کانی شناختی, دگرگونی و زمین دما فشار سنجی مجموعه دگرگونی منطقه قنداب واقع در جنوب شرق فریمان (شمال شرق ایران)

نویسندگان

دانشگاه فردوسی مشهد

چکیده

منطقه مورد مطالعه در 110 کیلومتری شمال شرق مشهد و 40 کیلومتری جنوب شرق فریمان قرار گرفته است. این منطقه بخشی از زون ایران مرکزی به شمار می رود و در بر گیرنده سنگهای دگرگونی می باشد که سنگ اولیه آنها شامل ترکیبات پلیتی , کربناتی  و کوارتز فلدسپاتی است. دگرگونی در منطقه مورد مطالعه از نوع مجاورتی در مقیاس ناحیه ای فشار پایین – حرارت بالا پیشنهاد شده است.  بر اساس مطالعات سنگ شناختی در منطقه مورد مطالعه دگرگونی در حد بخش فوقانی رخساره آمفیبولیت می باشد.  بر اساس سه مجموعه کانی شناختی , سه زون در این منطقه شامل زون های آندالوزیت- کردیریت, آندالوزیت- سیلیمانیت و سیلیمانیت – پتاسیم فدسپار تشخیص داده شده است.  میزان حداکثر دما و فشار دگرگونی با استفاده از نرم افزار ترموکالک به طور میانگین 664 درجه سانتیگراد و 5/2 کیلوبار فشار محاسبه شده است. بر اساس حداکثر فشار محاسبه شده (5/2 کیلوبار ) عمق 8/7 کیلومتربرای دگرگونی تخمین زده می­شود. 

کلیدواژه‌ها


عنوان مقاله [English]

Mineralogy, metamorphism and geothermobarometry of the Ghandab metamorphic Complex, SE Fariman, NE Iran

چکیده [English]

The study area is located about 110 kilometers southeast of Mashhad and approximately 40 kilometers southeast of Fariman. The area is considered to be a part of the central Iran zone. It includes metamorphic rocks with different protoliths consisting of pelitic, carbonate and quartz - feldspathic rocks. The metamorphism in the study area is considered to be a contact regional metamorphism with a low pressure - high temperature grade. According to petrographic studies, the metamorphism in the region reached the upper limit of amphibolite facies.  On the basis of different mineral assemblages, three zones were recognized, including Andalusite-Cordierite, Sillimanite - Andalusite, and Sillimanite – K-Feldspar zones. Using Thermocalc software, the average temperature and pressure for the peak of metamorphism in the metapelitic rocks are 664 ºC and 2.5 Kbar respectively. Based on calculated maximum pressure (2.5 Kbar), the depth of ~7.8 Km for the metamorphism is estimated.

کلیدواژه‌ها [English]

  • amphibolite facies
  • contact regional metamorphism
  • Fariman
  • low P-high T
  • Thermocalc
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