Eocene to Oligocene vegetation and climate in the Tasmanian Gateway region were controlled by changes in ocean currents and <i>p</i>CO<sub>2</sub>

Abstract. Considered one of the most significant climate reorganizations Cenozoic period, Eocene–Oligocene Transition (EOT; ca. 34.44–33.65) is characterized by global cooling and first major glacial advance on Antarctica. In southern high latitudes, EOT primarily recorded in marine realm, its extent effect terrestrial vegetation are poorly documented. Here, we present new, well-dated, continuous, high-resolution palynological (sporomorph) data quantitative sporomorph-based estimates recovered from East Tasman Plateau (ODP Site 1172) to reconstruct dynamics late Eocene (37.97 Ma) early Oligocene (33.06 Ma). Our results indicate three transitions four communities occupying Tasmania under different precipitation temperature regimes: (i) a warm-temperate Nothofagus–Podocarpaceae-dominated rainforest with paratropical elements 37.97 37.52 Ma; (ii) cool-temperate Nothofagus-dominated secondary Podocarpaceae rapidly expanding taking over regions previously occupied warmer taxa between 37.306 35.60 (iii) fluctuation warm-temperate–paratropical cool temperate forest 35.50 34.49 Ma, followed phase across (34.30–33.82 Ma); (iv) post-EOT (earliest Oligocene) recovery association 33.55 33.06 Ma. Coincident changes stratification water masses sequestration carbon surface Southern Ocean, our Ma (phase ii) showed 2–3 ?C cooling. The unusual warm cold 34.59 suggested be linked initial deepening Tasmanian Gateway, allowing eastern come influence associated proto-Leeuwin Current (PLC). Further above, show mean annual declining about 2 before recovering earliest Oligocene. This phenomenon synchronous regional during pCO2. However, rebound along transient atmospheric pCO2 sustained promoting PLC throughflow. main transitional events studied interval (late Eocene–earliest Gateway region suggest that ocean circulation due accelerated may not have been solely responsible for dynamics; series events, including change masses, waters, pCO2, also played vital roles.