Grant: Discovery Grants Program - Individual

The heat engine inside the rocky mantle below Earth's crust is characterised by the very large scale transport of mass and heat across vertical and horizontal distances of thousands of kilometres inside our planet. This continuous flow of hot rock, termed thermal convection, exerts forces which drive the horizontal 'drift' of the surface tectonic plates, generating deformations in the crust which are relaxed by large, often destructive earthquakes. These deep Earth forces also produce vertical displacements of the continents and ocean floor across distances of hundreds of metres, thereby producing relative sea level variations which have indundated large portions of continental interiors in the geologic past. These vertical movements can also change the external shape of the Earth to such an extent that they perturb its orbital inclination relative to the Sun and can thus affect the evolution of climate cycles on our planet. In this proposal we provide an ambitious and exciting series of new initiatives to directly model and predict the dynamical impact of mantle convection on these wide ranging surface processes which have shaped the evolution of Earth's surface environment over geological time spans. Through refinements of numerical convection codes which we are developing to reconstruct the evolution of Earth's interior in the geologic past, we will model fundamental dynamical processes affecting two continents in particular, North America and Africa, and these include: (1) dynamic surface topography and erosion; (2) (in)stability of coastal margins and sea level variations; (3) surface stress patterns and earthquake activity. Using these convection models we will also make detailed predictions of the global-scale changes of Earth's external shape and rotation variations over the past 60 million years, thus providing new insights on how mantle convection may affect Earth's palaeoclimate cycles. We will also seek to substantially improve our knowledge of the 3-D mantle structure by carrying out a new series of joint inversions of global seismic and convection data. These innovative investigations into the workings of the Earth System will be advanced by the participation and training of HQP and through multiple international collaborations which we will foster.