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Gerbault Muriel, Martinod Joseph, Hérail Gérard. (2005). Possible orogeny-parallel lower crustal flow and thickening in the Central Andes. Tectonophysics, 399 (1-4) Special Iss. SI, p. 59-72. ISSN 0040-1951.

Titre du document
Possible orogeny-parallel lower crustal flow and thickening in the Central Andes
Année de publication
2005
Type de document
Article référencé dans le Web of Science WOS:000228848500004
Auteurs
Gerbault Muriel, Martinod Joseph, Hérail Gérard
Source
Tectonophysics, 2005, 399 (1-4) Special Iss. SI, p. 59-72 ISSN 0040-1951
The relatively low elevation and thick crust in the Altiplano, in comparison to the higher elevation, but thinner crust in the Puna plateau, together with geophysical data, suggests that isostatic equillibrium is achieved by cooler and denser lithospheric mantle in the Altiplano. Excess density in the Altiplano mantle could create differential horizontal stress in the order of 25 MPa between both lithospheric columns. Numerical models accounting for pressure and temperature-dependent rheology show that such stress can induce horizontal ductile flow in the lower crust, from the Puna towards the Altiplano. With a minimum viscosity of 10(19) Pa s, this flow reaches I cm/year, displacing more than 50 km of material within 5 Ma. If the lower crust viscosity is smaller, the amount of orogeny-parallel lower crustal flow can be even greater. Such a mechanism of channel flow may explain that different amounts of crustal material have been accommodated by shortening in the Altiplano and in the Puna. Because of the strength of the elastic-brittle upper crust, this channel flow does not necessitate large amounts of surface deformation (except vertical uplift), making it difficult to detect from the geology. © 2005 Published by Elsevier B.V.
Plan de classement
Géologie et formations superficielles [064]
Description Géographique
ANDES
Localisation
Fonds IRD [F B010042318] ; Quito
Identifiant IRD
fdi:010042318
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