The gneissic texture encountered in the Proterozoic Oracle Granite exposed in the Santa Catalina Mountains developed under high pressure and temperature conditions in Earth's crust. Rock of the Santa Catalina's are the exposed as the result of extension, uplift, and erosion during the onset of Arizona's Basin and Range activity.
Photographer: Spencer, Jon
Photo Date: circa 2015
Photo Location Accuracy: Approximately Located
Photo Tags: Oracle Granite, GSA2019, Arizona Rocks, Santa Catalina Mountains, Tucson, metamorphic core complex