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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities
Brief summary: 
Use marine geophysical and geological datasets to examine the architecture of two major components of the West Antarctic margin and constrain the processes involved in their construction: (i) the Belgica Trough Mouth Fan, and (ii) large, deep-sea sediment drifts on the continental rise.
Importance of the area of research concerned: 
The West Antarctic Ice Sheet has advanced and retreated across its adjacent continental margin many times during the Neogene and Quaternary, possibly collapsing entirely during the last interglacial. This has produced thick sequences of glacial and glacially-influenced sediments that contain long-term records of ice-sheet history, Southern Ocean circulation and climatic change (e.g. Hernández-Molina et al., 2017). However, there is significant variability in the gross morphology and internal architecture of the margin and unravelling the factors dominating sediment delivery, and their relationships with climatic forcings, remains challenging. These factors include ice-sheet advance/retreat cycles that control the periodicity of sediment delivery, basal meltwater fluxes, drainage basin geology, and dominant transport mechanisms. Inferences drawn from understanding this unique submarine glacial landscape can provide insights into the growth and decay of continental ice sheets and ice-ocean-climate interactions. Knowledge of these connections is critical for our understanding of the vulnerability of the modern Antarctic Ice Sheet to climatic change.
Project summary : 
This project will use marine geophysical and geological datasets to study two major yet understudied components of the West Antarctic margin: (i) the Belgica Trough Mouth Fan (Dowdeswell et al., 2008), and (ii) large, deep-sea sediment drifts on the continental rise (Rebesco et al., 1996). Both of these contain predominantly glacially-sourced material but reflect different formation and transport mechanisms that are related to different ice/ocean/climatic forcings and different disposition relative to ice drainage basins. The fan primarily reflects the activity of a grounded ice sheet on the outer shelf whereas the drifts are constructed of fine-grained components from turbidity currents that became entrained in a deep contour current flowing along the margin. Using high-resolution multichannel seismic lines from four sediment drifts and across the fan, integrated with swath bathymetry.
What will the student do?: 
The student will be involved with the processing and analysis of marine geoscientific datasets including reflection seismic profiles, seafloor bathymetry and core sedimentology. This will involve detailed morphological measurements and seismic analyses (amplitude distribution, bottom simulating reflectors, sequence mapping) to determine the evolution of both the fan and the drifts. This will be integrated with the surface morphology of these features revealed by swath bathymetry, to examine erosion and transport processes at a variety of scales from the individual drift flanks to full ocean margin (shelf-slope) transects. There is potential for the student to get involved in numerical modelling of glacial sediment transport/delivery and to use their results from marine geophysical data to test model outputs.
References - references should provide further reading about the project: 
Dowdeswell, J.A., Ó Cofaigh, C., Noormets, R., Larter, R.D., Hillenbrand, C.-D., Benetti, S., Evans, J. & Pudsey, C.J., 2008. A major trough-mouth fan on the continental margin of the Bellingshausen Sea, West Antarctica: the Belgica Fan. Marine Geology, vol. 252, pp. 129-140. DOI:10.1016/j.margeo.2008.03.017.
Hernández-Molina, F.J., Larter, R.D. & Maldonado, A., 2017. Neogene to Quaternary stratigraphic evolution of the Antarctic Peninsula, Pacific Margin offshore of Adelaide Island: Transitions from a non-glacial, through glacially-influenced to a fully glacial state. Global and Planetary Change, vol. 156, pp. 80–111. DOI:10.1016/j.gloplacha.2017.07.002.
Rebesco, M., Larter, R.D., Camerlenghi, A. & Barker, P. F. 1996. Giant sediment drifts on the continental rise west of the Antarctic Peninsula. Geo-Marine Letters, vol. 16, pp. 65-75. DOI:10.1007/BF02202600.
You can find out about applying for this project on the British Antarctic Survey (BAS) page.
Dr Robert Larter
British Antarctic Survey Graduate Administrator