期刊
JOURNAL OF STRUCTURAL GEOLOGY
卷 55, 期 -, 页码 79-100出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jsg.2013.08.001
关键词
Anatexites; Anisotropy of magnetic susceptibility; Crystallographic preferred orientation; Magmatic flow; Aracuai belt
资金
- Fundacao de Amparo Pesquisa do Estado de Sao Paulo (FAPESP, Brazil) [2010/03537-7]
- Coordenacao de Aperfeicoamento Pessoal de Nivel Superior (CAPES, Brazil) [419011-4]
- FAPESP [2010/50475-1]
- Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [10/03537-7] Funding Source: FAPESP
The easternmost part of the Neoproterozoic Aracuai 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. (C) 2013 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据