Clumped-isotope-derived climate trends leading up to the end-Cretaceous mass extinction in northwestern Europe

Abstract

Paleotemperature reconstructions of the end-Cretaceous interval document local and global climate trends, some driven by greenhouse gas emissions from Deccan Traps volcanism and associated feedbacks. Here, we present a new clumped-isotope-based paleotemperature record derived from fossil bivalves from the Maastrichtian type region in southeastern Netherlands and northeastern Belgium. Clumped isotope data document a mean temperature of 20.4±3.8°C, consistent with other Maastrichtian temperature estimates, and an average seawater δ18O value of 0.2±0.8‰ VSMOW for the region during the latest Cretaceous (67.1-66.0Ma). A notable temperature increase at ∼66.4Ma is interpreted to be a regional manifestation of the globally defined Late Maastrichtian Warming Event, linking Deccan Traps volcanic CO2 emissions to climate change in the Maastricht region. Fluctuating seawater δ18O values coinciding with temperature changes suggest alternating influences of warm, salty southern-sourced waters and cooler, fresher northern-sourced waters from the Arctic Ocean. This new paleotemperature record contributes to the understanding of regional and global climate response to large-scale volcanism and ocean circulation changes leading up to a catastrophic mass extinction.