بررسي هندسه آبخوان دشت صحنه - ‌بيستون برپايه پژوهش‌هاي ريخت‌ زمين‌ ساختي و گسلش جنبا، استان كرمانشاه، ايران

Aquifer geometry of Sahneh-Bisetun plain based onmorphotectonic and active faulting, Kermanshah province, Iran

دشت صحنه - بيستون با روند عمومي شمال باختري - جنوب خاوري، در شمال خاوري استان كرمانشاه جاي دارد و كم‌وبيش با روند اصلي پهنه ساختاري زاگرس هم‌راستاست. همجواري اين گستره با گسل اصلي جوان زاگرس (Main Recent Fault) اهميت مطالعه آن را افزايش مي‌دهد. در اين پژوهش، ضمن بازخواني و شناساندن گسل‌هاي تأثيرگذار در دشت صحنه-بيستون، چگونگي شكل‌گيري ساختار دشت با توجه به عملكرد گسل‌هاي جنباي پيراموني بررسي شده ‌است. نتايج كلي نشان مي‌دهد كه ريخت‌شناسي اين دشت، بر آمده از كاركرد دو گسل نهان و جنباي بدربان (Badrban) و برناج (Barnaj) بوده است؛ بدين گونه كه به سبب حركت عادي گسل برناج در خاور كوهستان بيستون- تاق بستان و سازوكار راندگي گسل بدربان، حوضه صحنه- بيستون تشكيل شده است. الگوي ساختاري آبخوان دشت هرسين- بيستون، با توجه به آهنگ و هم‌سنجي ساختار گسل‌هاي جنباي پيراموني به عنوان گسل‌هاي كنترل‌ كننده حوضه كواترنري با استفاده از داده‌هاي كمي ژئوالكتريكي و تحليل كيفي رفتار آبخوان تعيين شد. ستبراي آبخوان دشت، در بخش‌هاي گوناگون آن مشخص شد؛ به گونه‌اي كه ستبرترين بخش آبرفت آبخوان در بخش مركزي دشت قرار دارد و به سوي شمال باختري يا جنوب خاوري و با نزديك شدن به واحدهاي سنگي پيراموني، از ستبراي آن كاسته مي‌شود.

The NW-SE trendingSahneh-Bisetun Plain is located in the northeast of the Kermanshah province, and is extendedmore or less sub-parallel with the Zagros structural zone. The proximity of this plain with the Main Recent Fault (MRF) makes its study more important. In this study, in addition to the identification of the faults affecting the Sahneh-Bisetun Plain, formation of the plain and how it evolved in association with the active surrounding faults have been investigated. The general results of this study show that the geometry and morphology of this plain is affected by the Badrban and Barnaj active and hidden faults. The Sahneh-Bistun basin has been formed as the result of normal movement of the Barnaj fault in east of the Bistun-Tagh Bostan Mountain and thrust mechanism of the Badrban fault. The structural pattern of the aquifer was determined by the study of the interaction of active surrounding faults controlling the Quaternary basin and by using geo-electric data and qualitative analysis. Thickness ofaquifer in different parts of the plain was also measured. It indicates that the thickest part of the alluvium is located at the center of the plain and thins towards the surrounding rock units in the northwest or southeast. The NW-SE trendingSahneh-Bisetun Plain is located in the northeast of the Kermanshah province, and is extendedmore or less sub-parallel with the Zagros structural zone. The proximity of this plain with the Main Recent Fault (MRF) makes its study more important. In this study, in addition to the identification of the faults affecting the Sahneh-Bisetun Plain, formation of the plain and how it evolved in association with the active surrounding faults have been investigated. The general results of this study show that the geometry and morphology of this plain is affected by the Badrban and Barnaj active and hidden faults. The Sahneh-Bistun basin has been formed as the result of normal movement of the Barnaj fault in east of the Bistun-Tagh Bostan Mountain and thrust mechanism of the Badrban fault. The structural pattern of the aquifer was determined by the study of the interaction of active surrounding faults controlling the Quaternary basin and by using geo-electric data and qualitative analysis. Thickness ofaquifer in different parts of the plain was also measured. It indicates that the thickest part of the alluvium is located at the center of the plain and thins towards the surrounding rock units in the northwest or southeast.