Break-up of Pangaea and Mesozoic tectonic evolution of the Mediterranean region

A new Pangaea fit (type A) is proposed for the late Ladinian (230 Ma) together with a plate motion model of the break-up of Pangaea from middle Triassic to chron M25. This model is based upon: a) an interpretation of the mechanism of formation of the East Coast and Blake Spur Magnetic Anomalies along the eastern margin of North America, and the Sl magnetic anomalies along the conjugate margins of northwest Africa and the Moroccan Meseta; b) an analysis of major rifting events in the central Atlantic, Atlas and central Mediterranean- c) a crustal balancing of the stretched margins of North America, Moroccan Meseta and northwest Africa; and d) a new apparent polar wander path of Africa since middle Triassic. The model of Pangaea break-up between the late Ladinian (230 Ma) and the oldest identified oceanic magnetic anomaly (M25 154.3 Ma) considers three stages. During the first stage, from the late Ladinian (230 Ma) to the middle Norian (210 Ma), Morocco was fixed with respect to North America, whereas rifting proceeded along the eastern margin of N. America, the northwest African margin, the High, Saharan and Tunisian Atlas, and in the central Mediterranean. During the second stage, from the middle Norian (210 Ma) to the late Pliensbachian (185 Ma), the Morrocan Meseta separated from North America and left-lateral transcurrent motion occurred along the Middle Atlas, which acted as a transform plate boundary between the Moroccan Meseta and eastern Morocco. Finally, during the third stage from the late Pliensbachian (185 Ma) to chron M25 (154.3 Ma) the main plate boundary jumped northward between Morocco and Iberia, whereas no motion occurred along the Atlas fault systems. A set of plate tectonic reconstructions and an animation are proposed to illustrate the changing configuration of the continents during the break-up of Pangea.