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
Pampean orogeny Pampean orogeny The Pampean orogeny () was an orogeny active in the Cambrian in the western margin of the ancient landmass of Gondwana. The orogens remains can now be observed in central Argentina, in particular at the Sierras de Córdoba and other parts of the eastern Sierras Pampeanas. It is uncertain if the orogeny involved at some point a continental collision. The Pampean orogen can be considered both part of the larger Terra Australis orogen and of the Brasiliano orogeny. The Pampean orogeny was succeeded by the Famatinian orogeny further west. The Pampean orogen contains a magmatic belt including granodiorites,