Nicky White

Research Area

Vertical Motions, River Drainage and Mantle Convection

It is generally accepted that convective currents within the Earth's mantle drive plate motion. However, despite theoretical and observational advances, our understanding of the spatial and temporal evolution of these currents remains fragmentary. The Earth's stratigraphic record is a potentially rich source of information about this process since convective upwelling and downwelling should produce measurable vertical displacements at the surface. These displacements should influence drainage patterns and the redistribution of sediment: the challenge is to extract useful and accurate constraints. To date, we have concentrated on the fringes of the North and South  Atlantic oceans whose stratigraphic evolution has been moderated by mantle convective processes over the last 60 million years. Our results allow us to map the planform of upwelling through time. We have also analyzed continents such as Africa where many significant geological features are thought to be maintained by the convective pattern. Africa is drained by a small number of large rivers whose long-term sedimentary fluxes are primarily controlled by catchment size and relief. Changing flux patterns may help to measure temporal and spatial changes in upwelling and downwelling. The geometry of coastal shelves is particularly sensitive to modest displacements. Measurements of denudation along the West African shelf have been used to reconstruct Neogene vertical motions. Our results have global implications for oceanography and climate.

Project Interests

I am especially interested in three specific areas within which projects can be developed.  First, analysis of the development of the Icelandic Plume which is the largest on Earth using recently acquired IODP drill cores and geophysical surveys. Secondly, exploiting time-lapse volumetric acoustic imaging of oceanic circulation with a view to improving our fluid dynamical understanding of physical oceanography. Thirdly,  developing and applying globally observed inventories of mantle dynamic topography and linking these observations to basaltic volcanism.