کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6444780 1640508 2015 57 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The influence of phase and grain size distribution on the dynamics of strain localization in polymineralic rocks
ترجمه فارسی عنوان
تاثیر توزیع اندازه فاز و دانه بر دینامیک بودن محل تنش در سنگ های پلی مینرالیک
کلمات کلیدی
محلی سازی فشار، تسکین واکنش خزش نفوذ، پوسته میانی، فلدسپات، الکترون پراکندگی پراکنده،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی
Deformation microstructures of a quartzo-feldspathic pegmatite deformed at mid-crustal levels allow the study of the dynamics of strain localization in polymineralic rocks. Strain localization results from (i) difference in grain sizes between phases, both original and obtained during fluid present reactions and (ii) initial compositional banding. Due to original difference in grain size stress concentrates in the initially finer-grained phases resulting in their intense grain size reduction via subgrain rotation recrystallization (SGR). When the grain size is sufficiently reduced through either deformation or interphase coupled dissolution-precipitation replacement of the coarse grained feldspar, aggregates start to deform by dominantly diffusion accommodated grain boundary sliding (GBS). Phase mixing inhibits grain growth and sustains a grain size allowing GBS. Consequently, discontinuous microscale shear zones form locally within initially coarse grained areas. At the same time difference in strain rate between feldspar-rich and quartz-rich domains needs to be accommodated at domain boundaries. This results in the formation of continuous mesoscale shear zones deformed by GBS. Once these are formed, deformation in the coarse grained parts is arrested and strain is mainly accommodated in the mesoscale shear zones resulting in “superplastic” behaviour consistent with diffusion creep.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 72, March 2015, Pages 15-32
نویسندگان
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