Supervisors: Nicky White (Earth Sciences), Mark Hoggard (Earth Sciences) and Alexander Bump (BP Exploration)
Importance of the area of research:
It is generally recognized that a signiﬁcant fraction of topography and bathymetry is maintained by convective circulation of the Earth’s mantle. This fraction is referred to as dynamic topography and its variation across the globe and through geological time contains important clues about convective circulation.
In the oceanic realm, it is straightforward to identify and measure dynamic topography. Adjacent to the South American shelf, dynamic topography varies with an amplitude and wavelength of ±1 km and 1000 km, respectively. This variation aﬀects the geology and geomorphology of the Brazilian coastline. For example, emergent Holocene marine terraces and exposed Neogene marine sediments occur around the edge of the Borborema Plateau, which is probably a convectively uplifted dome.
What the student will do:
The spatial variation of uplift rate along the Brazilian coastline will be determined by dating marine terraces and sedimentary rocks. This variation will be analyzed in conjunction with dynamic topographic measurements from seismic and well data along the adjacent oceanic margin. Drainage analysis and river proﬁle modelling will be carried out for a region encompassing the Borborema Plateau. Geological and geomorphological observations will be integrated with ongoing studies of basaltic volcanism which peppers the plateau. Results will be compared with crustal velocity models determined from passive seismic monitoring. Evolution of the region will be compared with similarly formed domes elsewhere (e.g. Angolan Dome of West Africa).
Al-Hajri, Y., White, N., & Fishwick, S., 2009. Scales of convective support beneath West Africa. Geology, 37, 883–886.
Poore, H., White, N. & Maclennan, J., 2011. Oceanic circulation and mantle melting controlled by radial ﬂow of hot pulses within Icelandic plume. Nature Geosciences, 4, doi:10.1038/ngeo1161.
Winterbourne, J., White, N. & Crosby, A., 2014. Accurate measurements of residual topography from the oceanic realm. Tectonics, 33, 982–1015, doi:10.1002/2013TC003372
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