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محمد سیاری مرتضی شریفی

چکیده

در منطقه قهرود (شمال اصفهان)، سنگهای آتشفشانی با ترکیب آندزیت تا بازالت به‌صورت توده‌هایی با ابعاد مختلف پراکنده‌اند. از نظر کانی‌شناسی، سنگهای آتشفشانی بازالتی مورد بررسی از فنوکریست‌های پلاژیوکلاز به‌همراه بلورهای کوچکتر کلینوپیروکسن در زمینه‌ای از میکرولیت، شیشه و کانیهای کدر تشکیل شده‌اند. پلاژیوکلازها ترکیب لابرادوریت- بیتونیت (41-An85-58Ab15) دارند و کلینوپیروکسنها از نوع اوژیت (26-En41-49Di29-38Fs17) هستند. ترکیب کلینوپیروکسن‌ها نشان می‌دهد، ماگمای مادر سنگها دارای ماهیت تولئیتی است. بر اساس محاسبات نظام‌‌مند زمین‌دما- فشارسنجی با استفاده از نرم‌افزار تخصصی SCG، کلینوپیروکسنها در محدوده دمایی حدود 1120-1170 درجه سانتیگراد و محدوده فشار حدود 2-6 کیلوبار متبلور شده‌‌اند. پردازشهای آماری نشان می‌دهد، همگام با صعود ماگما و تبلور هم‌زمان پیروکسن‌‌ها، در قبال هر درجه سانتی‌گراد کاهش دما، به میزان 6/84 بار از فشار وارد بر ماگما کاسته شده که معادل با 320 متر کاهش عمق در پوسته قاره‌ای است.

جزئیات مقاله

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ارجاع به مقاله
سیاریم., & شریفیم. (۱۳۹۵-۰۴-۰۵). استفاده از ترکیب شیمیایی کلینوپیروکسن در تحلیل شرایط فیزیکی صعود ماگما، بررسی موردی سنگهای آتشفشانی ائوسن در منطقه قهرود (شمال اصفهان). زمین‌شناسی اقتصادی, 8(1), 61-78. https://doi.org/10.22067/econg.v8i1.38857
نوع مقاله
علمی- پژوهشی