Alleghanian orogeny Alleghanian orogeny The Alleghanian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H.P. Woodward in 1957. The Alleghanian orogeny occurred approximately 325 million to 260 million years ago over at least five deformation events in the Carboniferous to Permian period. The orogeny was caused by Africa colliding with North America. At the time, these continents did not exist in their current forms: North America was part of the Euramerica super-continent, while Africa was part of Gondwana. This collision formed
Gondwanide orogeny orogeny is the successor to the Neoproterozoic-Paleozoic Terra Australis orogeny in Gondwana. Following the Gondwanide orogeny southwestern Gondwana entered a period of extensional tectonics and crustal thinning leading to formation of various rift basins (e.g. Cuyo Basin) in the Triassic. Gondwanide orogeny The Gondwanide orogeny was a orogeny active in the Permian that affected parts of Gondwana that are by current geography now located in southern South America, South Africa, Antarctica, Australia and New Guinea. The zone of deformation in Argentina extends as a belt south and west of the cratonic nucleus of Río de la Plata–Pampia. The deformation of