The nature and movement of thrusts in the eastern Iranian orogen:Sechengi Area on the northern border of Lut and Sistan  

作　　者：Shahriar KESHTGAR Mahmoud Reza HEYHAT Sasan BAGHERI Ebrahim GHOLAMI Seyed Naser RAISOSSADAT 

机构地区：[1]Department of Geology,Faculty of Science,University of Birjand,Birjand 9717434765,Iran [2]Department of Geology,Faculty of Science,University of Sistan and Baluchestan,Zahedan 98167-45845,Iran

出　　处：《Journal of Mountain Science》2024年第9期3157-3171,共15页山地科学学报（英文）

基　　金：financially and technically supported by the University of Birjand under Project Number 7912.

摘　　要：The eastern Iranian range,known as the Sistan suture zone in the past,has recently been identified as the Sistan orogen.This Paleogene orogeny is located between the Lut and Afghan microcontinents.The structural analysis shows that most of the thrusts dip towards the NW so that the Permo-Triassic sediments and Jurassic micro-diorites of the Lut Block overthrusted over the younger rocks.Structural studies show that the tectonic vergence was from the NW to the SE of the Sechengi area in the NW part of Sistan orogen.We recognized three deformation phases in eastern Iran.The first N-S deformation event(D1)resulted in the formation of tight E-W folds(F1)and associated cleavages(S1).The second E-W deformation event(D2),which occurred in the late Paleogene led to the bending of older structures,including the axial plane of the first-generation folds giving them a new northwest direction(F2).Additionally,the ramp of the first-phase thrusts(striking E-W)was reactivated,acquiring a new NNW orientation and exhibiting SSE tectonic vergence.The third deformation event(D3)resulted in the formation of NNE and WNW conjugate faults in eastern Iran.Such consecutive deformation events perpendicular to each other are inconsistent with the models of simple linear orogen presented for eastern Iran(i.e.rifting of eastern Iran continental crust and subsequence linear collision)and seem more consistent with the buckling orogeny(Orocline).

关 键 词：Thrust Tectonic vergence Orocline Buckling Sechengi Eastern Iranian ranges. 

分 类 号：P542[天文地球—构造地质学]