گسلش و مورفوتكتونيك در زون بخاردن-قوچان

Faulting and morphotectonic in the Bakharden-Quchan zone

زون گسل بخاردن-قوچان در فاصله 150 كيلومتري شمال شرق مشهد از برجسته ترين چهره هاي توپوگرافي-ساختماني مركز كپه داغ در بين شهرهاي قوچان، شيروان و بجنورد است. مجموع گسل هاي امتداد لغز-راستگرد قوچان، باغان-گرماب، شيروان و غلامان-سومبار با روند شمالغرب-جنوبشرق از مهم ترين گسل هاي اين زون بوده كه فعاليت نوزمين ساختي آنها در نهشته هاي كواترنري قابل رديابي است. انتهاي اين گسل ها به صورت رورانده است. طبق شواهد دورسنجي و ميداني اين جنبش ها مي توان در ايجاد پديده هاي مورفوتكتونيكي مانند برخاستگي و برش پادگان هاي رودخانه اي، جابجايي ابراهه ها و تقطيع، برش و جابجايي رسوبات كواترنري مخروط افكنه اي مشاهده نمود. تراكم بالاي پراكنده اي زمين لرزه ها در پايانه گسل هاي قوچان و باغان و گرماب مي باشد.

1-Introduction In this paper fundamental goal is discussed about tectonic activities and survey role of different factors of forming and deformations to understand better about origin of morphotectonic of land forms occurring to reveal geomorphological patterns in the Bakharden-Quchan zone in the context of Arabia-Eurasia collision (Berberian, 1976; Lybris and Manby, 1999; Shabanian, 2009). 2-Methodology This paper uses of satellite images observations from Landsat 7, topographic data (SRTM), GIS and GPS data, geology and topographic maps, field observations of the morphotectonic landforms to clarify the active tectonics in the Bakharden-Quchan zone. 3-Results and discussion In this zone there is an array active right lateral-strike slip fault that they obliquely have cut the range and produced offsets of several Kms in the geological structures. These faults have identifiable ends, where they turn into thrust and link to blind faults mechanism changing of faults to revers have caused shortening by thrusting in their ends bending. Through convergence of Arabia-Eurasia plates have put constantly under neotectonic activities this zone since last phase of Alpine orogeny. Morphotectonic features have revealed by uplifts, deformations, ruptures and incision of late Quaternary traces, displacement of channel this sections, shear and displacement of Quaternary alluvial fan deposits. There faults have rotated anti clockwise around their vertical axes to cause several Kms of NS shortening. They also require of several Kms along strike extension that is taken by the westward component of motion between south Caspian Sea basin, Shahrood Fault system and both Eurasia and central Iran (Hollingsworth, 2006: Bretis and Conrady, 2012). 4-Conclusion The most important results of this paper is the identification of an array of active right lateral-strike slip faults which are almost certainly responsible for major destructive earthquakes in both historical and modern. All of these faults have ended where they turn into thrusts and link to blind faults. Mechanism changing of these faults to reverse of caused to increase stress, shortening by thrusting in their ends bending and their neotectonic activities create different morphotectonic features in Bakharden-Quchan zone particulary along the Qhuchan and Baghan-Garmab faults that there are enough morphotectonic evidences (Tchalenko, 1975; Masson et al., 2007; Shabanian, 2009).