Mesozoic Epochs of Folding

epochs of intensive manifestations of folding, mountain building, and granitoid intrusive magmatism, occurring during the Mesozoic era. These epochs were most intensive along the periphery of the Pacific Ocean (in East Asia, the Cordilleras, and the Andes) where they are called the Pacific Ocean orogeny.

The initial tectonic epoch of the Mesozoic era, the early Cimmerian or Indochina epoch, dates to the end of the Triassic and beginning of the Jurassic. Its manifestations are found in Indochina, in the northeastern part of the Iranian Plateau, on the Mangyshlak and Taimyr peninsulas, in northern Dobruja, and some regions of the North American Cordilleras. After the early Cimmerian came the late Cimmerian tectonic epoch, which is also known as the Andean, Nevadian, Kolymian, and Araucanian; it was the main epoch of formation of the structures in the Verkhoiansk-Chukchi region, the Mongolian-Okhotsk folded system, the central part of the North and South American Cordilleras, and several other regions. The epoch manifested itself in the late. Jurassic and early Cretaceous. New tectonic movements occurred in the middle and especially at the end of the Cretaceous and beginning of the Paleogene. This was the Laramide epoch, when the structure of the Rocky Mountains, the western part of the Koriak Mountains, the Kamchatka Peninsula, the Sikhote-Alin’, and the island of Sumatra was formed.

Outside the geosynclinal systems Mesozoic tectogenesis manifested itself in uplifts in the marginal parts of the platforms (especially the Siberian and South China platforms) and a renewal of magmatic activity (acidic volcanism, intrusions of granitoids in East Asia). Mesozoic tectogenesis was accompanied by the formation of numerous deposits of nonferrous metals (copper, molybdenum, tin, tungsten) and gold deposits (the Pacific Ocean belt, the Mongolian-Okhotsk system, the activated parts of the surrounding platforms and, partially, the Mediterranean zone). Some investigators combine the Mesozoic epochs of folding and the Alpine epoch of folding proper into one Alpine cycle of tectogenesis.