بررسی پارامترهای هندسی و کینماتیکی تاقدیس سرکان، لرستان، غرب ایران
محورهای موضوعی :رضا علی پور 1 , امیرحسین صدر 2 * , سمیرا شه‌مرادی 3 , عارف شمس‌زاده 4
1 - گروه زمین‌شناسی، دانشکده علوم‌زمین، دانشگاه شهید بهشتی
2 - دانشگاه بوعلی‌سینا همدان
3 - دانشگاه بوعلی‌سینا همدان
4 - دانشگاه شیراز
کلید واژه: پارامتر هندسی, تاقدیس, سرکان, زاگرس, لرستان.,
چکیده مقاله :
تاقدیس سرکان در پهنه رسوبی - ساختاری لرستان و در کمربند چین‌خورده رانده زاگرس قرار می‌گیرد. هندسه و کینماتیک چین‌ها در این پهنه توسط گسل‌های راندگی و سطوح جدایشی کنترل می‌شود. سازندهای رخنمون یافته در این تاقدیس، سازندهای کرتاسه بالایی و سنوزوئیک هستند. در این پژوهش، با استفاده از تفسیر نیمرخ‌های لرزه‌ای و رسم چهار نیمرخ ساختاری و محاسبه پارامترهای هندسی، به بررسی هندسه و تحلیل سبک دگرریختی تاقدیس و نقش سطوح جدایشی بر سبک چین‌خوردگی آن پرداخته شده است. ساختار این تاقدیس تحت‌تاثیر دو سطح جدایش قرار می‌گیرد که سازند فلیشی امیران به‌عنوان سطح جدایش بالایی و سازند شیلی گرو نیز به‌عنوان سطح جدایش میانی است. ضخامت زیاد سطح جدایش بالایی باعث جابجایی به سمت جنوب‌غرب محور تاقدیس سطحی نسبت به تاقدیس عمقی شده است. بررسی‌های انجام شده بر روی پارامترهای هندسی و نیمرخ‌های ساختاری تاقدیس سرکان نشان‌دهنده نامتقارن و استوانه‌ای بودن این تاقدیس است و از لحاظ فشردگی و نسبت ابعادی به ترتیب در رده، باز تا ملایم و پهن قرار می‌گیرد.
The Sarkan anticline is located in the Lurestan sedimentary-structural zone and in the Zagros fold and thrust belt. Geometry and kinematic of the fold of this zone are controlled by thrust faults and detachment levels. The exposed formations in this anticline are the upper Cretaceous and Cenozoic formations. In this research, geometry and deformational style analysis of the anticline and role of the detachment levels on folding style have been investigated using drawing four structural cross-sections, interpretation of the seismic profiles and calculation of geometric parameters. The structure of this anticline is affected by two detachment horizon, which is the flysch Amiran, and shaly Garu formations as the upper and middle detachment levels, respectively. The high thickness of the upper detachment level caused displacement of the surface anticline axis to the SW with respect to the deep anticline axis. The study of geometrical parameters and structural cross-sections of the Sarkan anticline exhibit that this structure is an asymmetric and noncylindrical anticline, and from tightness and aspect ratio view is ranked in the open to gentle and wide category, respectively.
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