Michael Alexander, Utah Valley University
The Tintic Mining District is located in central Utah on the eastern edge of the Basin and Range Province. This area experienced significant hydrothermal alteration associated with volcanism in the early Cenozoic Era. This hydrothermal alteration was productive of sulfide ore deposition along fissure veins, including ores of copper, gold and silver. Previous aeromagnetic surveys showed that porphyry copper assemblages are associated with mappable anomalies in the Earth’s total magnetic field. The magnetic anomalies were interpreted as resulting from buried intrusive igneous rocks associated with the porphyry copper assemblages. The objective of this research is to map buried fissure veins on property owned by NorthStar Mine using a ground-based survey of anomalies in the Earth’s total magnetic field. This study will be the first geophysical mapping of fissure veins in this area. Previous work by the author and other Utah Valley University students showed that total magnetic field anomalies could be used to map halloysite clay deposits, the copper sulfide deposits associated with buried basaltic dikes, and a wide variety of igneous rock bodies including buried bodies of quartz monzonite, rhyolite and tuff. Because the igneous rocks are considered to be the source of hydrothermal fluids, further mapping of the distribution of igneous rocks could give some insight into the migration of fluids that deposited ore in fissure veins. The ground-based magnetic survey will be carried out using the Geometrics G-856 Proton Precession Magnetometer. Magnetic susceptibilities of outcrops will be measured using the handheld SM-10 Magnetic Susceptibility Meter. Rock samples will also be collected for crushing and more precise measurement of magnetic susceptibility in the lab using the Bartington MS3 Magnetic Susceptibility Meter. Mapped magnetic anomalies will be compared with possible subsurface rock bodies using the IX2D Magnetic Interpretation Software. All necessary equipment is currently owned by the Department of Earth Science. This research is being carried out in cooperation with NorthStar Mine. Results will be reported at the meeting.