Project highlights

  • Examining the influence of forces that determine the links between mantle and surface topography, and such features as development of subsidence and/or crustal uplift
  • 3D-numerical modelling using high performance computing, coupled with high-resolution seismic studies
  • Holistic approach looking to combine landscape evolution, geodynamics, and geophysics

Overview

This study will examine the role large-scale, global, mantle convection patterns might play on the long-term development of the Earth’s landscape, versus higher-resolution, localised studies that focus on features of basal architecture of the lithosphere, or presence of subducted slabs (e.g. Kaislaniemi & van Hunen 2014). Much of the debate around long-term landscape evolution, centres around lithospheric response to dynamics of the mantle beneath, versus the architecture of the lithosphere itself, or its history of loading or heating (e.g. Wheeler & White, 2002).

Both geophysical and numerical studies on global mantle structure reveal broad-scale convection patterns that show the flow of mantle beneath plates (e.g. Barry et al., 2017), but such studies do not include higher resolution details, such as asthenospheric interactions with the irregular base of the lithosphere, or localised disrupted flow patterns around downwelling slabs (e.g. Xu & Zhao, 2009; Zahirovic et al., 2016). Nor do they take account of dynamics within the lithosphere, such as basin development or regions of uplift.

This project will look at three contrasting regions, which characterise different complexities of flow regimes within the shallow mantle: east Africa – an intraplate setting dominated by a large-scale mantle upwelling and lacking subducted slabs within the shallow mantle; south-east Asia – an area dominated by the complex interaction of downgoing slabs and ongoing subduction; and central Asia – an intraplate area with no obvious large-scale plume or active subduction but has slabs deep within the upper mantle from former subduction events (Figure 1).

All these areas have a wealth of information about the nature of the landscape development, with information about the timing and extent of basin development, regions of uplift, details of distribution of magmatism deriving from the mantle, and detailed geophysical constraints on the architecture of the lithosphere. This project will examine how much the presence of slabs influences local mantle convection patterns over global patterns. How much does a mantle plume upwelling influence localised flow at the base of the lithospheric mantle? And how much does the resultant mantle flow influence the evolving landscape above it, with development of basins or upland areas?

CENTA Flagship

This is a CENTA Flagship Project

Host

University of Leicester

Theme

  • Dynamic Earth

Supervisors

Project investigator

  • Dr Tiffany Barry, University of Leicester

Co-investigators

  • Dr Stewart Fishwick & Dr Victoria Lane, University of Leicester

How to apply

Methodology

The project will investigate different-scales of influences on landscape evolution, using 3D mantle convection modelling available with open-sourced code, ASPECT (e.g. Kronbichler et al., 2012). Into the models, parameters from geophysical studies and plate models will be embedded, to impose different thicknesses of the lithospheric mantle, along with upper mantle structure, and broad-scale flow regimes. In this work you will focus on the uppermost asthenospheric/ lowermost lithospheric mantle to constrain velocity variations related to changes in lithospheric structure.

Part of this process will be to undertake improvements in surface wave models from seismic tomography data and receiver function studies to add detail to lithospheric form and therefore details for 3D-numerical models. Using these well-defined parameters and conditions, you will undertake numerical models using ALICE (University of Leicester’s high performance computing facility) to test scenarios of heat, melt, and landscape form and assess results against what we know from present day measurements.

The project will be developed in collaboration with the Geodynamic Team at Halliburton and will suit a student with a strong geophysics degree/background. It is an ideal project if you are interested in large-scale geodynamic and tectonic processes, enjoy 3D visualisations, and are willing to learn how seismology can be used as a tool to investigate fundamental questions about how the mantle and lithosphere interact. You should have an interest to learn linux and command line use of high performance computing, even if you do not have experience of this at the moment.

