Hot spot activity and the break-up of Pangea

Abstract

The Mesozoic and Cenozoic positions of the continents that formed Pangea in the Triassic–Jurassic were derived from paleomagnetic and intraplate volcanic data, paleoclimatic observations, such as reef and fossil flora distribution, and geological observations. Major hot spots helped to determine the longitudinal position of Pangea and to construct a model of plate motion during the Pangean break-up. The position of the northern part of Pangea was constrained using Iceland and Jan Mayen hot spots. The Iceland hot spot was traced from its present day position to Greenland in the Paleocene, to Baffin Bay in the Late Cretaceous, to the Alpha Ridge in the Early Cretaceous, to the Chukchi Borderland in the Middle–Late Jurassic, to Franz Joseph Land in the Early Jurassic, the Yenisei–Khatanga Trough in the Middle Triassic, and finally to West Siberia in the Late Permian–Early Triassic. The hot spot activity is expressed by Eastern and Western Greenland volcanics, the Siberian trap basalts, and perhaps by Alpha Ridge and Chukchi Borderland volcanics. The Chukchi Borderland volcanics are related to the early stage of the opening of the Canadian Basin. The position of the southern part of Pangea was constrained using the Bouvet hot spot. This hot spot was tracked from its present day position to Western Antarctica in the Early Cretaceous–Late Jurassic and to South Africa in the Early Jurassic–Late Triassic. This hot spot activity produced the Ferrar and Karoo volcanics. The model of plate motion obtained agrees with other data on intraplate volcanics, which are also related to hot spots. At the time of the opening of the Central Atlantic, the Cape Verde and Canary Island hot spots were located along the ocean's spreading axis. The long lasting location of hot spot and associated mantle upwelling plumes could help to explain forces driving the Tethys transit plates, opening of the Ligurian Ocean and Eastern Mediterranean. The European hot spots are related to the several Mesozoic phases of rifting. For example, the Rhine Graben hot spot may have been located at the rifting axis in the North Sea. Several authors have already discussed the contribution of hot spots to the opening of the South Atlantic and Indian oceans. Mantle plumes associated with hot spots play an active role in rifting and initial phases of spreading. The lithospheric displacement, caused by upwelling combined with sometimes remote collisional forces on the other side of continental plate, may result in compression and basin inversion.