HR: 1340h
AN: T23B-0576    [Abstracts]
TI: Applications of Crustal Velocity Models to Tectonic Problems
AU: * England, R W
EM: rwe5@le.ac.uk
AF: Department of Geology University of Leicester, University Rd, Leicester, LE1 7RH United Kingdom
AU: Kelly, A
EM: ak132@le.ac.uk
AF: Department of Geology University of Leicester, University Rd, Leicester, LE1 7RH United Kingdom
AU: Maguire, P K
EM: pkm@le.ac.uk
AF: Department of Geology University of Leicester, University Rd, Leicester, LE1 7RH United Kingdom
AU: Chadwick, A
EM: rach@bgs.ac.uk
AF: British Geological Survey, Keyworth, Nottingham, NG12 5GG United Kingdom
AU: Pharaoh, T
EM: tcp@bgs.ac.uk
AF: British Geological Survey, Keyworth, Nottingham, NG12 5GG United Kingdom
AB: A velocity model has been produced for NW Europe using available 2-D wide-angle seismic profiles. By using these data estimates of velocity structure and depth to major velocity transitions can be determined. By extrapolating the velocity structure between adjacent profiles it is possible to produce a 3-D model of the velocity structure of the crust, and by simple translation a model of the density variations. This model is being used to study a variety of tectonic problems. It has been used to examine the relationship between crustal thickness and topography. This analysis of the data demonstrates that there must be significant lateral changes in the density of the upper mantle (previously inferred from modelling of gravity data) in order to support the observed topography. Thus it is possible to accurately determine the degree of continental dynamic support. The model reveals the extent of magmatic underplating beneath the continental margin of NW Europe and reveals a major discrepancy between estimates of exhumation and the distribution and amount of magmatic underplating. From this study it is possible to show the extent to which the velocity/density structure controls the topography and the present surface geology and to make predictions about the future evolution of surface elevation.
DE: 9335 Europe
DE: 8105 Continental margins and sedimentary basins
DE: 8110 Continental tectonics--general (0905)
DE: 7205 Continental crust (1242)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting