Author name: Sean P. Gaynor

Reconstructing the tempo and emplacement mechanisms of large igneous provinces (LIPs) and establishing potential links to environmental change and biological crises requires detailed and targeted high-precision geochronology. Contact metamorphism during LIP intrusive magmatism can release large volumes of thermogenic gas, so determining the timing of these events relative to global climate change is crucial. The most reliable age information comes from U-Pb geochronology; however, LIP mafic igneous rocks do not commonly crystallize U-bearing minerals, such as zircon or baddeleyite. Recent work has shown that U-rich minerals can crystallize in fractionated melt pockets in intrusive components of LIPs after contamination of the melt by sedimentary rocks at emplacement level. Zircon and baddeleyite from these pockets make high-precision U-Pb geochronology of LIPs possible, but these unique mechanisms add other complexities.

Earth’s history has been punctuated by extraordinary magmatic events that produced large igneous provinces (LIPs). Many LIPs induced global changes, including millennial-scale warming, terrestrial and oceanic mass extinctions, oceanic anoxic events, and even glaciations. Research over the past 20 years has shown that shallow crustal degassing is an important factor contributing to the environmental impact of LIPs. Contact metamorphism in sedimentary basins can generate huge gas volumes, and operates as a function of magma volume and the architecture of LIP plumbing systems. Numerous open questions remain concerning the role of LIPs in triggering rapid and lasting changes, whose answers require collaboration across geoscientific disciplines. In this issue, we present the status of five key research themes and discuss potential ways forward to better understanding these large-scale phenomena.