کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6444640 1640490 2016 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Alteration-weakening leading to localized deformation in a damage aureole adjacent to a dormant shear zone
ترجمه فارسی عنوان
تضعیف تغییرات منجر به تغییر شکل موضعی در یک ناحیه آسیب دیده مجاور منطقه برشی خفته
کلمات کلیدی
آرچین، مناطق برشی، جریان سیالات، تغییر، شبکه های ضد انهدام زخم معده،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی
Deformation adjacent to faults and shear zones is traditionally thought to correlate with slip. Inherited structures may control damage geometry, localizing fluid flow and deformation in a damage aureole around structures, even after displacement has ceased. In this paper we document a post-shearing anastomosing foliation and fracture network that developed to one side of the Mesoarchean Marmion Shear Zone. This fracture network hosts the low-grade, disseminated Hammond Reef gold deposit. The shear zone juxtaposed a greenstone belt against tonalite gneiss and was locked by an intrusion that was emplaced during the final stages of suturing. After cessation of activity, fluids channeled along fault- and intrusion-related fractures led to the pervasive sericitization of feldspars. Foliated zones resulted from flattening in the weaker sericite-rich tonalite during progressive alteration without any change in the regional NW-SE shortening direction. The anastomosing pattern may have been inherited from an earlier ductile fabric, but sericite alteration and flattening fabrics all formed post-shearing. Thus, the apparent foliated fracture network adjacent to the Marmion Shear Zone is a second-order effect of shear-related damage, distinct in time from shear activity, adjacent to an effectively dormant shear zone. This phenomenon has implications for understanding the relative timing of fault zone activity, alteration and (in this case) gold mineralization related to long-term fault zone permeability.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Geology - Volume 90, September 2016, Pages 144-156
نویسندگان
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