UCL Earth Sciences


Tomos Kempley

"Understanding the dynamical consequences of phase transformations within the Earth’s mantle: combining mantle flow and thermodynamic modelling to predict dynamic topography."

PhD project title:

Is Earth’s topography controlled by mantle thermodynamics?

Tomos Kempley
Project description:

The goal of the project is to explore the dynamical consequences of phase transformations that occur in the Earth’s mantle. The focus will be on geophysical observables including the geoid and dynamic topography.

The influence of mantle phase transformations on the geoid and dynamic topography has only been studied in passing, and their influence on the flow is understood only in general terms. Yet over the top 1000 km, to which dynamic topography is most sensitive, they are ubiquitous. Moreover, the sequence of phase transformations that occur in the upper mantle, and their associated density contrasts and Clapeyron slopes are now reasonably well constrained experimentally. I will test the hypothesis: can phase transformations substantially reduce the magnitude of predicted dynamic topography, leading to an understanding of this critical surface signature of mantle flow?

Properties will be studied via a combined effort of Stokes modelling of mantle flow, and thermodynamic modelling of mantle phase transformations, using existing software (spectral instantaneous flow and convection finite element codes for Stokes Flow and HeFESTo for thermodynamics). Predictions will be compared to satellite-derived gravity and topography fields.