Low Chemical Weathering Intensity, Enhanced Erosion, and Euxinic Conditions Along the Norwegian Margin During the Paleocene‐Eocene Thermal Maximum

Abstract The Paleocene–Eocene Thermal Maximum (PETM; ∼55.9 Ma) was a rapid global warming event marked by intensified hydrological cycling, enhanced continental weathering, and widespread ocean deoxygenation. Although the extent of anoxic basins during the PETM is relatively well documented, the contribution of high‐latitude continental weathering to regional ocean redox dynamics remains unclear, leaving the spatial impact of weathering on ocean biogeochemistry poorly constrained. Here, we use elemental geochemical data from sediments recovered from the Vøring Basin, North Atlantic during International Ocean Discovery Program (IODP) Expedition 396, to reconstruct variations in continental weathering intensity and redox conditions across the PETM. Our results show that high accumulation rates during the PETM coincided with low chemical weathering relative to underlying pre‐PETM strata, indicating that rapid burial limited chemical alteration, although accumulation rates in the pre‐PETM interval are not well constrained. This pattern likely reflects intensified rainfall, which primarily enhanced physical erosion and delivered large amounts of detrital material to the basin while limiting chemical weathering. The influx of fresh, reactive detrital material from the North Atlantic Igneous Province (NAIP) increased the supply of bioavailable nutrients, likely stimulating elevated primary productivity and contributing to the development of euxinic bottom waters during the onset of the PETM. On the boreal mid‐Norwegian margin, our data suggest that enhanced physical erosion, rather than chemical weathering, dominated continental responses to extreme greenhouse forcing, promoting nutrient enrichment, transient euxinia, and organic carbon burial.