Pogge von Strandmann Philip A E, Jones Morgan T, West A Joshua, Murphy Melissa J, Stokke Ella W, Tarbuck Gary, Wilson David J, Pearce Christopher R, Schmidt Daniela N
Institute of Geosciences, Johannes Gutenberg University, 55122 Mainz, Germany.
London Geochemistry and Isotope Centre (LOGIC), Institute of Earth and Planetary Sciences, University College London and Birkbeck, University of London, Gower Place, London WC1E 6BS, UK.
Sci Adv. 2021 Oct 15;7(42):eabh4224. doi: 10.1126/sciadv.abh4224.
The Paleocene-Eocene Thermal Maximum (PETM; ~55.9 Ma) was a geologically rapid warming period associated with carbon release, which caused a marked increase in the hydrological cycle. Here, we use lithium (Li) isotopes to assess the global change in weathering regime, a critical carbon drawdown mechanism, across the PETM. We find a negative Li isotope excursion of ~3‰ in both global seawater (marine carbonates) and in local weathering inputs (detrital shales). This is consistent with a very large delivery of clays to the oceans or a shift in the weathering regime toward higher physical erosion rates and sediment fluxes. Our seawater records are best explained by increases in global erosion rates of ~2× to 3× over 100 ka, combined with model-derived weathering increases of 50 to 60% compared to prewarming values. Such increases in weathering and erosion would have supported enhanced carbon burial, as both carbonate and organic carbon, thereby stabilizing climate.
古新世-始新世极热事件（PETM；约5590万年前）是一个与碳释放相关的地质快速变暖时期，这导致了水文循环的显著增加。在此，我们使用锂（Li）同位素来评估整个PETM期间作为关键碳汇机制的全球风化作用的变化。我们发现全球海水（海洋碳酸盐）和局部风化输入（碎屑页岩）中的锂同位素均出现了约3‰的负偏移。这与大量粘土输入海洋或风化作用向更高物理侵蚀率和沉积物通量的转变相一致。我们的海水记录最好的解释是，在10万年的时间里全球侵蚀率增加了约2至3倍，同时与变暖前的值相比，模型推导的风化作用增加了50%至60%。风化和侵蚀的这种增加将支持碳酸盐和有机碳的碳埋藏增强，从而稳定气候。
