Terrestrial ecosystem and climate dynamics during the Paleocene–Eocene Thermal Maximum (~56 Ma) in the high southern latitudes: An integrated palynological/ organic geochemical study of the Margaret Point section, Southern Australia

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Due to anthropogenic emissions, atmospheric CO2 concentrations may reach 1800 ppmv around the year 2300 should emissions continue unabated. The last time in Earth’s history when such extreme CO2 concentrations prevailed was the late Paleocene to early Eocene (c. 60-50 Ma ago), and particularly during the several transient hyperthermals that punctuated this greenhouse interval. The rapid warming and high carbon input during these hyperthermals bear analogies to today’s anthropogenic carbon release and its climatic consequences. Among these hyperthermals, the Paleocene-Eocene Thermal Maximum (PETM; c. 56 Ma) has reached particular attention. Characterized by a massive injection of isotopically light carbon into the ocean-atmosphere system, it represents an excellent paleoanalog for present climate change as a result of excess carbon emissions.Information on the consequences of the PETM for terrestrial ecosystems is yet mainly from the mid-latitudes of the Northern Hemisphere. For the Southern Hemisphere, it is restricted to pollen data from New Zealand and Ocean Drilling Program Site 1172 off Tasmania. Because these data are not only of limited temporal resolution, but also not fully representative of PETM-induced vegetation change in the high-latitude Southern Hemisphere, there is a need for additional, temporally highly resolved proxy data from these latitudes. This project therefore aims to reconstruct PETM-induced terrestrial ecosystem dynamics in southern Australia via the analysis of sporomorphs from an outcrop at Point Margaret, Victoria (paleolatitude: c. 60 deg S). Because funding for a PhD position has already been granted otherwise, here only funds for student helpers, consumables and travel are asked for. Extensive pilote work has shown that the Point Margaret section contains the onset of the PETM and extends into the body of the carbon-isotope excursion (CIE). The sporomorph data will allow to establish a detailed, temporally highly resolved vegetation record for the latest Paleocene well into the PETM CIE. Quantitative sporomorph-based climate estimates will allow to determine the magnitude of local PETM warming. Comparison of the palynological data with organic geochemical (MBT-CBT) temperature data that will be provided by collaboration partners, and the CIE will allow to identify the phase relationships between carbon-cycle perturbation, vegetation change and temperature change. The data to be generated for the Point Margaret section will not only yield yield unprecedented insight into the response of terrestrial ecosystems in the high outhern latitudes to PETM-induced climate change; they will also help to advance the general understanding of the long-term reaction of terrestrial ecosystems to major increases in greenhouse-gas concentrations and temperature.