TIMING AND GENESIS OF MINERALIZATION IN THE SILVER ISLAND MOUNTAINS, WESTERN UTAH

The Silver Island Mountains, located near the Nevada-Utah border in central western North America, preserve a thick sequence of Cambrian to Permian carbonate and siliciclastic units that were intruded by Jurassic and Eocene magmatic bodies, and were deformed by compressional deformation during the Sevier Orogeny in the Jurassic and Cretaceous and transtensional deformation in the Miocene to present day. Additionally, there are multiple reported zones of mineralization in the region with the potential for valuable metals, including tungsten, copper, gold and silver. The purpose of this project was to understand the timing, genesis, composition, and evolution of the mineralization in the map area in order to assess the viability further economic exploration. We accomplished this by mapping rock units, faults, fractures, and chemical alterations in the field. Field mapping included identifying and mapping contacts between Paleozoic units and undated intrusive bodies, as well as identifying and characterizing multiple fault zones. In addition, at least two zones of hydrothermal alteration were identified, mapped, and sampled, one containing visible malachite and another that was dominated by visible hematite and goethite. Samples were analyzed using scanning electron microscopy, X-ray diffraction, and X-ray florescence spectroscopy to determine crystal structures, mineral relationships and chemical compositions. The mineralization of fault and fracture sets were consistent with hydrothermal alteration and suggest an epithermal mineralization pattern in the area. These structural and mineralogical observations are consistent with a gossan style deposit though more analysis and investigation are needed to confirm this. The field results and lab results show promise of potential economically viable mineralization and warrants further investigation into the feasibility of large-scale mineral extraction.