Introduction
The South Mountains, located directly south of Phoenix, are a metamorphic core complex composed of intrusive and metamorphic rocks that were formed in the deep crust, and then raised tectonically to upper crustal depths. Uplift occurred during a time of extensional stress, when rocks in the South Mountains were extended in a northeasterly direction. Joints within a Tertiary granite strike NNW, indicating an extensional environment with ?3 oriented horizontal and ENE. Striated faults similarly record a NE orientation of ?3 and vertical ?1.