When and how were the Alps formed?
The Alps were formed when the African and the Eurasian Plates collided. (Pangaea)
The Alps are a complex fold-mountain system. Sedimentary deposits of vast thickness, mainly limestone and dolomite, were laid down in the ancestral Tethys Sea during the Triassic and Jurassic periods. Subsequently, enormous pressure generated by a collision between the African and Eurasian plates (see Plate Tectonics) thrust these rock strata upward and northward to form recumbent folds (nappes), which in the process of movement were detached from their roots. The four glaciations of the Quaternary period (beginning about 2.5 million years ago) were of great importance in the sculpturing of the Alps. Vast ice masses moved through the valleys, transforming them into deep troughs with steep walls; the overflow of ice across the mountain divides shaped the passes.
