Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia)

A marked increase in oxygen isotope values (δ18Ow) between 2.97 and approximately 1.14 million years ago in the Shungura Formation suggests a shift from wetter to more arid conditions, likely due to changes in monsoon patterns and reduced rainfall over the Ethiopian Highlands. Unlike terrestrial proxies, stable oxygen isotopes (δ18Op) from crocodilian tooth enamel indicate stability in freshwater environments between 2.97 and 2.57 million years ago, followed by a restriction in aquatic diversity after approximately 2.32 million years, reflecting more arid conditions in the Turkana Depression. This study pioneers the use of crocodilian teeth as a paleoenvironmental archive, leveraging their resistance to diagenesis and sensitivity to water body isotopic composition, offering new insights into Plio-Pleistocene climate evolution.

Gardin, A., Pucéat, E., Garcia, G., Boisserie, J.-R., Euriat, A., Joachimski, M. M., Nutz, A., Schuster, M., & Otero, O. (2024). Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia). Biogeosciences, 21(2), 437–454. https://doi.org/10.5194/bg-21-437-2024