Geological history of Earth with highly seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea. The Mesozoic extended roughly from . After the vigorous convergent plate mountain-building of the late Paleozoic, Mesozoic tectonic deformation was comparatively mild. Nevertheless, the era featured the dramatic rifting of the supercontinent Pangaea. Pangaea gradually split into a northern continent, Laurasia, and a southern continent, Gondwana. This created the passive continental margin that characterizes most of the Atlantic coastline (such as along the U.S. East Coast) today. The Triassic Period extends from about 252.17 ± 0.06 to 201.3 ± 0.2 Ma. During the Triassic, almost all the
Avalonia later phases of the Acadian orogeny. This was happening at around the Equator during the later Carboniferous, forming Pangaea with Avalonia near its centre but partially flooded by shallow sea. In the Jurassic, Pangaea split into Laurasia and Gondwana, with Avalonia as part of Laurasia. In the Cretaceous, Laurasia broke up into North America and Eurasia with Avalonia split between them. Iberia was later rotated away again as the African part of Gondwana strike-slipped past it. This last movement caused the Alpine orogeny including the raising of the Pyrenees during the Miocene and Pliocene. As a result of this, part