Miscanti and Miniques occupy fault-bound basins, which are controlled by the Quebrada Nacimiento fault; the fault is also known as the Miscanti Fault and is part of a detachment fault system east of the Salar de Atacama, which separates the Western Cordillera from the Cordillera Domeyko. This fault extends from the Purico complex, Llano de Chajnantor to Cerro Miniques and has formed a ridge, which has dammed lava flows from Cerro Miscanti and Cerro Miniques. The basins developed during the Pliocene and Pleistocene; Laguna Lejia also developed along this fault and the fault segment there is also known as Miscanti-Callejon de Varela fault. Volcanoes including Lascar are constructed on this fault, and the Cerros Saltar and Corona north and south of Lascar are lined up on it as well.