Sevier orogeny Sevier thrust faults. The Sevier orogeny was preceded by several other mountain-building events including the Nevadan orogeny, the Sonoman orogeny, and the Antler orogeny, and partially overlapped in time and space with the Laramide orogeny. Since the Sevier and Laramide orogenies occurred at similar times and places, they are sometimes confused. In general the Sevier orogeny defines a more western compressional event that took advantage of weak bedding planes in overlying Paleozoic and Mesozoic sedimentary rock. As the crust was shortened, pressure was transferred eastward along the weak sedimentary layers, producing “thin-skinned” thrust faults that generally get younger to the
Pampean orogeny Belt of the Brasiliano Orogeny, but in difference to the Paraguay Belt that ended up in the interior of Gondwana the Pampean Orogen remained at a continental margin. The orogen eventually ceased activity and was succeeded by the Famatinian orogeny further west. The eastern magmatic belt of the Pampean orogeny is interpreted as the remains of a volcanic arc associated with an east-dipping subduction zone while the western one is thought to represent a younger volcanic arc that developed on what was once the accretionary prism of the orogen. There have been differing views among geologists on the tectonic and