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

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 degrees C, consistent with other Maastrichtian temperature estimates, and an average seawater delta O-18 value of 0.2 +/- 0.8 parts per thousand VSMOW for the region during the latest Cretaceous (67.1-66.0 Ma). A notable temperature increase at similar to 66.4 Ma 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 delta O-18 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.

Automated summary

This study presents a new paleotemperature record of the Maastrichtian region based on clumped isotope data from fossil bivalves. The results show a mean temperature of 20.4°C, consistent with other estimates, and a notable temperature increase at around 66.4 Ma, likely related to the globally defined Late Maastrichtian Warming Event. Fluctuating seawater δO-18 values suggest alternating influences of warm southern-sourced waters and cool northern-sourced waters.