Linking climatic changes and North Atlantic volcanism across the Paleocene-Eocene Thermal Maximum at Fur, Denmark

Abstract

This thesis focuses on Danish sediments deposited in the eastern North Sea basin between 56-54.6 million years ago, including an extreme global warming event called the Paleocene-Eocene Thermal Maximum (PETM) that was triggered by large emissions of carbon. We find evidence that sea surface temperatures increased ~10 °C across the PETM onset. This warming was accompanied by an intensified hydrological cycle, enhanced erosion, an increase in the production and burial of organic matter, and a decrease in bottom-water oxygen content. Hundreds of ash layers from the North Atlantic Igneous Province (NAIP) are preserved in the Danish sediments. These are the largest explosive basaltic eruptions known, yet their formation is poorly understood. We find that these ashes were formed due to violent magma-water interactions in a shallow-marine environment during the opening of the northeast Atlantic Ocean. Our sea surface temperature proxy shows cool periods corresponding to spells of abundant ash deposition from the NAIP. We propose that these explosive NAIP eruptions may have emitted enough sulfur to have a regional cooling effect particularly in the period immediately following the PETM.