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

• Main Author: O'Hora, Heidi
• Format: Article in Journal/Newspaper
• Language: English
• Published: My University 2021
• Subjects: Geological Sciences; Science; Arctic; Arctic Ocean; Climate change
• Online Access: https://dx.doi.org/10.7302/4001; http://deepblue.lib.umich.edu/handle/2027.42/171489

Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology or Earth and Environmental Sciences, Department of Earth and Environmental Sciences : Paleotemperature reconstructions linked to Deccan traps volcanic greenhouse gas emissions and associated feedbacks in the lead-up to the end-Cretaceous meteorite impact and extinction document local and global climate trends during a key interval of geologic history. Here, we present a new clumped-isotope-based paleotemperature record derived from fossil bivalves from the Maastrichtian type region, in southeast Netherlands and northeast Belgium. Clumped isotope data documents a mean temperature of 19.2 3.8 C, consistent with other Maastrichtian temperature estimates, and an average seawater δ18O value of -0.2 0.9‰ VSMOW for the region during the latest Cretaceous (67.1–66.0 Ma). A notable temperature increase at ~66.4 Ma is interpreted to be a regional manifestation of the globally-defined Late Maastrichtian Warming Event, linking Deccan Traps volcanic CO2 emissions prior to the end-Cretaceous extinction 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.