Porphyry copper exploration of the Hualapai Mountains, Mohave County, Arizona, USA: A multi-faceted approach

A variety of exploration methods including geologic mapping, trace- and major-level geochemical analyses, fluid inclusion petrography, remote sensing, and SWIR clay spectroscopy were used to investigate the potential for porphyry Cu-Mo mineralization at the Wikieup prospect, in the southern Hualapai Mountains of northwestern Arizona. Aspects of the Mineral Park mine were used as an analogue to guide exploration due to the proximity and similar geology of the area.;The Hualapai Mountains are a series of northwest-trending Precambrian gneisses, schists, granitoids and amphibolites that have been cut by younger intrusive rocks. Within the Wikieup study area, the intrusive rocks include aplite dikes that are crosscut by a younger set of rhyolite dikes, and the youngest porphyry dikes which crosscut both the aplite and the rhyolite. Mineralized quartz veins are commonly associated with the Precambrian-porphyry contact.;Mineralized quartz vein samples were collected from historic mines, prospecting pits, and outcropping quartz veins throughout the Wikieup prospect and the adjacent areas. Samples were analyzed by ICP-MS for 51 elements including Mo, Cu, Pb, Zn, Ag, Au, and Mn. A geochemical zonation pattern similar to that of the mining district of Mineral Park was observed, with Au-Ag rich areas in the middle of Wikieup study area and Pb-Zn rich areas in the southern parts of the prospect. Two areas known as Devil's Canyon and Wikieup Queen were identified as Cu-Mo anomaly centers to the south. A Mn halo was detected around Devil's Canyon.;SWIR spectral data collected with the TerraSpec were evaluated to identify clay mineralogy. Results show the presence of AlOH minerals such as illite, kaolinite, and sericite within the Cu-Mo anomalies, and patterns of white mica crystallinity and composition indicate strong alteration near the Cu-Mo anomalies.;Fluid inclusion petrography revealed a zonation of fluid inclusions from north to south across the study area. Fluid inclusion assemblages associated with Au-Ag mineralization in the middle of the Wikieup study area contained irregularly shaped, two-phase inclusions and smaller two-phase, regularly-shaped, liquid-rich inclusions. Two-phase, regularly-shaped, liquid-rich fluid inclusions were observed associated with the Pb-Zn metal zone. Fluid inclusion assemblages from the Cu-Mo centers to the south of the claims contain three- and four-phase halite bearing, regularly-shaped inclusions with an occasional daughter crystal coexisting with vapor-rich, two-phase inclusions, indicating fluid immiscibility.;Band ratio transformation analysis of ASTER Level-1B satellite images provided additional information regarding the zoning of alteration minerals. Surface reflectance absorption features at 2.20 microm and 2.26 microm reveal the presence of Al hydroxide minerals such as illite, kaolinite, sericite, and muscovite, and Fe hydroxide minerals such as jarosite within the Devil's Canyon and Wikieup Queen areas. This zone of alteration continues south into an unmapped area of Bronco Wash.;Results of these studies indicate that the area south of the Can-Cal claims has the greatest potential for porphyry copper mineralization. The original Can-Cal claims are consistent with the fringes of porphyry copper mineralization where hydrothermal conditions where cooler.