Sevier orogeny east. In contrast, the Laramide orogeny produced “basement-cored” uplifts that often took advantage of pre-existing faults that formed during rifting in the Late Precambrian during the breakup of the supercontinent Rodinia or during the Ancestral Rocky Mountains orogeny. The Sevier orogenic belt consisted of a series of thin plates along gently dipping west thrust sheets and moving from west to east. These thin skinned thrusts moved late Precambrian to Mesozoic age rock of the Cordilleran passive margin east. The Sevier meets the Laramide orogenic belt on its eastern side. The Sevier and Laramide combination is similar to the modern day
Nevadan orogeny deformation from the Nevadan Orogeny in the Eastern Belt is somewhat limited. It was determined that the deformation was minimal in the Eastern Belt by looking at dikes that had intruded the rocks which appeared to be mostly undeformed. These mostly undeformed dikes were dated using the K-Ar method and were determined to be between 169 and 209 Ma in age, which implies they were placed well before any deformation related to the Nevadan Orogeny would have occurred. As the age of these dikes are older than the deformation of the Nevadan Orogeny, it is evident that most of the