Evolution of sedimentary basins took place in the Barmer, Jaisalmer, and Bikaner regions during K-T (Cretaceous–Tertiary) time in western Rajasthan, India. These intracratonic rift basins developed under an extensional tectonic regime from Early Jurassic to Tertiary time. Rift evolution resulted in alkaline magmatism at the rift margins. This magmatism is dated at 68.5 Ma and has been considered an early phase of Deccan volcanism. Deccan volcanism, sedimentary basin development, and the alkaline magmatism of western Rajasthan have thus been considered the products of Réunion plume activity. However, sedimentary basin evolution began in western Ra-jasthan prior to Deccan volcanism and K-T...