Rapid emplacement of the lower Deccan Traps and its implications for Late Cretaceous environmental change

The Deccan Volcanic Province (DVP), erupted around 66.3 to 65.5 million years ago, is one of the largest and best-preserved Continental Flood Basalt Provinces (CFBP). The most active phase of the DVP is estimated to have lasted for about 1 million years when most of the total volume (1.3 x 10⁶ km³) was erupted. The eruption of the DVP coincides with the Cretaceous‐Paleogene (K–Pg) mass extinction and is thought to have significantly impacted the environment, thus, contributing to the extinction event. This research focuses on the Thakurvadi Formation of the DVP, which is older than the K–Pg boundary and erupted from ~66.3 to 66.1 Ma. We aim to explore links between the Thakurvadi Formation and environmental perturbations during the Late Cretaceous, by combining detailed field observations with geochemical data. During the transit of magma through the continental crust, the magma can become enriched in toxic elements, such as arsenic and lead, especially during assimilation of pre–existing continental crust. The premise of this study is to assess the effects of crust assimilation, fractionation and degassing on the behaviour of toxic elements using new geochemical analyses of the Thakurvadi Formation and two giant plagioclase basalt units that bracket it. With this approach, and combined with detailed fieldwork of these units, we aim to better understand the delivery of toxic elements to the environment during the eruption, cooling, and alteration (e.g., weathering) of the lava flows. Overall, the findings of this study will enhance our understanding of the lower DVP eruption dynamics and their broader implications for global environmental change and mass extinction. Previous research has highlighted the significant environmental changes that coincide temporally with the DVP eruptions, including global temperature changes and ocean acidification, which may have contributed to the K–Pg mass extinction. Here, we investigate in detail the links between toxic elements derived from Deccan volcanism and pre‐K–Pg extinction environmental change.