U-PB ZIRCON GEOCHRONOLOGY OF THE SOUTHERN MALWA PLATEAU BASALT: DECCAN TRAPS, INDIA (Invited Presentation)

The temporal relationship between emplacement of large igneous provinces (LIPs) and mass extinctions is well known. However, the potential causal relationship between paleo-environmental change and volcanic eruptions remains debated. The most commonly proposed driver of paleo-environmental degradation is the syn-eruptive release of volatiles. Precise chronologies of eruption coupled with robust estimates for eruptive volumes are needed to assess the efficacy of this process. Recent geochronologic results from the Western Ghats region of the Deccan Traps LIP in India have defined four periods of high-eruptive flux during the latest Cretaceous and earliest Paleogene. However, the volume of basalt that was erupted within each pulse remains poorly constrained due, in part, to uncertainties in the correlation between the volcanic stratigraphy of the Western Ghats and basalts on the periphery of the province. Here we present new U-Pb zircon geochronology from the Malwa Plateau on the northern margin of the Deccan Traps LIP. This region includes 42,000 km³ of basalt, or ~7% of the inferred total volume of the LIP. Our dates provide a means to correlate the Malwa Plateau basalt to the volcanic stratigraphy of the Western Ghats and we use this information to revise our model of eruption rates during emplacement of the province. They also tightly constrain the C30N/C29R magnetic reversal, thereby improving correlation between our temporally constrained eruption rates and paleoenvironmental records from sedimentary sections around the globe. These revised records are combined to speculate on potential links between eruption of the Deccan Traps LIP and latest Cretaceous environmental instability.