HR: 0830h
AN: T31F-0895    [PDF]
TI: Postcollisional Deformation of the Alps: Results From Numerical Modeling
AU: * Jimenez-Munt, I
EM: i.jimenez-munt@ucl.ac.uk
AF: Dep. of Earth Sciences, University College London, Gower Street, London, WC1E 6BT United Kingdom
AU: Garcia-Castellanos, D
EM: gard@geo.vu.nl
AF: Tectonics Dept., Faculty of Earth Sciences, Vrije Universiteit of Amsterdam, De Boelelaan, 1085, Amsterdam, 1081HV Netherlands
AU: Negredo, A M
EM: anegredo@fis.ucm.es
AF: Dep. of Geophysics, Faculty of Physics, University Complutense of Madrid, Av. Complutense, Madrid, 28040 Spain
AU: Platt, J
EM: john.platt@ucl.ac.uk
AF: Dep. of Earth Sciences, University College London, Gower Street, London, WC1E 6BT United Kingdom
AB: In this work we present the results of a numerical modeling applied to study the large-scale deformation induced in the Alpine region by the Africa-Eurasia convergence during the postcollisional phase (last 40 Ma). We use the thin sheet approach which assumes a vertically averaged rheology and permits us to simulate the lithosphere as a thin viscous layer subjected to plane stresses. The coupled system of equations for momentum and energy conservation are numerically solved. We show the results of the evolution of stress and deformation fields in the Alpine region. Geological interpretations support the lower resistance of the orogenic region between the stiff European foreland and the Adriatic lithosphere. Each plate is modeled in terms of a rheologically different block and the Alpine deformation changes dynamically according to the local rheology, the velocity field and the assumed coupling between Adria and Eurasia. We also analyze how the changes of the relative velocity between the Adriatic and European plates during the last 40 Ma affect the present-day structure Alpine chain. We show that Adria-Europe convergence and gravitational collapse alone are not able to induce the observed lateral extrusion in the eastern Alps. Our results suggest that other effects, such relative variations of strength in the different zones, the change of kinematics regime of Adria and Europe during the last 40 Ma and east-west extension due to the retreat of the Carpathians subduction zone, must be taken into account.
DE: 3230 Numerical solutions
DE: 8102 Continental contractional orogenic belts
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 8158 Plate motions--present and recent (3040)
DE: 8159 Rheology--crust and lithosphere
SC: Tectonophysics [T]
MN: 2003 Fall Meeting