Numerical models of ductile rebound of crustal roots beneath mountain belts |
| |
Authors: | Hemin A Koyi A Geoffrey Milnes Harro Schmeling Christopher J Talbot Christopher Juhlin & Hermann Zeyen |
| |
Institution: | Hans Ramberg Tectonic Laboratory, Department of Earth Sciences, Villavägen 16, S-752 36 Uppsala, Sweden. E-mail:;, Department of Geology, University of Bergen, N-5007 Bergen, Norway;, Institut für Meteorologie und Geophysik, Universität Frankfurt, Feldbergstrasse 47, 60323 Frankfurt am Main, Germany;, Département des Sciences de la Terre Universitéde Paris-Sud, Bât. 504, F-91405 Orsay, cedex, France |
| |
Abstract: | Crustal roots formed beneath mountain belts are gravitationally unstable structures, which rebound when the lateral forces that created them cease or decrease significantly relative to gravity. Crustal roots do not rebound as a rigid body, but undergo intensive internal deformation during their rebound and cause intensive deformation within the ductile lower crust. 2-D numerical models are used to investigate the style and intensity of this deformation and the role that the viscosities of the upper crust and mantle lithosphere play in the process of root rebound. Numerical models of root rebound show three main features which may be of general application: first, with a low-viscosity lower crust, the rheology of the mantle lithosphere governs the rate of root rebound; second, the amount of dynamic uplift caused by root rebound depends strongly on the rheologies of both the upper crust and mantle lithosphere; and third, redistribution of the rebounding root mass causes pure and simple shear within the lower crust and produces subhorizontal planar fabrics which may give the lower crust its reflective character on many seismic images. |
| |
Keywords: | numerical models root rebound Western Gneiss complex |
|
|