کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4733174 | 1640522 | 2013 | 22 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Strain distribution across a partially molten middle crust: Insights from the AMS mapping of the Carlos Chagas Anatexite, Araçuaà belt (East Brazil)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
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چکیده انگلیسی
The easternmost part of the Neoproterozoic Araçuaà belt comprises an anatectic domain that involves anatexites (the Carlos Chagas unit), leucogranites and migmatitic granulites that display a well-developed fabric. Microstructural observations support that the deformation occurred in the magmatic to submagmatic state. Structural mapping integrating field and anisotropy of magnetic susceptibility (AMS) revealed a complex, 3D structure. The northern domain displays gently dipping foliations bearing a NW-trending lineation, southward, the lineation trend progressively rotates to EW then SW and the foliation is gently folded. The eastern domain displays E-W and NE-SW trending foliations with moderate to steeply dips bearing a dominantly NS trending lineation. Magnetic mineralogy investigation suggests biotite as the main carrier of the magnetic susceptibility in the anatexites and ferromagnetic minerals in the granulites. Crystallographic preferred orientation (CPO) measurements using the electron backscatter diffraction (EBSD) technique suggest that the magnetic fabric comes from the crystalline anisotropy of biotite and feldspar grains, especially. The delineation of several structural domains with contrasted flow fabric suggests a 3D flow field involving westward thrusting orthogonal to the belt, northwestward orogen-oblique escape tectonics and NS orogen-parallel flow. This complex deformation pattern may be due to interplay of collision-driven and gravity-driven deformations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 55, October 2013, Pages 79-100
Journal: Journal of Structural Geology - Volume 55, October 2013, Pages 79-100
نویسندگان
Geane C.G. Cavalcante, Marcos Egydio-Silva, Alain Vauchez, Pierre Camps, EurÃdice Oliveira,