Oxygen Isotope ratios of Mesozoic Oceans Revisited
Our aim is to use the shallow marine record to caracterize coastal environmental changes occuring accross the two main climatic transition of the last 40 Myrs, the Eocene-Oligocene and the Middle Miocene, and to anchor these results to global signal using the Earth System model IPSL-CM5A2
Collaborators:- Guillaume Suan (main PI), Christophe Lecuyer, Romain Amiot, Jérémy Martin (LGLTPE - U. Lyon)
- Peggy Vincent, Sylvain Charbonnier (UPMC Sorbonne Universités, MNHN)
- Mathieu Daeron (CEA - LSCE)
- Nicolas Seon, PhD, October2019-XX (Sorbonne Universités, MNHN)
- Thomas Letulle, PhD, October2019-XX (UCBL - LGLTPE)
- Nina Papadomanolaki, Postdoc, July2021-June2023 (AMU, CEREGE)
Abstract
The main objective of the OXYMORE project is to provide the first reliable reconstructions of Mesozoic δ18OSW to verify or falsify the following hypotheses: H1) Mesozoic δ18OSW were very “low”, implying that the climate was cool and that other factors than CO2 control Earth’s climate on geological timescales; H2) δ18OSW values were “high” and Mesozoic climates truly represent a challenging but critical constraints for climate models; H3) large-scale glacial events impacted Mesozoic global δ18OSW values and temperatures. In order to reach these objectives, we have developed the following work plan involving three main work packages (WP), each subdivided into a number of specific associated tasks: WP 1) characterization of Mesozoic δ18OSW values through brachiopod shell geochemistry; WP 2) characterization of Mesozoic δ18OSW values through marine tetrapod geochemistry; WP 3) numerical simulations of modern and Mesozoic δ18OSW values. Our project will be the first attempt to comprehensively reconstruct Mesozoic δ18OSW through time and space using complementary and innovative approaches based on modern and ancient data and numerical climate models. Given the central importance of δ18OSW estimates for reconstructing past climates, the expected results of the project will set the stage for improving potentially all future studies of Mesozoic climates. These findings will also allow testing the ability of climate models to simulate climate conditions under high CO2 levels, with implications for future climate evolution and environmental policies.