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
Petermann Orogeny the Cambrian. Sediments are a mixture of fluvial conglomerates, sandstones, and siltstones. Several pull-apart structural grabens formed at flexures in the orogenic belt, forming the Levenger and Moorilyanna Grabens. The Petermann Orogeny is dominated by south-over-north movement on several large, anastomosing curved thrust faults. The prime thrust fault is the Woodroffe Thrust, which is a laminated pseudotachlyte-schist zone up to 300 metres thick. This has accommodated up to 42 kilometres of vertical movement at an angle of about 15 to 20 degrees. The structure of the Petermann Orogen within the Musgrave Block is considered to be a "flower-structure", which is