دگرشکلی های ساختاری گستره معدن دونا

نوع مقاله: مقاله پژوهشی

نویسنده

دانشگاه آزاد اسلامی واحد لاهیجان

چکیده

چکیده
محدوده معدن دونا قسمتی از پهنه زمین‌شناسی البرزمرکزی است. تاقدیس دونا قسمتی از یک ساختار فراجسته تکتونیکی است که در حدفاصل گسل‌‌های رانده کندوان و آزادکوه جای گرفته است. در این تحقیق سه گروه از گسل‌‌های اصلی شناسایی شده‌اند. گروه اول این گسل‌‌ها هم‌راستای محور چین‌های مهم و دارای راستای خاوری- باختری و شیب حدود 50-40 درجه و زاویه ریک بیش از 70 درجه هستند. گروه دوم گسل‌ها دارای امتدادNE-SW با سازوکار معکوس و زاویه ریک کمتر از 65 درجه می‌باشند. گروه سوم گسل‌‌ها که اولین گروه گسل‌ها را قطع می‌کنند، دارای راستای تقریبی N35W ، شیب بیش از 75 درجه و زاویه ریک بیش از 70 درجه هستند. هدف از این نوشتار بررسی ساختار معدن دونا و بررسی سازو کار سومین گروه گسل‌ها می‌باشد که در البرز عمومیت ندارند و تجزیه و تحلیلی در مورد آن‌ها ارائه نشده است. برخی از این گسل‌‌ها خش‌لغزهای بارزی نداشتند و سازوکار این گسل‌‌ها با استفاده از تهیه نقشه زمین‌شناسی 1:1000، تهیه برش‌های ساختاری و به کارگیری شبکه اشمیت و روش‌های ترسیمی به دست آمد. تغییر نوع حرکات تکتونیکی از نوع تکتونیک برخوردی به حرکات راستالغز چپ‌بر در ساختار فراجسته دونا سبب ایجاد گسل‌های معکوس جوان با راستای شمال باختری- جنوب‌خاوری شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Structural deformations of Dona mine

نویسنده [English]

  • Saeid Hakimi Asiabar
استادیار
چکیده [English]

Abstract
The area of Dona mine is a part of central Alborz. The Dona anticline is a part of pop up structure and located between Kandavan and Azadkuh thrust faults. In this research three sets of major faults are recognized. The first category of faults with W-E trend, dip 40-50, Rake angle more than 70, are parallel to the major fold axes and second category of faults have NE-SW trend with reverse movement and rake angle less than 65. The third category which truncate the first sets, have nearly N30W to N40W direction with dip more than 75 and rake angle more than 70. The aim of this paper is investigation on the structure of Dona mine and investigations on the mechanism of third category of faults which are not popular in Alborz range and did not discussed before. Some of these faults do not have visible slickensides and the mechanism of these faults held on the basis of preparing geologic map on the scale of 1:1000, structural cross sections and implementing Schmidt net with construction methods. The change of tectonic movements from collision into sinstral, on the pop-up structure created this set of young reverse faults with NW-SE trend.

کلیدواژه‌ها [English]

  • Dona lead mine
  • mechanisms of faults
  • Kandavan fault
  • Alborz
  • Iran

سامانی­راد، ش.، 1379- زمین­شناسى، ‌سنگ‌شناسى و تعیین ژنز معدن سرب دونا در البرز مرکزى، پایان‎نامه کارشناسى ارشد دانشگاه آزاد اسلامى، واحد تهران شمال.

صباحى، ف.، 1384- نحوه تشکیل کانسار دونا و اثرات زیست‌محیطی معدنکاری آن بر رودخانه­های الیکا، دونا و چالوس، پایان‎نامه کارشناسی ارشد، پژوهشکده علوم زمین.

 

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