Millennial-scale changes in marine lithofacies during the Paleocene-Eocene Thermal Maximum: A deep-time analog for Anthropocene hydrologic and acidification impacts

Extreme climatic events can significantly alter marine lithofacies. However, global oceanic sediment patterns during deep-time hyperthermal events, which are potential analogues for the hydrologic and climatic impacts of modern anthropogenic warming, remain poorly constrained. Here, we compile 162 marine stratigraphic records to track millennial-scale sediment dynamics during the Paleocene–Eocene Thermal Maximum (PETM). We find that sedimentation was primarily controlled by hydrologic intensification (resulting in ∼36% carbonate platform demise), eustatic fluctuations (resulting in ∼52% siliciclastic shelf retrogradation), and ocean acidification (resulting in ∼41% deep-sea calcareous sediment replacement). Lithofacies changes along continental margins show distinct latitudinal zonation, reflecting variations in hydrologic intensity and carbonate productivity. The impact of eustatic sea-level change is strongest in region where hydrologic effects are muted. Deep-sea acidification was widespread, with the strongest expression in the Atlantic, and weaker effects in the Pacific and Indian oceans. Widespread carbonate “overshoot” following PETM recovery suggests enhanced continental weathering. This study implies that ongoing anthropogenic warming could rapidly reorganize marine sedimentation through intensified hydrological cycle, accelerated sea-level rise, and ocean acidification on centennial timescales, much faster than during the PETM and potentially with greater magnitude.