Lead supervisor: Nicky White, Earth Sciences
Co-supervisor: John Maclennan, Earth Sciences
Brief summary:
An imaginative and exciting project that combines the study of sedimentary and igneous rocks, Icelandic mantle plume dynamics and linked climate change, all with a strongly expeditionary flavour!
Importance of the area of research concerned:
The difficulties of understanding the dynamics of mantle plumes through space and time can be surmounted by analysing basaltic magmatism. This inference is based upon a clear correlation between present-day magmatism and convectively-driven regional uplift. Furthermore, it can be shown that there is a quantitative relationship between the volume and composition of igneous rocks, and the size and shape of convective upwellings. Physical models, which have been used to advance our understanding of the links between composition, volume, asthenospheric temperature and lithospheric thickness, can be applied throughout the Phanerozoic record in order to analyse the spatial and temporal pattern of dynamic topography.
Project summary :
The Icelandic mantle plume is the largest convective upwelling on Earth. It is also positioned at a key oceanographic gateway which controls the overflow of North Atlantic Deep Water (NADW) that plays a vital role in moderating the Meridional Overturning Circulation (MOC) and therefore palaeoclimate. This plume is unusual in that it is transected by the mid-oceanic ridge which acts as a linear window or 'sampler' of plume activity. As a result, time-transgressive V-shaped ridges and troughs have formed on oceanic crust. In July-August 2021, the International Ocean Discovery Program Expedition 395 drilled boreholes into these V-shaped ridges and troughs. A further drilling expedition is scheduled for July-August 2023. In this exciting project, basaltic rocks from these expeditions will be analyzed with a view to developing an understanding of this enormous plume.
What will the student do?:
The student will exploit newly acquired, and soon to be acquired, deep-sea borehole samples of sedimentary and basaltic rocks from the North Atlantic Ocean south of Iceland. Geochemical and other analyses will be carried out to determine major, trace and rare earth element concentrations. This database will be used to develop an understanding of depth, degree and temperature
of melting. In this way, a new understanding of temporal plume dynamics will be developed and linked with palaeoclimate observations. There will also be an opportunity to participate in a scheduled deep-sea expedition in 2024.
References - references should provide further reading about the project:
Poore, H., White, N., & Maclennan, J., 2011. Ocean circulation and mantle melting controlled by radial flow of hot pulses in the Iceland plume. Nature Geosciences, vol. 4, DOI:10.1038/NGEO1161
Parnell-Turner, R., White, N., Henstock, T., Murton, B., Maclennan, J. & Jones, S., 2014. A continuous 55-million-year record of transient mantle plume activity beneath Iceland. Nature Geoscience 7 (12), 914-919.
Ball, P.W., White, N.J., Maclennan, J. & Stephenson, S.N., 2021. Global influence of mantle temperature and plate thickness on intraplate volcanism. Nature communications 12 (1), 1-13.
Applying
You can find out about applying for this project on the Department of Earth Sciences page.