Orogeny Orogen" resulted from these events and various others that are part of its peculiar orogenic cycle. In summary, an orogeny is an episode of deformation, metamorphism and magmatism at convergent plate margins, during which many geological processes play a role at convergent plate margins. Every orogeny has its own orogenic cycle, but composite orogenesis is common at convergent plate margins. Erosion represents a subsequent phase of the orogenic cycle. Erosion inevitably removes much of the mountains, exposing the core or "mountain roots" (metamorphic rocks brought to the surface from a depth of several kilometres). Isostatic movements may help such exhumation
Antler orogeny some of the classic features of orogeny as commonly defined such as metamorphism, and granitic intrusives have not been linked to it. In spite of this, the event is universally designated as an orogeny and that practice is continued here. This article outlines what is known and unknown about the Antler orogeny and describes three current theories regarding its nature and origin. There are two principal facies of lower Paleozoic rocks in Nevada. In the eastern part of the state, a north-trending fossil-rich carbonate shelf of Ordovician to Devonian age, termed the carbonate or eastern assemblage, gives way westward to