SOURCES OF EARLY DECCAN TRAPS MAGMAS AND IMPLICATIONS FOR VOLATILE EVOLUTION

Enormous volumes of melt are generated during the rapid emplacement of Large Igneous Provinces (LIPs), but the mantle sources of this melt and how these evolve through the course of magmatism remain uncertain. Lava compositions often reflect a melting history that includes a range of melting depths and mantle compositions. Here, we focus on trace element and melt inclusion data from the Deccan Traps LIP in India, which was emplaced between 67-65 Ma with the bulk of the eruption occurring in less than ~1Ma. The erupted products range from alkalic to tholeiitic. Temporal variations in magma flux have also been hypothesized. We combine olivine compositions with trace element and volatile data from a suite of melt inclusions from Deccan lavas to assess the relationship between variations in mantle sources (e.g. recycled pyroxenitic components from the deep mantle, melting of the subcontinental mantle lithosphere, and peridotitic mantle). Additionally, we examine changes in volatile contents and melting depths inferred from trace elements of Deccan lavas, and discuss the implications for the global carbon cycle around the Cretaceous-Paleogene boundary.