Institute of Geophysics and Tectonics (IGT) PhD Projects
Validating Models of Channel Flow, Ductile Extrusion and Exhumation
- the Greater Himalaya Slab, Everest Region
Supervisors: Dr Richard Phillips & Dr Geoff Lloyd (Leeds), Professor Mike Searle (Oxford)
Despite several decades of active research in the Himalaya, models to describe its evolution remain controversial. One favoured model, known as ‘Channel Flow’ suggests that flow of an active weak magmatic channel beneath Tibet and the High Himalaya can, in part, explain the tectonics and evolution of mountain building – a fundamental question in the Earth Sciences. Importantly, the Channel Flow model also suggests a strong link between tectonics, surface processes and climate, resulting in a new field of critical research that examines feedback mechanisms between the Asian Monsoon, erosion of the Himalaya and exhumation of the Himalaya frontal range.
The concept of channel flow is defined by fluid dynamics and is well developed. It is only within the last few years though that it has been taken up by geodynamicists to explain how orogenic belts, such as the Himalayan chain, may evolve. In order to critically examine the channel flow model this project aims to provide important microstructural and strain data by utilizing the new £1M scanning electron microscope (SEM) and electron microprobe (EMP) facilities within the School of Earth and Environment, University of Leeds. These data will also be used to characterize the seismic properties of the Greater Himalayan Slab, which will aid the geophysical identification of weak magmatic channels in active and inactive collisional orogenic belts.
North Face of Everest (Photo: Mike Searle ©)
Fieldwork will include one season in the Everest region collecting low-level samples from the Greater Himalayan Slab. Additional samples, taken in a vertical transect from Everest basecamp to its summit, have already been acquired. The project and fieldwork will involve collaboration with Prof. Rick Law (Virginia Tech, USA) who has many years of field experience in the Himalaya and the Everest region.
The student will utilize the School’s new SEM and EMP, which have unique capabilities of electron back scatter diffraction (EBSD) and high-resolution microprobe analysis, allowing:
- Quantification of strain and vorticity of ‘channel flow’ via EBSD;
- Determination of the seismic properties of a weak magmatic channel and comparison of this to geophysical datasets for Tibet and other collisional orogenic belts;
- Use of the dataset to interrogate the ‘channel flow’ model of the High Himalaya.
- Use of the dataset to examine the proposed feedback mechanisms between crustal evolution, the Asian Monsoon and erosion.
The student will join a growing and dynamic Tectonics research group within the School. Training will be provided in field mapping and structural analytical techniques, including use of the Schools’ new state of the art SEM/EBSD and microprobe. The student will also have an opportunity to present their research at international conferences (e.g. AGU-California).
Selected publications by supervisors and collaborators:
Law, RD; Searle, MP; Simpson, RL (2004) Strain, deformation temperatures and vorticity of flow at the top of the Greater Himalayan Slab, Everest Massif, Tibet, J GEOL SOC LONDON, 161, 305–320.
Law, RD; Searle, MP; Godin, L Eds (2006) Channel Flow, Ductile Extrusion and Exhumation in Continental Collision Zones. J GEOL SOC LONDON SPEC PUB, 268, 632 pp. ISBN: 978-1-86239-209-0.
Lloyd, GE; Butler, RWH; Casey, M; Mainprice, D (2009) Mica, deformation fabrics and the seismic properties of the continental crust, EARTH PLANET SC LETT, 288, 320-328.