Understanding variability in Earth’s climate and magnetic field using new archives from the Iberian Margin

Dr Chuang Xuan, Paul Wilson, OES; David Hodell, Cambridge

Marine sediments from the west Iberian Margin off the coast of Portugal offer exceptional opportunities to build high-fidelity and detailed (millennial scale) records of Earth’s past climate change. Previous studies demonstrate that these records can be unambiguously correlated to polar ice core records from both Greenland and Antarctica and used to study detailed marine-ice-terrestrial linkages. Previous studies also show that Iberian Margin sediments preserve high-fidelity information on the Earth’s past magnetic field directions and intensity, and that the magnetic properties of the sediments clearly record millennial- and orbital-scale climate variability.

You will work on new long and continuous sediment archives recovered during International Ocean Discovery Program (IODP) Expedition 397 (Iberian Margin Palaeoclimate). You will use these sedimentary records to shed new light on fundamental shifts in Pliocene-Pleistocene climate, such as the intensification of northern hemisphere glaciation, the mid-Pleistocene transition, and the Great Pleistocene Ice Ages. You will also develop new understanding of fundamental geophysical processes, such as the dynamics and causes of geomagnetic direction (e.g., polarity reversals and excursions) and intensity changes, and their possible connections to past climate change.



IODP Expedition 397 drilling will extend the remarkable sediment archive from the west Iberian Margin back to about 5 million years ago. You will study sediment archives collected during the expedition in this project. A suite of palaeomagnetic and environmental magnetic 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 and environmental magnetism laboratories. Data will be collected at high resolution to define magnetic polarity stratigraphy, estimate changes in Earth’s magnetic field strength and direction, and reconstruct down-core magnetic particle composition, concentration, and grain size variations that are sensitive indicators of palaeoenvironmental changes. These data will be used in combination with other biostratigraphic, geochemical, and physical property data (e.g., stable and radiogenic isotopes, X-ray fluorescence, sediment grain size), to precisely date the sediment archives, reconstruct the chain of events, underlying causes, and consequences of global and regional palaeoclimate and palaeomagnetic changes during the last few million years of Earth’s history. 


University of Southampton

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted in the School of Ocean and Earth Science.

Through the project, there will be opportunities to work together with a large group of international scientists collaborating with the supervisory team including the IODP Expedition 397 science team and gain experience sampling sediment cores at the overseas IODP Core Repository. Travel to international scientific meetings to present project results is encouraged and supported. Project-specific training includes:

  • Sampling and working with scientific ocean drilling cores and datasets
  • State-of-the-art analytical training in world-class laboratory facilities
  • Stratigraphic correlation and dating of marine sediment cores
  • Palaeomagnetic, and rock and environmental magnetic analyses of sediment samples
  • Geochemical analyses and X-ray fluorescence core scanning
  • Integration and interpretation of multi-proxy datasets from marine sediment cores for palaeomagnetic, palaeoceanographic and palaeoclimate reconstructions
  • Managing and processing large volumes of research data and application of advanced quantitative analysis techniques such as signal correlation and tuning, spectral analysis, and time-series analysis


Eligibility & Funding Details: 

Please see https://inspire-dtp.ac.uk/how-apply for details.


Background Reading: 

Hodell, D., Crowhurst, S., Lourens, L., Margari, V., Nicolson, J., Rolfe, J. E., Skinner, L. C., Thomas, N., Tzedakis, P. C., Mleneck-Vautravers, M. J., and Wolff, E. W., 2022. A 1.5-Million-Year Record of Orbital and Millennial Climate Variability in the North Atlantic, Clim. Past Discuss. [preprint] in review. https://doi.org/10.5194/cp-2022-61


Nichols, M. D., Xuan, C., Crowhurst, S., Hodell, D. A., Richter, C., Acton, G. D., and Wilson, P. A., 2020. Climate-Induced Variability in Mediterranean Outflow to the North Atlantic Ocean During the Late Pleistocene: Paleoceanography and Paleoclimatology 35, no. 9. https://doi.org/10.1029/2020PA003947


Xuan, C., Channel, J. E. T., and Hodell, D. A., 2016. Quaternary magnetic and oxygen isotope stratigraphy in diatom-rich sediments of the southern Gardar Drift (IODP Site U1304, North Atlantic): Quaternary Science Reviews 142, 74-89. https://doi.org/10.1016/j.quascirev.2016.04.010