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E423: Linking landscape evolution with mantle processes in North Borneo (Lead Supervisor: Nicholas Rawlinson, Earth Sciences)

Supervisors: Nicholas Rawlinson (Earth Sciences) and Nicky White (Earth Sciences

Importance of the area of research:

It is well known that surface topography has a strong dependence on lateral variations in density in the crust and mantle lithosphere. However, there is also good evidence to show that flow in the mantle can induce transient surface deformation which leads to so-called dynamic topography. In post-subduction settings, magmatism, exhumation, rapid uplift and subsidence may all occur, but the mechanisms that drive these processes are unclear, and the relationship between surface and mantle dynamics is poorly understood. Since subduction termination is an integral part of the global subduction cycle, it is essential that improved models of this process are developed in order to better understand the evolution of continental margins.

Project summary:

North Borneo, featuring a range of distinctive surface features, including the 4100 m high Mt. Kinabalu, unusual circular basins and recently active off-shore fold and thrust belt, is an ideal place to study post-subduction processes. A joint onshore-offshore deployment of seismic instruments in 2018 will provide a new dataset capable of imaging the crust and upper mantle structure in detail. The goal of this project is to examine the geomorphology of North Borneo in order to understand how the landscape has evolved in a post-subduction setting, and link the results with those from seismic imaging and geodynamic modelling of mantle flow.

What the student will do:

The student will carry out fieldwork in North Borneo in order to estimate the spatial variation of uplift rates throughout the Neogene. This will include dating sediments and examining drainage pattens. These results will be compared with crustal and lithospheric mantle velocity models in order to isolate contributions from mantle flow processes. 2-D and 3-D geodynamic modelling, informed by seismic imaging results, will be used to link mantle flow processes (e.g. induced by slab break-off, lithospheric delamination, gravitational instability of lithospheric root)  with observations of surface uplift. During the fieldwork, the student may also be involved in the deployment and servicing of seismic stations throughout North Borneo, including in the Maliau Basin Conservation Area, otherwise known as Sabah's  €œLost World €.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Czarnota, K., Roberts, G.G., White, N. & Fishwick, S. 2014. Spatial and temporal patterns of Australian dynamic topography from river profile modeling. Journal of Geophysical Research, vol 119, pp. 1384-1424.

Hall, R. 2013. Contraction and extension in northern Borneo driven by subduction rollback. Journal of Asian Earth Sciences, vol 76, pp. 399-411.

Magni, V., Allen, V. M. B., van Hunen J. and Bouilhol P. 2017. Continental underplating after slab break-off. Earth and Planetary Science Letters, vol 474, pp. 59-67.

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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