Project Details
Projekt
Establishing a magnetofossil-based paleoclimate proxy across the Eocene–Oligocene Transition in the South Pacific and the South China Sea (IODP Sites U1553 and U1501)
Applicant
Yang Zhang, Ph.D.
Subject Area
Geology
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 467394398
The Eocene–Oligocene transition (EOT) marks a profound paleo-oceanographic change and paleoclimate cooling at ~34 Ma during the Middle Eocene to Early Oligocene that eventually led to a turnover from a greenhouse to an icehouse world; potential triggers include the shift in orbital configuration, opening of the Southern Ocean Gateway, and long-term decrease in atmospheric CO2. However, our understanding of the triggering mechanisms is limited, partly because oxygen isotope data that initially identify and define this global cooling event may be impacted by multiple environmental factors and are often easily altered due to diagenesis. Fossil biogenic magnetite of magnetotactic bacteria (MTB) provides a promising new proxy for such climatic shifts. Due to the MTB’s ability to intracellularly biomineralize magnetite of single domain grain sizes that are easily detected by magnetic measurements, magnetofossils have been recently used as prokaryotic biomarkers for suboxia and, potentially, marine productivity, nutrient availability, and organic carbon supply.Here I propose to investigate the occurrence of biogenic magnetite and its environmental implications across the E–O interval of sediments drilled during two International Ocean Drilling Program (IODP) Expeditions: Site U1553 and Site U1501. While most EOT studies are from low-latitude deep-sea cores, the recent IODP Expedition 378 to the South Pacific and IODP Expedition 367 & 368 to the South China Sea (on both of which I sailed as a paleomagnetist) recovered full sections of the EOT interval in the southern high latitude and in a marginal setting, respectively. Both are key location to complete our understanding of the EOT by employing thorough environmental magnetism.
DFG Programme
Infrastructure Priority Programmes
Co-Investigator
Professor Dr. Tilo von Dobeneck
