The evolution of the interior of the Earth and solid planets

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My research interest is the thermal evolution of terrestrial planets and specifically planetary mantle and core heat exchange. Convection in planetary mantles is responsible for volcanism, seismicity and orogenesis. It influences a planet's topography and gravitational field, the magnetic field, the formation of mineral deposits and, in Earth's case, drives plate tectonics, continental drift, affects climate and influences cycles of biological evolution. To understand Earth's evolution, it is instructive to study other terrestrial bodies that are composed from the same materials. Rocky bodies throughout the solar system, as well as those detected orbiting more distant stars, provide a long list of puzzling questions: why does the Earth feature plate tectonics while other planets in the solar system do not; could planets elsewhere exhibit plate tectonics; what role does the early history of a planet have in determining whether it will achieve surface mobility; how does interior structure and heterogeneity affect cooling and how do some small moons remain geologically active? To address these issues I'll work with students and experienced collaborators using models that allow for calculations of the evolution of planetary mantle convection. Due to the very different time scales on which motions in planetary cores evolve versus the convective motion in the mantle, modelling mantle convection is not contingent on modelling core convection. Rather, the most common approach is to treat the core as a rapidly mixing reservoir of heat providing a constant temperature at the base of the mantle. Although this approach is well supported for many modelling studies it implies the modelling of a non-evolving planet, if the system is not able to cool. The research plan described here will feature a focus on investigating the influence of heat loss from the core and transitions in regimes as planetary mantles cool. The related projects will utilize tested open source computing tools and provide short term projects for several M.Sc. and senior undergraduate students. A more time-demanding aspect of this line of research will be investigations of the effect of mantle compositional heterogeneity on core cooling. A consensus has formed in the past decade that the lower mantle of the Earth shrouds two large seismically distinct provinces situated atop the core-mantle boundary. The nature of these provinces remains contentious but a possible compositional origin is a leading hypothesis. Such a component in the deep mantle would be an important influence on heat flow from the core due to a thermal blanketing effect. However, the formation, durability and mobility of such features in a cooling planet is not understood. I will work with new PhD students who will investigate the influence of deep mantle heterogeneity on core cooling and the influence of rheology, core size and surface properties on the cooling of the Earth and other terrestrial planetary objects.