Collaborative Research: The Mantle Sources of Large Igneous Provinces

Large igneous provinces are formed when very large volumes of magma quickly erupt on the Earth’s surface, covering millions of square kilometers. These huge volcanic events host some of the world’s largest critical mineral ore deposits. Two of the largest such eruptions are the Siberian Traps and the Deccan (India) igneous provinces. Eruptions in the two provinces are similar in volume and had similar eruption rates. The compositions of the two regions are distinct. In the Siberian traps, there are world-class mineral deposits, rich in nickel, cobalt, and platinum group elements. The critical mineral deposits are absent in the Deccan. This project will analyze samples from each province to understand how their sources formed and what processes drive the differences between them. This research will improve geoscientists’ understanding of other large igneous provinces. This work will train the next generation of geoscientists, including high school and undergraduate students, and a postdoctoral fellow. The Siberian Traps Large Igneous Province (LIP) and the Deccan Volcanic Province are the two largest Phanerozoic volcanic eruptions. Despite similarities in the scales and tempo of eruption, key geochemical tracers reveal that Siberian Traps lavas have a “volcanic arc flavor” enriched in fluid-mobile elements while Deccan lavas tap a more “dry” source, similar to modern ocean-island basalts. The Siberian Traps LIP hosts world-class copper - nickel -platinum group element magmatic sulfide mineralization (Norilsk 1 intrusion). Similar mineralization is absent in the Deccan Volcanic Province. This research aims to constrain the competing roles of deep mantle sources (e.g., plume and subcontinental lithosphere contributions) vs. shallow processes (e.g. crustal contamination) that drive the differences between these LIPs. Analyses include a novel combination of the fluid-mobile elements molybdenum, thallium, and boron and their stable isotope systematics. Additional data will include major, trace element, and radiogenic isotope data on well-characterized samples from precisely known stratigraphic locations obtained through deep boreholes. The goal is to identify and quantify recycled, fluid-rich (e.g., subducted sediments, carbonates, serpentinites) and other components in the mantle sources of LIPs, constrain the competing roles of source composition vs. surface-derived crustal contamination, and determine the link between volatile-rich components and chalcophile metal mobilization and mineralization. This project is important for characterizing critical mineral formation. The project will train undergraduate students and a postdoctoral fellow and includes a high school internship outreach program that will expose high school students to cutting edge geoscience research. 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.