand Banks and the western margin of Greenland. Spain rotated sinistrally, forming the Bay of Biscay. An offshoot rift split Madagascar from Africa, dropping off this subcontinent from Africa, which continued its northern flight. The northward trek of India continued, and Australia incipiently split away from Antarctica. During the Cenozoic, Antarctica rotated further westward. Australia experienced a remarkable flight northward, and New Zealand was split away from its east coast. The North and South Atlantic oceans continued to open; the rift that formerly passed west of Greenland now switched to the east and split Greenland away from northern Europe and extended through the Arctic Ocean. Africa moved slightly northward, continuing sinistral rotation. The Tethyan megashear became dextral for the first time, India collided with and underran Asia.

Ancillary