Geophysics

We use geophysics to study rock bodies from the fine-scale (seismic emissions during rock deformation laboratory experiments) to structures of basins on land and in the oceans. We use industrial and academic reflection seismic data calibrated with borehole- and geochemical datasets, outcrop- and satellite observations to investigate continental margin-, epicontinental- and exhumed basins to unravel their evolution, palaeogeography, palaeoclimate, sedimentary processes, salt tectonic processes, glaciogenic records, source to sink dynamics, igneous and sedimentary intrusions and extrusions, and fluid flow phenomena. Focus areas include North Sea, North and South Atlantic Margins, Oceania. Within the oceans, our focus has mainly been on the Azores and Red Sea areas (volcanic, tectonic and sedimentary processes). Marine geophysical work is based on potential fields (gravity, magnetics), though primarily seabed-imaging sonars. Onshore geophysical methods (seismic, gravity, magnetics and electrical resistivity) have recently been used to study the structural geometry of sedimentary basins and fault zones in S.E. Spain and the Mam Tor landslide in Derbyshire. Laboratory studies have been and are used to measure frictional properties of fault rocks, acoustic wave propagation and effects of pore fluids in sandstones and shales, and in particular to relate these properties to pressure-dependent rock matrix permeability and hydraulic transmissivity of cracks. High temperature experiments on minerals are used to investigate the defect chemistry of the mineral structure and its influence on crystal plasticity. Some of these deformation experiments are performed at ISIS neutron facility (Harwell Campus, near Oxford).