Geology, Mines, & Minerals, Tombstone, Arizona
Geology, Mines, & Minerals, Tombstone, Arizona by Jan C. Rasmussen Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Acknowledgements • SRK Consulting, Tucson • Burton Devere – Bonanzas to Borrascas • Peter Megaw – photomicrograph specimens • Sugar White – photography of Megaw specimens • TGMS 2012 show displays • Mindat.org • Jim Briscoe Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Location: Cochise Co., SE Arizona Source: SRK Consulting Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Geologic map, Cochise County Source: AZGS map 35 Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Geologic map, Tombstone Hills Source: Drewes, USGS geologic map Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Gilluly geologic map Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Tombstone Hills, looking north Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Paleozoic Jan and Colina Limestone (Permian) Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Bisbee Group – Lower Cretaceous Jan Rasmussen Geology, Mines, Minerals of Tombstone April 14, 2012 Laramide orogeny Orogenic Age Phase (Ma) Sedimentation Magmatism Structures Resources widespread, 2-mica, garnet- muscovite granitoid stocks, SW-directed, low-angle thrusts mesothermal, Pb-Zn-Ag veins, minor batholithic sills, aplo-pegmatite widespread, shallowly dipping mylonitic Cu-Au veins, Au in quartz veins, Late 55-43 none dikes, peraluminous, calc-alkalic zones,
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