CAREER: Tracking mantle carbon through the life cycle of Large Igneous Provinces

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Throughout Earth’s history, enormous volcanic eruptions known as Large Igneous Provinces (LIPs) coincide with mass extinction and climate warming events. Tracking CO2 release from these eruptions is key to resolving links between magmatism and observed climatic changes. However, because CO2 tends to leak out of magmas, measuring CO2 from past eruptions is challenging. This CAREER award will investigate distinct LIP sources using carefully selected samples from three LIPs that may record past CO2 concentrations. The goal of this work is to clarify how, when, and why some LIP eruptions cause major disruptions in climate and life on Earth but others do not. New approaches will track CO2 deeper in the Earth, inform estimates of past climate, and help to project future climate change. The project uses peer mentoring in undergraduate course to integrate research, public engagement and teaching. The work also supports graduate and undergraduate student training at a public institution with a diverse student population. Part of the project includes collaboration with a film-maker to convey lessons from past climate disruptions through a new documentary and outreach at the New York Virtual Volcano Observatory. The film and outreach will make the experience of exploring a volcano accessible to thousands of visitors each summer. The two primary scientific objectives of this work are to find the most faithful records of magmatic CO2 in LIP magmas, and to control for different mantle sources to understand mantle carbon release through the life cycle of LIPs. Accordingly, this project frames a series of natural experiments that contrast: 1) different types of melt inclusion volatile and trace element records, and 2) samples from oceanic and continental LIPs that tap distinct and evolving mantle sources. These natural experiments will reveal the strengths and weaknesses of various petrologic archives of CO2 in basaltic magmas, including a range of melt inclusion host crystals and geochemical proxies for original CO2. The results will be used to test the hypothesis that it is the evolving mantle reservoirs tapped during LIP melting—rather than sedimentary country rocks as is commonly assumed—that determine the severity and pace of climatic warming and carbon cycle disruption in response to magmatism. If successful, this project will elucidate the volatile systematics of poorly understood reservoirs in the mantle including the continental mantle lithosphere, recycled material in plumes, and high 3He/4He primordial mantle—in the process demonstrating how the origins of LIPs in the mantle can set the blueprint for surface CO2 release and climate change.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.