M Rostamiyan; M Khademi; S.S Eslami; H Shahbazi
Abstract
In the western part of Miami fault zone (MFZ) as a partial boundary of two main structural zones (Centeral Iran and Binaloud) in the Iranian plateau, since the fault is covered by alluviums or displaced rocks, poor and limited field data cannot solve the problems concerning deformation history and evolutionary ...
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In the western part of Miami fault zone (MFZ) as a partial boundary of two main structural zones (Centeral Iran and Binaloud) in the Iranian plateau, since the fault is covered by alluviums or displaced rocks, poor and limited field data cannot solve the problems concerning deformation history and evolutionary path of the MFZ. To facilitate unraveling the structural problem, we tried to conduct five experimental models using a combination of compressional, dextral and sinistral mechanisms with changes in the geometry of two main boundary faults. Based on the results, evidences from transpression with dominant dextral component are very similar to field observations along the western MFZ, including folds, Riedel shears, duplexes, fault geometry and bends. Based on the model, deformation in the western part of MFZ is accommodated by dextral non-coaxial shear with compressional component. The experimental model provided a proper insight about deformation history and style. It is proposed that the western part of the MFZ has been deformed by dextral non-coaxial shear with compressional component, and some resultant rotations have probably changed structural trends during time.
M Ramazani; M. R. Ghassemi; A Zanchi; M. R Sheikholeslami
Abstract
Theerosional window of Aghdarband , located in NE Iran to the SE of Mashhad is a unique place for study of the Eo-Cimmerian event. This event (Late Triassic-Middle Jurassic) resulted from clousureof thePaleothetys ocean and collision between the Iran and Turan plates. These two plates were separated ...
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Theerosional window of Aghdarband , located in NE Iran to the SE of Mashhad is a unique place for study of the Eo-Cimmerian event. This event (Late Triassic-Middle Jurassic) resulted from clousureof thePaleothetys ocean and collision between the Iran and Turan plates. These two plates were separated from each other before Late Triassic, and therefore they had different tectonic and sedimentary histories. At this time the Aghdarband area was located on active margin of Eurasia, and therefore the units that are exposed in the erosional wiondow of Aghdarband have basic differences with their counterparts in other places of Iran. During the Eo-Cimmerian event, the Aghdarband area was affected by a sinistraltranspression. Strain in this transpressional zone was intensively partitioned, and three major structural domains with different structural characteristics were formed in it. A sinistral strike-slip fault zone and an imbricate thrust fault zone were formed respectively in northern and southern part of the Aghdarband area. Development of this transpressional zone may be attributed to the oblique convergence between Iran and Turan plates during above mentioned time interval.
Z. Malekzadeh; M. R. Abbassi; O. Bellier; C. Authemayou; I. Shabanian
Abstract
The present study covers the area between 500E to 510, 30`E of the Zagros Fold-and-Thrust Belt. The deformation pattern of west High Zagros Belt (HZB) has been considered to reflect a complete strain partitioning due to the Arabian oblique plate convergence and Central ...
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The present study covers the area between 500E to 510, 30`E of the Zagros Fold-and-Thrust Belt. The deformation pattern of west High Zagros Belt (HZB) has been considered to reflect a complete strain partitioning due to the Arabian oblique plate convergence and Central Iran. In this context the NW-SE trending Main Recent Fault (MRF) acts as rear boundary of the belt, kinematically taking up the strike-parallel component of oblique plate motion of Arabia, whereas the High Zagros Fault (HZF) with the same fault trend as MRF accommodates the orogen-normal shortening due to this movement. Using fault-slip inversion on fault planes mostly affecting the Bakhtiary conglomerate (Plio-Pleistocene in age) along the HZB, the deviatoric stress tensor and its shape factor (R) calculated at 29 stations. The geomorphic evidences and the fault kinematics show that the major parts of the HZF are consistent with strike-slip kinematics. This implies that the HZF also accommodates some part of strike-parallel component of oblique convergence collision.
