Sevier orogeny Sevier orogeny The Sevier orogeny was a mountain-building event that affected western North America from Canada to the north to Mexico to the south. The Sevier orogeny was the result of convergent boundary tectonic activity between approximately 140 million years (Ma) ago and 50 Ma. The Sevier River area of central Utah is the namesake of this event. This orogeny was produced by the subduction of the oceanic Farallon Plate underneath the continental North American Plate. Crustal thickening that led to mountain building was caused by a combination of compressive forces and conductive heating initiated by subduction in the Sevier
Trans-Hudson orogeny valley that continued to spread until it resulted in a passive margin in which there was no tectonic activity. Shallow marine deposits formed on the continental shelves, and oceanic crust formed on the margins of the continental cratons as the divergence continued. Eventually the divergence stopped, then reversed direction, and collision occurred between continental land masses. During the Wopmay orogeny, subduction occurred as oceanic crust of the Slave Craton was subducted beneath an eastward moving continental plate. Likewise, during the Trans-Hudson orogeny, rifting at first separated the Superior craton from the rest of the continent. Then the Superior Craton reversed