Lead supervisor: Nicky White, Earth Sciences
Co-supervisor: David Al-Attar, Earth Sciences
Brief summary:
What could be of more fundamental importance than understanding how mantle dynamics affects the Earth's surface through space and time!
Importance of the area of research concerned:
Convective circulation of Earth's mantle generates dynamic topography at the surface which is expected to vary as a function of space and time. In recent years, considerable research effort has been targeted at predicting dynamic topographic patterns from the density structure of the mantle inferred from global seismic tomographic models. Unfortunately, these predictions disagree with limited, and mostly ocean-based, observations of dynamic topography. It is now opportune to re-examine the quantitative relationship between between dynamic topography, seismic tomography and mantle viscosity.
Project summary :
New measurements of dynamic topography through space and time will form the starting point of this project. These measurements represent an important missing piece of the puzzle in attempts to understand the way in which convective circulation of the mantle generates transient vertical motions at the surface. Dynamic topographic constraints will be be combined with seismic tomographic models and with simple assumptions about the variation of viscosity with radius. In this way, we will develop an improved understanding of the nature and influence of convective processes.
What will the student do?:
In the first stage of the project, spherical harmonic analysis will be used to analyze dynamic topography. The results will then be compared with predictive dynamic topographic models to assess their applicability. In the second stage, analytical predictive models of dynamic topography will be developed from seismic tomographic models and the parameter space of radial viscosity variation explored. The student will use these results to develop a fluid dynamic understanding of convectively driven vertical motions.
References - references should provide further reading about the project:
Hoggard, M.J., White, N. & Al-Attar, D., 2016. Global dynamic topography observations reveal limited influence of large-scale mantle flow. Nature Geoscience, vol. 9, 456-463.
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.
Richards, F.D., Hoggard, M.J., White, N. & Ghelichkhan, S., 2020. Quantifying the relationship between short‐wavelength dynamic topography and thermomechanical structure of the upper mantle using calibrated parameterization of anelasticity. Journal of Geophysical Research: Solid Earth 125 (9), e2019JB019062.
Applying
You can find out about applying for this project on the Department of Earth Sciences page.