2025/03/14 by Paul Botté, Alexis Licht, Lény Montheil +10 · 1 voice
Earth and Planetary Sciences · #Marine and environmental studies #Geology and Paleoclimatology Research
paper · doi:10.5194/egusphere-egu25-6438
openalex publication_date 2025/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
The Eocene-Oligocene Transition (EOT; ~34 Ma) is one of the most significant climate shifts of the Cenozoic era, representing the transition from the last warmhouse state to a coolhouse state. The EOT had a significant impact on terrestrial ecosystems and was synchronous with the "Grande Coupure", a major episode of faunal turnover in western Europe associated with the influx of multiple clades of Asian tetrapods. The impact of the EOT displays considerable regional variability in sedimentary records, and its role in the opening of dispersal corridors for the Grande Coupure remains unclear.In this study, we use sedimentology, magnetostratigraphy, biostratigraphy, and U-Pb geochronology to date a section comprising the EOT in the Çiçekdağı Basin, in central Anatolia, a region that sits on Balkanatolia, a biogeographic province proposed as a secondary dispersal pathway for the Grande Coupure that remains largely understudied. We then analyze stable and clumped isotopes from pedogenic carbonates to investigate the local paleoenvironmental evolution through the EOT.Our record captures a fluvio-lacustrine system spanning the Priabonian and the lower Rupelian, including the Oi-1 glaciation (~33.65Ma). Our sedimentological analyses reveal significant paleoenvironmental changes, including a major sedimentary unconformity in the latest Priabonian interpreted as a lake retreat related to a regional increase in aridity. This event also marks the onset of a long-term aridity trend in our stable isotope data. Furthermore, the stable and clumped isotopes analysis provide preliminary surface temperature estimates (Δ₄₇)discuss the implications of these paleoclimatic findings for understanding the environmental drivers behind faunal dispersals of the Grande Coupure. Keywords: Paleogene, EOT, Pedogenic carbonates, Anatolia, Clumped isotopes, Stable isotopes, Dispersals.