Centre for Lithospheric Dynamics
The focus of the Centre for Lithospheric Dynamics is to gain a deeper understanding of the geological processes that cause mountain building and basin formation.
The movements in the upper mantle and plates – the lithospheric plates – is at 100-200km deep. These plates deform when they interact, despite appearing rigid, and are responsible for the deformation that built the Alpine Himalayan Belt, moving at 10s of mm per year. These movements, though generally imperceptible, eventually result in destructive earthquakes at irregular intervals typically measured in centuries or millennia.
The understanding of where and how these deformations occur is just the first step in an evaluation of earthquake hazard, so understanding the earthquake cycle is an important theme for this research centre.
This research will be advanced by 3D computer models of the deformation, supported by seismic investigations at a regional scale, and geodetic measurements of surface displacements. The computer models must represent movement of faults in the upper 20 km or so, as well as viscous creep in the deeper levels, and they must ensure that the principles of mass, momentum and energy conservation are respected. Such models also have application in assessment of volcanic hazard. In both cases measurement of Earth surface displacements to a relative accuracy of a few mm are essential to an understanding of stress and movement within the lithosphere.
Lithospheric deformation sustained over periods of millions of years results in the development of mountain ranges (the classic example is the Himalayan Range) where the movements are convergent, and the crust is thickened. Some sedimentary basins develop in these convergent orogens, but most occur where the plate is extended and thinned (as for example has occurred in the South China Sea). Sedimentary basins are the primary reservoirs for naturally occurring hydrocarbons so there is a strong resource-oriented motivation for studying the way in which they have developed. In particular, models of the thermal evolution of a basin are an essential element in hydrocarbon exploration since the requirements for thermal maturation of a resource depend primarily on the evolution of temperature with time and depth in the sedimentary strata.
Apart from a focus on hydrocarbon exploration which could be pursued via collaborative projects with the Centre for Reservoir Geophysics, sedimentary basins may be important as a water resource, for geothermal energy, and potentially for sequestration of carbon dioxide, so models of the development of these basins are an important tool in understanding the way in which such resources can be exploited.