Late Pleistocene Geomagnetic and Environmental Change in East Asia

Project Rationale:
Earth’s magnetic field is essential to life on our planet because of the protection it provides from solar wind and cosmic rays. Understanding the causes and consequences of geomagnetic change requires reliable records of the field with suitable temporal and spatial resolution and coverage. Beyond historical observations, marine sediments provide the main archive for reconstructing long and continuous past geomagnetic change. Existing records spanning the past ~10 thousand years have shown intriguing changes in the field structure over the East Asia. However, the lack of longer records from the region prevents us from answering some key research questions. For example, are these patterns persistent or transient over longer time periods?

Integrated Ocean Drilling Program (IODP) Expedition 346 recently recovered long sediment archives from the East China Sea and Japan Sea. Pilot work indicate these sediments are suitable for paleomagnetic reconstructions, and the environmental magnetic records can be related to Asian Monsoon variations. Taking this unique opportunity, you will build and exploit well-dated and absolute-value calibrated (through numerous interbedded ash layers) paleomagnetic and environmental magnetic records to decipher the causes and consequences of geomagnetic and environmental changes in the East Asia during the past few hundred thousand years (Late Pleistocene).


Methodology:
Continuous drillcore (u-channel) and bulk sediment samples collected from selected IODP Expedition 346 sites with high sedimentation rates (averaging 40-50 cm/kyr) and proven suitability for palaeomagnetic studies will be investigated in this project. A suite of palaeomagnetic measurements including natural and laboratory-induced magnetizations as well as sediment magnetic properties will be conducted using state-of-the-art in-house facilities at the University of Southampton Palaeomagnetism Laboratories. Scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analyses will be performed on bulk sediments or magnetic extracts to develop a detailed understanding of the nature of magnetic remanence in the sediments. Through collaboration with other IODP Expedition 346 scientists, sources of the numerous ash layers in the sediments will be traced, and existing paleointensity studies of the source area will be used to calibrate the sedimentary palaeomagnetic records. These data will be used in combination with other biostratigraphic, geochemical (e.g., stable and radiogenic isotopes, XRF), and physical property data (e.g., colour reflectance, density), as well as other well established globally distributed palaeomagnetic and environmental records, to develop a critical understanding of the causes and consequences of geomagnetic and environmental changes.

Training:
All doctoral candidates will enrol in the Graduate School of NOCS (GSNOCS), where they will receive specialist training in oral and written presentation skills, have the opportunity to participate in teaching activities, and have access to a full range of research and generic training opportunities. GSNOCS attracts students from all over the world and from all science and engineering backgrounds. There are currently around 200 full- and part-time PhD students enrolled (~60% UK and 40% EU & overseas).

The successful candidate will receive training in our world-class palaeomagnetism and palaeoclimate research facilities available at the University of Southampton’s Waterfront Campus at the National Oceanography Centre (NOC). You will learn novel methods for managing and processing research data and advanced quantitative analysis techniques such as signal correlation and tuning, spectral analysis, and time-series analysis. You will collaborate with a wide range of international scientists involved in IODP Expedition 346 studies and gain experience sampling IODP materials at oversea IODP Core Repositories. Travel to international scientific meetings such as EGU and AGU to present project results will also be encouraged and supported.