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dynamique et regime thermique des chaines de montagnes - application aux Andes Centrales

Abstract : Convergent zones show highly variable tectonical, morphological and thermal signatures. Some orogenic belts, like the Central Andes, locally undergo a neutral to extensive tectonic regime, while the whole belt is globally shortening. The balance between tectonic and buoyancy forces within the crust controls the dynamics of the margin. The physical parameters ruling the evolution of the margin can be deduced from topography; in the Andes, the involved stresses range between 25 MPa and 75 MPa, the total involved force is 5. 1012 N m-1, and the viscosity is in the order of 2.1021 Pa s. A time-marching model is developed for the lithosphere, on the basis of the thin viscous sheet approximation. Minor differences in the boundary conditions conveniently explain the evolution of both compressive and extensive active plate margins. The impact of a denser lithospheric root on the dynamics is also explored. The tectonic evolution of active margins disturbs their thermal fields. Highly variable thermal signatures within orogenic belts are evidenced. Heat sources include static sources, i.e. shear heating at the base of the lithosphere, magmatism, convective removal of the lithospheric root, erosion, sedimentation, etc. A theoretical approach is carried out in order to estimate the various thermal contributions and to assess their influences within different morphotectonic units. Particular attention is paid to surface processes. These investigations are applied to the Central Andes, where numerous thermal and additional geophysical information is available.
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Contributor : Laurent Husson <>
Submitted on : Friday, January 16, 2004 - 11:46:04 AM
Last modification on : Tuesday, February 18, 2020 - 3:42:01 PM
Long-term archiving on: : Friday, April 2, 2010 - 7:12:42 PM

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  • HAL Id : tel-00004191, version 1

Citation

Laurent Husson. dynamique et regime thermique des chaines de montagnes - application aux Andes Centrales. Géologie appliquée. Ecole normale supérieure de lyon - ENS LYON, 2001. Français. ⟨tel-00004191⟩

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