A large and mostly volcanic carbon source drove the Paleocene-Eocene Thermal Maximum (NERC grant NE/H017356/1)

Global warming during the Palaeocene-Eocene Thermal Maximum (PETM, ~56 Ma) is commonly interpreted as being driven by massive destabilization of carbon from surficial sedimentary reservoirs. If correct, this has important implications for the amplification of future fossil fuel emissions via carbon-climate feedbacks. In our study we provided new paired records of boron and carbon isotope changes in the ocean that questions this long-held interpretation. Our data are implemented in an Earth system model to reconstruct the unfolding carbon cycle dynamics across the event. Strong evidence for a larger (>10,000 PgC) and on average isotopically heavier (> -17‰) carbon source leads us to identify volcanism associated with the North Atlantic Igneous Province as the main driver of the PETM. We also find that although organic carbon feedbacks with climate played a more minor role in driving the event than previously thought, organic matter burial was important in ultimately sequestering this carbon and driving the recovery of the system. Data presented in this data set comprise geochemical elemental, as well as boron, carbon and oxygen isotopic data from surface dwelling foraminifera Morozovella Subbotina. Alongside the boron isotopic data we also provide reconstructed surface water pH with corresponding uncertainties for our preferred pH reconstruction.古新世-始新世极热事件（Palaeocene-Eocene Thermal Maximum, PETM, 约56 Ma）期间的全球变暖，通常被认为由地表沉积储层中的碳大规模失稳所驱动。若该解释成立，将对未来化石燃料排放通过碳-气候反馈产生的放大效应具有重要启示意义。本研究提供了海洋硼与碳同位素变化的成对同步记录，对这一长期占据主流的解释提出了质疑。我们将所得数据整合至地球系统模型，以重建该事件全过程中的碳循环动态演化。有力证据表明，此次碳源规模超过10000 PgC（拍克碳，petagram of carbon），且平均同位素组成更重（δ¹³C＞-17‰），据此我们认定与北大西洋火成岩省（North Atlantic Igneous Province）相关的火山活动是PETM的主要驱动因素。我们还发现，尽管气候与有机碳之间的反馈在推动此次事件中的作用较此前认知更为有限，但有机质埋藏在最终固存该部分碳并推动系统恢复方面发挥了关键作用。本数据集包含地球化学元素数据，以及栖息于表层水体的有孔虫（foraminifera）Morozovella Subbotina的硼、碳、氧同位素数据。除硼同位素数据外，我们还提供了优选的表层海水pH重建结果及其对应的不确定度。