OROGENY

mountain-building event, generally one that occurs in geosynclinal areas. In contrast to epeirogeny, an orogeny tends to occur during a relatively short time in linear belts and results in intensive deformation. Orogeny is usually accompanied by folding and faulting of strata, development of angular unconformities, and the deposition of clastic wedges of sediments in areas adjacent to the orogenic belt. Igneous intrusion and regional metamorphism are often associated with an orogenic event as well. Orogenies may result from continental collisions, the underthrusting of continents by oceanic plates, continental rifting, the overriding of oceanic ridges by continents, and other causes. Compare epeirogeny.