The Eocene-Oligocene climate transition in the Alpine foreland basin: Paleoenvironmental change recorded in submarine fans

Abstract

The Eocene-Oligocene transition (EOT) was a period of considerable environmental change, signifying the transition from Paleocene greenhouse to Oligocene icehouse conditions. Preservation of the sedimentary signal of such an environmental change is most likely in net-depositional environments, such as submarine fans, which are the terminal parts of sedimentary systems. Here, using sedimentary and stable isotope data from the Alpine foreland basin, we assess whether this major climatic transition influenced the stratigraphic evolution of submarine fans. Results indicate that fine-grained deposition in deep-water environments corresponds to positive δ13C excursions and eustatic highstands, while coarse-grained deposition corresponds to negative δ13C excursions and eustatic lowstands during the earliest Oligocene. While alternative explanations cannot be ruled out on the basis of this dataset alone, our results suggest that eustatic fluctuations across the EOT and into the early Oligocene influenced sediment supply to deep-water environments.