Project Details
Projekt
Investigating the role volcanism played in the onset and termination of the Paleocene-Eocene Thermal Maximum, using sediments from IODP Expedition 396
Applicant
Professorin Dr. Katharina Pahnke-May, since 3/2023
Subject Area
Geology
Oceanography
Oceanography
Term
since 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 507196996
Volcanic eruptions are known to impact the climate in several ways. These range from short-term (decadal) impacts such as sulfate injection reducing incoming solar radiation, leading to cooling, to medium-term (millennial) impacts such as warming from carbon dioxide degassing. Finally, long-term (million-year) impacts such as enhanced weathering of emplaced basalts may lead to carbon dioxide removal and cooling. Million-year long periods of intense volcanism known as Large Igneous Provinces (LIPs) may have particularly profound impacts on climate, with several LIPs linked to mass extinctions because of climatic change. The Paleocene-Eocene Thermal Maximum (PETM), a 200,000 year long period of intense global warming c.56 million years ago, occurred at the same time as the emplacement of a LIP, the North Atlantic Igneous Province (NAIP). NAIP emplacement has been suggested as a cause of the PETM, due to the release of carbon dioxide and methane during the volcanism enhancing the greenhouse effect and leading to rapid warming. It has also been suggested volcanic ash deposition during the NAIP may have acted to cool the climate, enhancing the carbonate sink in marine sediment. As such, the PETM is an ideal case study for investigating the holistic (in both warming and cooling) role of volcanism on the Earth system. International Ocean Discovery Program (IODP) Expedition 396, of which I was a participant, successfully recovered a series of unprecedentedly long PETM-age sedimentary sequences from the Norwegian margin. In this project I intend to carry out detailed descriptive, geochemical, and modelling-based investigations using the sediments from Expedition 396 to fully document the role NAIP volcanism played in the PETM. Firstly, assessment of the intensity of volcanism will be used to construct new estimates of carbon dioxide, methane, and sulfate emission to determine the role of degassing in climate forcing. Detailed geochemical investigations will assess the impact of volcanic ash deposition on carbon cycling, focussing on the role of ash as a nutrient supplier to phytoplankton. The potential impact of ash deposition on the marine sedimentary carbonate sink will also be investigated, using geochemical and isotopic tools. Finally, these findings will be combined using sophisticated Earth system models to diagnose the exact role volcanism on global climate change through the PETM. The expected results will have far reaching implications for our understanding of the role of LIP emplacement and volcanic ash deposition in climatic change. Sediments from Expedition 396 provide a unique opportunity to investigate the geochemical imprint of volcanism at a resolution previously unobtainable. The PETM is one of the best studied, yet most enigmatic climatic perturbations in Earth history, and so the findings of this proposed work will lead to significant improvement of our understanding of the period.
DFG Programme
Infrastructure Priority Programmes
International Connection
Norway, United Kingdom
Cooperation Partners
Dr. Joost Frieling; Dr. Morgan Thomas Jones
Ehemaliger Antragsteller
Dr. Jack Longman, until 3/2023
