Andean orogeny Andean orogeny The Andean orogeny () is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system along the western margin of South America. On a continental scale the Cretaceous (90 Ma) and Oligocene (30 Ma) were periods of re-arrangements in the orogeny. Locally the details of the nature of the orogeny varies depending on the segment and the geological period considered. Subduction orogeny has been occurring in what is now western South America since the break-up
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