GEO-CM: The enrichment of critical metals in porphyry Cu deposits: a high-resolution mineral-scale approach to assess temporal and spatial variation in ore forming processes

University Of Nevada Las Vegas, Las Vegas NV

Investigators

Abstract

We live in a mining-based society and critical and other metals are a key component in military defense applications and the transition to a low carbon economy. Most critical metals are produced as co- or by-products of major metals, for example the critical metal tellurium is produced from copper mining. This research will assess the processes that concentrate critical metals in a class of ore deposits called porphyry copper deposits, a common and economically important type of mineral deposit in the SW U.S. The conditions needed to enrich critical metals, how these processes vary spatially and if they changed over time is currently not known. Results that will be generated by graduate and undergraduate researchers will allow the team to accurately assess the resource potential of porphyry copper deposits as a domestic source of critical metals for the U.S. ensuring a secure supply of these metals for the future. This work will also provide place-based learning opportunities for students and produce a 3D virtual field trip of the Yerington district for students who are unable to participate in fieldwork, and facilitate remote access to a world-class geological district. This study utilizes pyrite as a recorder of ore-forming processes and assesses its role as a repository of critical metals within mineralizing systems. Pyrite growth tracks changes in metal sources and chemical and physical changes in fluid compositions that are preserved as micron-scale chemical and isotopic variations across individual mineral grains. The ubiquitous nature of pyrite within porphyry copper deposits combined with the wide range of metals that can be incorporated into pyrite make it the ideal candidate for in situ mineral-scale analysis. This study, focusing on the Yerington District, Nevada, that represents a complete cross-section of a porphyry copper deposit, will employ a systematic approach to mineral-scale analysis by combining trace metal mapping with quantitative geochemical and isotopic analytical transects. These data will allow the team to redefine ore formation models in high-definition, that have historically been developed using whole-rock geochemical data, allowing them to accurately link changing processes to the enrichment of critical metals. This project is jointly funded by NSF GEO EAR, Petrology and Geochemistry and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.