کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9527058 | 1636983 | 2005 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Possible orogeny-parallel lower crustal flow and thickening in the Central Andes
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
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 1019 Pa s, this flow reaches 1 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.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volume 399, Issues 1â4, 27 April 2005, Pages 59-72
Journal: Tectonophysics - Volume 399, Issues 1â4, 27 April 2005, Pages 59-72
نویسندگان
M. Gerbault, J. Martinod, G. Hérail,