The London Basin Forum: Basin Structures
- The London Basin covers approximately 15,000 km2
- Its origins lie in Palaeozoic collision of Avalonia with the rest of Europe and North America and although an intraplate area from then on, its evolution has been dictated by the complex interactions between Europe, North America and Africa.
- It is probably the most intensively observed region of Earth, with 78,000 boreholes sunk in Greater London alone, yet its structure is still poorly understood. Until recently it was believed to be a simple syncline; it is now known to be a fault-controlled extensional basin that is still modestly active.
- Working closely with Prof. John Cosgrove (Basement Structures), my role on the London Basin Forum steering group is to deduce the tectonic history of the basin and analyse the structures within its sedimentary fill.
Envision: understanding why our most earth-like neighbour is so different
- While Earth sized planets are being discovered around other stars, Venus, the planet most similar in size to Earth, remains an enigma. How and why did Earth and Venus evolve so differently?
- EnVision is a proposed ESA medium class mission to determine the nature and current state of geological activity on Venus, and its relationship with the atmosphere, to understand how Venus and Earth could have evolved so differently.
- Orbiting at 258km, EnVision will use a world-leading European phased array synthetic aperture radar, VenSAR, to obtain global topography at 27m and imagery at up to 1m resolution, and us InSAR to detect changes of < 1cm/yr.
- It will use a subsurface radar sounder to obtain profiles of the upper few hundred metres, and an IR mapper and spectrometer to detect volcanic eruptions.
- EnVision will return more than 1TB of new data, revolutionising our understanding of Venus and how it came to be so different.
Intraplate Processes and the Neotectonics of Great Britain
- Why do continental interiors exhibit tectonic processes from apparently distant sources and how are those stresses transmitted?
- What controls the magnitude and timing of fault movements in continental interiors and what are their engineering implications?
- One of the problems in addressing these questions has been that the rates of intraplate movements have been too small to measure.
- Fortunately, a series of fixed trigonometric pillars were installed from 1936 onwards across Great Britain and precisely measured; modern GPS measurements from those same pillars reveals discrepancies indicative of decades of slow intraplate movements.
- Analysis of these data and correlation with recent satellite and seismic observations are providing new insights into neotectonic processes in Great Britain and more generally intraplate processes worldwide.
Plate Tectonics on Buoyant Lithospheres: subcrustal plate tectonics on Venus
- Venus has a buoyant lithosphere because of its high surface temperature; can a planet maintain thermal equilibrium in such circumstances?
- Fortuitously, its high surface temperature causes a weak layer in the lower crust (~5-8 km depth) that decouples the underlying mantle lithosphere, allowing it to decouple and slip independently.
- Unencumbered by a low density crust, the mantle lithosphere is able to form, spread and subduct below the crust as our ocean plates do below the sea, despite its high temperature.
- Observations across the major rift systems on Venus indicate a network of 55-65,000 km of spreading ridges diverging at rates 5 to 10 times those on Earth, sufficient for Venus to maintain thermal equilibrium.
- Furthermore, analysis of certain mountain belts indicate that they may overly subduction zones, while major strike-slip systems provide conclusive evidence for plate-like movements on Venus.
Venus Geophysics, ESA's Alpbach Summer School, Austria, 2014
The Geology of Venus: new insights and future prospects, Indian Space Research Organisation, Bangalore, India, 2014
GCG Annual Field Trip, Geotechnical Consulting Group, Field trip to Minehead and Cheddar (20-22 May 2011), 2011
Move: Applications in Ground Engineering Research and TeachingMidland Valley Move 2013 User Meeting, Midland Valley Exploration, Our Dynamic Earth, Edinburgh, 2013
Research Student Supervision
Bischoff,C, CDT Civil Engineering: London Inversion
Newman,TG, P25475 Confined Space Hypoxia