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
Matterhorn plate, a small continent which broke up from Africa before the Alpine orogeny. For this reason the Matterhorn has been popularized as an African mountain. The Austroalpine nappes are mostly common in the Eastern Alps. The Swiss explorer and geologist Horace-Bénédict de Saussure, inspired by the view of the Matterhorn, anticipated the modern theories of geology: The formation of the Matterhorn (and the whole Alpine range) started with the break-up of the Pangaea continent 200 million years ago into Laurasia (containing Europe) and Gondwana (containing Africa). While the rocks constituting the nearby Monte Rosa remained in Laurasia, the rocks constituting