a relatively short period, or phase, of increased activity of tectonic motions in geologic history. Such periods last for a few million years.
Orogenic epochs manifest themselves in the intensive development of orogenic disturbances, including upwarping, downwarping, and, especially, folding and faulting. Magmatism and regional metamorphism often accompany the epochs. Many orogenic epochs are named after the regions where they were established. For example, the Sudetic, which lasted from the end of the early Carboniferous to the beginning of the middle Carboniferous, takes its name from the mountains known as the Sudetes. The Laramide, which lasted from the end of the Cretaceous to the beginning of the Paleogene, is named after the Laramie Mountains, which are a range of the Rockies in the USA. (See also.)