کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4733233 1640537 2012 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Microstructures, crystallographic fabric development and deformation mechanisms in natural hematite aggregates deformed under varied metamorphic conditions
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Microstructures, crystallographic fabric development and deformation mechanisms in natural hematite aggregates deformed under varied metamorphic conditions
چکیده انگلیسی

Naturally deformed hematite aggregates from 15 different iron ore mines located in Quadrilátero Ferrífero region, Brazil, were analyzed in order to verify the influence of increasing temperature and deformation intensity on their microstructural and textural aspects as well as the deformation mechanisms associated with the metamorphic conditions. The electron backscattered diffraction (EBSD) technique was applied in order to get qualitative and quantitative data concerning with microstructural parameters, crystallographic preferred orientation (CPO) and misorientation between hematite grains. The microstructures of these aggregates vary from randomly oriented hematite grains with approximately equant grains, to strongly oriented and elongated grains following the increase in deformational and metamorphic polarity toward east in the region. In the low deformation domain (western region) the deformation mechanisms are typically microfracturing and dissolution precipitation creep for magnetite rich aggregates. In the high-strain domain (eastern region), the deformation is accommodated by a combination of basal intracrystalline slip (c) () and grain boundary sliding, with rotation around hematite [c] axis. No evidences for recrystallization processes in these aggregates can be supported by our results, probably due to the superposition of subsequent processes.


► We study iron formation rocks from Quadrilátero Ferrífero region, Brazil.
► They were deformed under varied metamorphic conditions.
► We use the EBSD for the microstructural and textural characterization.
► Microstructures, texture and deformation mechanisms in hematite vary in the area.
► Variations are due contrasting deformation/metamorphic conditions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 40, July 2012, Pages 29–43
نویسندگان
, ,