GEOLOGY
The lithostratigraphic units in the area include plutonic, volcanic, and sedimentary rocks ranging in age from the Upper Cretaceous to the Recent. The Upper Cretaceous is represented by the Tarahumara Formation (Wilson and Rocha, 1946), and consists of andesite, agglomerate, andesitic tuff with some horizons of sandstone, limestone and rock acidic such as trachyte, trachyandesite and dacite. These units form part of the volcanic and volcano-sedimentary sequences that make up the Western Sierra Madre volcanic complex.
From the Upper Cretaceous to the Oligocene, these pre-existing rocks were intruded by plutonic bodies of granitic, granodioritic, and dioritic composition.
The Miocene Middle is represented by conglomerate-sandstone and conglomerate-rhyolitic tuff of the Báucarit Formation (King, 1939), these rocks represent a sedimentation linked to the Tertiary distension of the Basin and Range and are represented by polymictic conglomerate and sandstone filling tertiary basins concordantly overlying the Báucarit Formation are flows of rhyolitic tuff, andesite, latite, basaltic andesite, basalt and tuffaceous sandstones, Miocene age of the Lista Blanca Formation (Dumble, 1900).
During the Pleistocene, poorly consolidated detrital conglomerates were deposited, consisting of polymictic material. In the Recent period, slope and alluvial sediments, including gravel, sand, and silt were deposited across the area
