Arizona Gold Production Summary
The gold deposits of Arizona are of several types. In the San Francisco and Kofa districts gold deposits occur in epithermal quartz-calcite veins of Tertiary age. The Weaver, Vulture, Harquahala, Gila City, Wallapai, and Dos Cabezas districts are representatives of mesothermal vein systems of Mesozoic or Tertiary age with sulfide-quartz veins rich in silver and gold. In the porphyry copper deposits—in the districts of Ajo, Bisbee, Clifton-Morenci, Globe-Miami, Ray, San Manuel, and Superior—the ore bodies are of late Mesozoic or Tertiary age and are in intrusive bodies of quartz monzonite and the adjacent country rocks. The porphyry copper deposit at Jerome is of Precambrian age. Replacement deposits, rich in gold, silver, and base metals, occur near granitic intrusives in the Tombstone, Big Bug, Turquoise, Banner, and Agua Fria districts.