The onset of extension during lithospheric shortening: a 2-D thermo-mechanic model for lithospheric unrooting
Articolo
Data di Pubblicazione:
1999
Citazione:
The onset of extension during lithospheric shortening: a 2-D thermo-mechanic model for lithospheric unrooting / A.M. Marotta, M. Fernandez, R. Sabadini. - In: GEOPHYSICAL JOURNAL INTERNATIONAL. - ISSN 0956-540X. - 139:1(1999), pp. 98-114.
Abstract:
We model the evolution of the lithosphere during its shortening and consequent gravitational collapse with special emphasis on the induced variations in the surface stress regime and dynamic topography. In particular, we analyse the conditions leading, immediately after lithospheric failure, to local extension, eventually coeval with compression. Different crustal rheologies and kinematic conditions as well as thermally imposed mechanical rupture are considered. Numerical calculations have been performed by using a 2-D finite element code that couples the thermal and mechanical equations for a Newtonian rheology with a temperature-dependent viscosity. The results show that, after the failure of a gravitationally unstable lithospheric root, the replacement of lithospheric mantle by warmer asthenospheric material induces a considerable variation in the dynamic topography and in the surface stress regime. The occurrence of local extension, its intensity and its spatial distribution depend mainly on whether convergence continues throughout the process or ceases after or before the lithospheric failure. Similarly, uplift/subsidence and topographic inversion are controlled by kinematic conditions and crustal rheology. Mechanical rupture produces drastic changes in the surface stress regime and dynamic topography but only for a short time period, after which the system tends to evolve like a continuous model.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Extension; Gravitational collapse; Lithospheric shortening; Topographic instability
Elenco autori:
A.M. Marotta, M. Fernandez, R. Sabadini
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