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
Grenville orogeny the Highlands to the southeast and the Lowlands to the northwest. It is believed that the shear zone (the Carthage-Colton) was a transpressional boundary during the Ottawan, when the Highlands were thrust over the Lowlands. The Grenville province is named for the village of Grenville in Quebec, and constitutes the youngest portion of the Canadian Shield. Since the area has not undergone any regional metamorphic overprinting since the orogeny, it is considered an ideal study area for Grenville and pre-Grenville age tectonics. Hence, most of what is known about the orogeny and its processes is derived from the Grenville Province.