Rapid Emplacement of the Lower Deccan Traps and its Implications for Late Cretaceous Environmental Change

The Deccan Volcanic Province (DVP) represents one of Earth’s most voluminous continental flood basalt events, erupting an estimated 1.3 × 10⁶ km³ between ~66.3 and 65.5 Ma (Jay and Widdowson, 2008; Schoene et al., 2019). This study focuses on the Thakurvadi Formation (erupted ~66.3–66.1 Ma), and the overlying giant plagioclase basalt units, to understand magma evolution, crustal assimilation, and volatile element behaviour during eruption. Field mapping and trace element geochemistry of the Thakurvadi formation reveal systematic Cu/Ag variability that correlates with proxies for mantle heterogeneity. To test whether this variability reflects primary mantle signatures or is attributable crustal processes (assimilation, fractionation, degassing), we will integrate whole rock radiogenic isotope analyses (Sr, Nd, Pb, W). Preliminary Cu/Ag trends for my samples suggest links with radiogenic isotope signatures observed by Pakulla et al., (2023), potentially indicating ancient mantle source characteristics. By combining new isotopic data for my samples with the existing trace element and isotope datasets by Pakulla et al. (2023), we will be able to establish parental melt compositions, understand the extent of crustal contamination, and assess toxic element release (e.g., As, Se) during magma ascent and weathering. The resulting comprehensive geochemical framework will advance our understanding of DVP eruption dynamics, inform models of Large Igneous Province formation, and, by understanding the role of toxic elements, potentially contribute to understanding the environmental impacts of early Deccan volcanism on the Late Cretaceous environment.