Breakup of Pangea and the Cretaceous Revolution

作者：Xavier Le Pichon, A. M. Celâl Şengör, M. Jellinek, A. Lenardic, Caner İmren · 发表于：Tectonics · 年份：2023 · DOI：10.1029/2022tc007489 · 被引用次数：21 · 研究领域：Geological and Geochemical Analysis、High-pressure geophysics and materials、Paleontology and Stratigraphy of Fossils

Abstract A 250 Ma, Pangea had just reached an equatorial position of dynamic equilibrium, after a 60° northward migration due to True Polar Wandering. It then began oscillating about itself for the next 150 Myr. The resulting extensional stresses triggered three successive phases of breakup, controlled by the mechanical resistance of a crescent of thick lithosphere, surrounding the Tethyan realm, which had adjusted the supercontinent to its hemispheric shape. The fracturing of the crescent was produced in three successive generations, each new generation corresponding to Coulomb fractures, conjugates of the preceding set. Flood basalts were associated with these deep fractures within the thick lithosphere crescent. We consider unlikely that this highly ordered pattern of fracturing was determined by the locations of the impacts of successive plumes. Between 260 and 180 Ma, thermal isolation was maximal and the asthenosphere of Pangea was about 150°C warmer than below Panthalassa. From 180 to 100 Ma, the breakup elongated Pangea by about 3,000 km in a north‐northwest–south‐southeast direction, producing gaps in the subduction girdle. Lateral mixing began, leading to a continuous rise in global sea level and progressive return to a globally homogeneous upper mantle with sea‐level at its maximum 100 Ma. This Cretaceous Revolution marked the end of the Pangea tectonics, radically different from our present plate tectonics. Neither post‐Cretaceous plate kinematic inferences, nor m...