Metamorphic core complexes in Arizona formed during the Oligocene-Miocene about 25 Ma during a period of ~100% extension in parts of the crust in western North America. This picture illustrates the ductile shear zone along the Catalina Detachment Fault.
Photographer: Janel Day
Photo Date: circa 2012
Photo Location Accuracy: Approximately Located
Photo Tags: Catalina detachment fault, Santa Catalina Mountains, metamorphic core complex, upper plate, lower plage, brittle-ductile deformation, Oligocene, Miocene 
