بررسی شیمی‌کانی و چگونگی تشکیل تورمالین‌ در بیوتیت‌آمفیبولیت‌های مجموعه دگرگونی گل‌گهر سیرجان-کرمان

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه زمین‌شناسی، دانشگاه شهید باهنر کرمان، کرمان، ایران

چکیده

مجموعه دگرگونی گل­گهردر لبه جنوب‏شرقی پهنه دگرگونی سنندج- سیرجان و در شهرستان سیرجان، استان کرمان، واقع شده است. سنگ­های تشکیل دهنده این مجموعه شامل انواع شیست­ها، آمفیبولیت­ها و سنگ­های متابازیت هستند. از اجزای اصلی سنگ­شناسی منطقه بیوتیت آمفیبولیت­ها با مشخصه کانی­شناسی هورنبلند، پلاژیوکلاز، بیوتیت، تورمالین، اسفن، اپیدوت، سریسیت، کلریت، کلسیت و کانی­های کدر هستند که در این پژوهش تشکیل تورمالین در بیوتیت آمفیبولیت­های منطقه بررسی شده است.  تجزیه کانی­های تورمالین موجود در بیوتیت آمفیبولیت منطقه مورد بررسی به روش ریزپردازش الکترونی نشان داد که این تورمالین­ها مقدار منیزیم بالا داشته و در گستره دراویت و گروه قلیایی قرار دارند. ارتباط مثبت میان مقادیر Mg و Fe، بالا بودن مقدار کاتیون Mg در تورمالین­ها، ارتباط منفی میان Al و Fe/(Fe+Mg) و روند منفی Ca نسبت به Na که نشان­ از رخ دادن جانشینی
AlNa-1Mg-1 در تورمالین­های مورد بررسی دارد، مشخصه غیر ماگمایی و دگرگونی بودن این تورمالین­ها هستند. تشکیل این کانی را می­توان به حضور مقدار بالای کانی بیوتیت در سنگ مورد بررسی و سیال سرشار از بور که طی دگرگونی در سیال­های میان روزنه­ای انباشته شده است نسبت داد. سیال سرشار از بور با کانی بیوتیت واکنش داده و موجب بوجود آمدن تورمالین­ها شده است.      

کلیدواژه‌ها


عنوان مقاله [English]

Investigation of mineral chemistry and causes of tourmaline formation in biotite amphibolits of Gol-e-Gohar mining and industrial area (Sirjan), Kerman province

نویسندگان [English]

  • Ghafouri
  • Moein Zadeh
چکیده [English]

The Gol-e-Gohar metamorphic complex is located in the southeast of Sanandaj-Sirjan Zone, in Sirjan city (Kerman Province). According to EPMA data of the tourmaline in the biotite-amphibolite of the studied area, these tourmalines are high Mg tourmalines and dravite ones and belong to the alkaline series. The positive correlation between Mg and Fe contents, high contents of Mg in the studied tourmalines, as well as the negative correlation between Al and Fe/(Fe+Mg) and Ca vs. Na, are all indicative of the substitution of []AlNa-1Mg-1, which indicating that these minerals are not magmatic tourmalines, instead metamorphic minerals. It appears that the reason for the formation of this mineral can be related to the high presence of biotite in the studied rocks and boron-rich fluids that concentrated in interstitial fluids. The boron-rich fluids reacted with biotite and formed the studied tourmalines.

کلیدواژه‌ها [English]

  • Gol-e-Gohar metamorphism complex
  • Sanandaj-Sirjan Zone
  • tourmaline
  • biotite amphibolite
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