Late Paleocene CO<sub>2</sub> drawdown, climatic cooling and terrestrial denudation in the southwest Pacific

Abstract. ???????Late Paleocene deposition of an organic-rich sedimentary facies on the continental shelf and slope New Zealand eastern Australia has been linked to short-lived climatic cooling terrestrial denudation following sea level fall. Recent studies confirm that organic matter in this facies, termed “Waipawa organofacies”, is primarily origin, with a minor marine component. It also unusually enriched 13C. In study we address cause enrichment. For Waipawa organofacies its bounding Taylor White section, Hawke's Bay, paired palynofacies carbon isotope analysis heavy liquid-separated density fractions indicate heaviest ?13C values are associated degraded phytoclasts (woody plant matter) 13C enrichment may be partly due lignin degradation. Compound-specific stable analyses samples from mid-Waipara (Canterbury) sections display similar trends further reveal residual ? 2.5 ‰ higher biomarkers (long chain n-alkanes fatty acids) 2 ‰–5 change subordinate biomarkers. Using relationship between atmospheric CO2 C3 tissue values, determine 3 increase represent 35 % decrease CO2. Refined age control for indicates occurred 59.2 58.5 Ma, which coincides interval carbonate dissolution deep oxygen maximum (POIM, 59.7–58.1 Ma) onset (PCIM, 59.3–57.4 Ma). This association suggests during time cool conditions increased burial. supported by published TEX86-based surface temperatures pronounced regional deposition. We suggest reduced greenhouse gas emissions volcanism accelerated burial, tectonic factors, resulted global cooling, growth ephemeral ice sheets fall level. Accompanying erosion deep-sea sediment archives have hidden evidence “hypothermal” event until now.