CRETACEOUS-PALEOCENE-EOCENE SEA SURFACE TEMPERATURE EVOLUTION AT HIGHER LATITUDES: CONSTRAINTS FROM TEX86 AND PLANKTONIC FORAMINIFERAL OXYGEN ISOTOPES (Invited Presentation)

It is well established that greenhouse conditions prevailed during the Cretaceous-Paleocene-Eocene. The high latitudes represent areas of significant climatic importance due to polar amplification of global warming such that determining the exact nature of climatic warming remains an active topic of research. Paleo-proxies provide valuable observational constraints on greenhouse conditions at higher latitudes. Here we provide a compilation and synthesis of available planktonic foraminiferal δ¹⁸O (δ¹⁸O_pl) and TEX₈₆-SST proxy data for the Cretaceous-Paleocene-Eocene from higher, >±48°, paleolatitudes. Our reconstruction of the evolution of higher latitude SSTs reveals temporal changes. In the early Cretaceous, TEX₈₆ reconstructions indicate that SSTs were broadly stable, ~25 °C, at higher latitudes. In the early late Cretaceous, δ¹⁸O_pl-SSTs document higher latitude warming, with peak SSTs of ~30 °C during the Cretaceous thermal maximum (Cenomanian-Turonian). This extreme warmth was followed by a long-term climate deterioration, with δ¹⁸O_pl-SSTs recording ~15 °C of cooling at higher latitudes, from the Turonian to end Maastrichtian. For the Paleocene, temperature proxy records are temporally sparse but suggest a temperate climate at high southern latitudes, which culminated with extreme warmth at the Paleocene-Eocene Thermal Maximum. In the early Eocene the TEX₈₆ proxy indicates higher latitude SSTs were in excess of 30° C at >±55°. The higher latitudes then underwent substantial cooling, ~6 °C based on TEX₈₆-SSTs, during the descent towards the icehouse. These long-term temperature trends are broadly consistent with benthic oxygen isotope records. Our higher latitude SST compilation provides an up-to-date target for modelling studies investigating the mechanics of greenhouse climates.