DESCRIPTION OF GEOLOGY, ORE MINERALOGY, AND SOURCE CONSTRAINTS OF MINERALIZING FLUIDS, LITTLE GIANT MINE, YAVAPAI COUNTY, ARIZONA

Copper and gold mineralization at the Little Giant Mine in central western Arizona has been mined intermittently for more than a century. Despite a long history, the source of mineralizing fluids is not constrained. Three possible sources of ore forming fluids have been identified based on field relationships: 1) fluids from a degassing felsic magma; 2) fluids from degassing mafic intrusions; 3) basinal brines associated with detachment faulting. Field mapping, thin section petrography, fluid inclusion microthermometry, geochemistry and stable isotope data will be used differentiate the possible sources of ore forming fluids. Cross cutting relationships and Ar/Ar geochronology will constrain the timing of mineralization. Understanding the source and timing of mineralization at the Little Giant Mine will aid future development of exploration models in similar physiographic areas.