Investigation of deformation fabrics and emplacement mechanism of NW- Zahedan granites (Kuhe-Zargoli)

Geotechnical Geology

دوره 3، شماره 2، مرداد 2007، صفحه 129-143   

نوع مقاله: Original Research

نویسندگان

Shahriar Keshtgar^* ؛ Mahbobe Nazari

Department of Geology, Faculty of Science, Islamic Azad University - Zahedan Branch, Zahedan, Iran

چکیده

The NE-SW trending Zargoli intrusion, which is located in the Zahedan-Saravan Granitoid belt, has intruded into the Sistan suture zone. Host rocks of this pluton are metamorphosed flysch-type sediments southeast of Iran. Plutonic rocks namely, granodiorite, monzogranite and biotite granite, are moderately to highly deform along with the occurrence of relatively extensive sinstral and dextral shear zones. The occurrence of features such as quartz ribbons, mechanical twining in plagioclases, biotite micafish and transformation of orthoclase minerals into microcline in these rocks along with the formation of S-C type mylonite and cataclasite, are all demonstrations of a dynamic metamorphic event in ductile to brittle conditions. Distribution and configuration of porphyroclasts in the mylonitic granite exhibit a Sinstral (Eastern part) and dextral (Western part) shear sense. According to microstructures, ductile deformation occurred between 300-450°c in moderate to high greenschist facies conditiones.

کلیدواژه‌ها

Granit؛ Deformation؛ Shear zone؛ Petrofabric؛ Emplacement؛ Zahedan