Training and skills

Training will be developed in: seismic observations, receiver function analysis and coding (including python and linux). Additionally, the successful student will gain training and experience in using high performance computing (HPC), and open sourced code ASPECT (no prior knowledge of this is required). A good level of numeracy and geophysical background will be enhanced through use and testing of tomographic models and survey data of lithospheric structure. Training will be provided at UoL and Halliburton for developing geodynamic models and development of landscape evolution models.

Partners and collaboration

The successful applicant will work with the geodynamic team at Halliburton, who will be involved in project design and execution throughout, and with whom you will learn how to apply geodynamic modelling to the company’s industrial applications, e.g. application of finite element models to thermal models and high-resolution structural models of the crust, plus use of digital elevation models in surficial expressions of topography. This work will build on techniques learnt through the PhD research, but applied at a range of different scales. Halliburton is one of the world’s largest providers of products and services to the energy industry, working globally in more than 80 countries. It helps its customers maximise the value of a reservoir, throughout the lifecycle of operations.

 

Further details

Please visit the University of Leicester website for application guidance:

https://le.ac.uk/study/research-degrees/funded-opportunities/centa-phd-studentships


This is a CENTA Flagship Project

These have been selected because the project meets specific characteristics such as CASE support, collaboration with our CENTA high-level end-users, diversity of the supervisory team, career development of the supervisory team, collaboration with one of our Research Centre Partners (BGS, CEH, NCEO, NCAS) or student co-designed project. These characteristics are a CENTA priority. Studentships associated with Flagship projects will be provided exactly the same level of support as all other studentships.

Possible timeline

Year 1

The successful candidate will begin examining seismological models and receiver function tests to establish lithospheric variability and/or potential thermal anomalies. 2D-model tests will look at variations in convection patterns resulting from steps in lithospheric thickness and barriers within the upper mantle, building up to simple box model tests.

Year 2

Real world architecture from the three contrasting regions will be built into 3D box models, working towards incorporation of plate motion histories of how plates and slabs have evolved through time, and digital elevation models of landscape form.

Year 3

Full 3D spherical models, incorporating plate motion histories will be used to examine toroidal flow patterns versus triggered responses to lithospheric features.

You will be supported to attend national and international conferences, as well as engage in international hackathons and networking events.

Further reading

Bagley, B. and Nyblade, A., 2013, ‘Seismic anisotropy in eastern Africa, mantle flow, and the African superplume’, Geophysical Research Letters, 40, pp. 1500-1505.

Kaislaniemi, L., and van hunen, J. (2014) ‘Dynamics of lithospheric thinning and mantle melting by edge-driven convection: application to Moroccan Atlas mountains’, Geochemistry, Geophysics, Geosystems, 15, pp. 3175-3189.
Kronbichler, M., Heister, T., and Bangerth,W. (2012) ‘High accuracy manle convection simulation through modern numerical methods’, Geophysical Journal International, 191, pp. 12-29.

Wheeler, P. and White, N. (2002), ‘Measuring dynamic topography: an analysis of Southeast Asia’, Tectonics, 21, doi.org/10.1029/2001TC900023.

Wu, J., and Suppe, J. (2017), ‘Proto-South China Sea plate tectonics using subducted slab constraints from tomography’, Journal of Earth Science, 10.1007/s12583-017-0813x.

Xu, P. and Zhao, D. (2009), ‘Upper-mantle velocity structure beneath the North China craton: implications for lithospheric thinning’, Geophysical Journal International, 177, pp. 1279-1283.

Zahirovic, S., Matthews, K.J., Flament, N., Müller, R.D., Hill, K.C., Seton, M., Gurnis, M. (2016), ‘Tectonic evolution and deep mantle structure of the eastern Tethys since the latest Jurassic’, Earth Science Reviews, 162, 293-337.

COVID-19

The project does not have an overseas fieldwork component to it, and can be entirely undertaken within the UK. As the project is computer-based, we do not foresee any issues related to the pandemic.

Collaboration with Halliburton can be facilitated through online meetings, as can all regular supervisory meetings.