Metamorphic core complexs are characteristically areas of exposed mylonitic rocks that were exhumed by large displacement on gently to moderately dipping normal faults. Arizona hosts a number of core complexes that formed during Olig-Miocene extension associated with early Basin and Range development.
Online Resources authored by Jon Spencer: A geologist's guide to the core complex geology along the Catalina Highway, Tucson Area, Arizona; http://repository.azgs.az.gov/uri_gin/azgs/dlio/360 Graphics for core-complex morphology and geologic continuous casting; http://repository.azgs.az.gov/uri_gin/azgs/dlio/115
