Stable Isotope Constraints on Source, Contamination, and Alteration of Great Basin Igneous Rocks, and Implications for Metallogeny

Board Of Regents, Nshe, Obo University Of Nevada, Reno, Reno NV

Investigators

Abstract

EAR-0309935 Arehart Carlin-type deposits are amongst the richest and most important hydrothermal gold deposits in North America and appear to be associated in time and space with Eocene magmatism. In contrast, older magmatic episodes do not appear to have generated similar deposits. To better understand the interaction of ascending magmas, which were the driving force for these hydrothermal systems, with crustal rocks through which the magmas passed, measurements of stable isotopes of sulfur and oxygen will be made of unaltered plutonic rocks in the Great Basin. These measurements will be compared to similar isotopic measurements of crustal (cratonic basement, late Proterozoic rift-filling sedimentary rocks, Phanerozoic sedimentary rocks) and mantle materials that could have provided components to these igneous rocks. These data, when combined with extant geological, geochemical and geophysical data, will then be used to elucidate the crustal architecture of the region, to understand its control on the development of giant hydrothermal systems. These data will also address the question of why magmatism of different ages but in the same region, apparently did not generate the same large-scale metal redistribution in the crust that occurred in the Eocene. The proposed research will provide opportunities to students focused on developing careers in mineral deposits research . The combination of applied science supported by both industry and government will provide students exposure to multiple aspects of mineral deposit research, and is critical in training the upcoming generation of mineral geoscientists for positions in industry, academia, or government. Support for this research will help to maintain and enhance the infrastructure for research and education, including the Nevada Stable Isotope Laboratory