CAREER: Did Carlin-type Gold Come From Magmas?

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Nearly 80% of the gold produced in the United States comes from northern Nevada's Carlin-type gold deposits. Despite more than 50 years of production and the great economic importance of these deposits, their genesis is debated. Some researchers argue that the gold must have come from magmas emplaced in the shallow crust, while others propose that the gold was already present in the sedimentary host rocks and magmatism was not necessary to create economic concentrations of gold. This project addresses the scientific controversy and aims to facilitate exploration efforts through improved understanding of how Carlin-type gold deposits formed. Particularly in Nevada's prolific Carlin trend, many studies have attempted to link the gold to Eocene magmas; although the data are permissive, unequivocal evidence remains elusive. This project takes a new approach by focusing on the northern Battle Mountain district, where there is Carlin-type gold, porphyry and skarn deposits that are known to have a magmatic origin, and distal disseminated deposits bearing hybrid characteristics of all of those deposit styles. In order to determine whether the distal disseminated deposits link the Carlin-type gold to causative magmatic intrusions, this project will characterize the nature of the ore fluids and the timing of mineralization at adjacent gold deposits. In addition to addressing a long-standing knowledge gap in economic geology, this work contributes towards advancing broader geoscience initiatives to characterize magmatism and metal flux in the crust. Despite the critical importance of mining to national security and the increasingly complex environmental and social framework in which mining occurs, the United States has a shortage of skilled labor in this sector. This project integrates teaching and research on ore deposits to develop innovative curricula that will recruit and retain students in educational pathways leading to careers in mining. The project science will be incorporated into a graduate field course and undergraduate case study modules at Colorado School of Mines, and a K-12 teacher training workshop conducted in collaboration with Relay Graduate School of Education and the Colorado Mining Association. In addition to serving as the basis for two PhD dissertations, the 5-year project will reach 50 graduate students, 150 undergraduate students, 25+ science teachers, and 600+ K-12 students.