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The recently developed fluorite (U–Th)/He thermochronology (FHe) technique was applied to date fluorite mineralization and elucidate the exhumation history of the Mazandaran Fluorspar Mining District (MFMD) located in the east Central Alborz Mountains, Iran. A total of 32 fluorite single-crystal samples from four Middle Triassic carbonate-hosted fluorite deposits were dated. The presented FHe ages range between c.?85?Ma (age of fluorite mineralization) and c.?20?Ma (erosional cooling during the exhumation of the Alborz Mountains). The Late Cretaceous FHe ages (i.e. 84.5???3.6, 78.8???4.4 and 72.3???3.5?Ma) are interpreted as the age of mineralization and confirm an epigenetic origin for ore mineralization in the MFMD, likely a result of p
The Main Recent Fault (MRF) is a major active strike-slip fault system at the NE border of the Arabian platform and Central Iran. Both geometry and kinematics of the fault system is rather well known along its central part and at its SE termination, while its possible continuation to the northwest is ambiguous. Moreover, less regard has been paid to possible relationships between this major intracontinental fault system and other strike-slip faults in NW Iran – SE Anatolia. This paper investigates both the structural pattern and kinematics of deformation in the region to the north of latitude 37?N, between the North Tabriz Fault and the MRF. We followed this goal through detailed fault mapping, structural field measurements, and fault-sli
NW-tending faults in Central Iran are expected to represent dominant dextral components due to their orientation with respect to the northward motion of the Arabian Plate with respect to Eurasia. However, previously published works, as well as the focal mechanism solution of the area's earthquakes, indicate evidence of sinistral kinematic along the major faults in Central Iran. Here we present detail structural kinematic data on the eastern part of WNW trending Kushk-e- Nosrat (KN) Fault zone to unravel the structural architecture and regional distribution of kinematic change at the northwestern margin of Central Iran zone. We classified fault data into two dextral and sinistral kinematic categories. Based on cross-cutting relationship and
Abstract Geometry and kinematics of deformation across the Nehbandan Fault System (NFS) have been studied in the Bibimaryam and Damdameh areas in the Sistan Suture zone (SSZ). Nearly vertical fault planes with sub-horizontal lineations and correlation of these faults analysis with anisotropy of magnetic susceptibility (AMS) indicates a predominantly transpressive regime including right-lateral strike-slip faults with reverse components in the region. An assemblage of en-echelon and doubly plunging folds with slip indicators, such as duplexes in their limbs, confirms progressive transpressive deformation. Accompanying hydrothermal alteration has created ideal conditions for reactivating shear fractures during
Structural inversion of strike–slip faults in response to plate kinematic changes and interactions of large–scale basement blocks is a significant phenomenon in continental collision zones. In the Alborz Mountains, at the northern margin of the Iranian Plateau, Late Cenozoic kinematic of major fault systems changed in the late Pliocene from dextral to sinistral strike–slip. This kinematic change has been attributed to the clockwise rotation of the rigid South Caspian Block. However, the spatial extent and distribution of this kinematic change toward the south and into the Iranian Plateau is controversial. Here we present a detailed structural analysis of the West Saveh fault system located at the northwestern margin of the Iranian Pla
Azadkuh region located in Central Alborz Range and comprises Paleozoic to Cenozoic rock units. The Azadkoh Fault in the north and the TF4 Fault in the south bounded the region. This study aimed to investigate structural events in the region as a part of central Alborz since Cretaceous. Investigation of structural evidence shows several geological events in Cenozoic at this part of Central Alborz range. Cretaceous volcanic overlay the Triasic-Jurasic Shemshak Formation as angular unconformity. In addition, the Paleocene Fajan conglomerate as angular unconformity overlay the Cretaceous volcanic or older rocks. The presence of Cretaceous rocks and the Karaj Formation within the Eocene basin bounding faults in which syn-sedimentary faults devel
Gardeneh-Shir zinc and lead deposit is located at 38 km southwest of Ardestan in Central Iran. The host rocks of this deposit includes carbonates of Middle Triassic Shotory Formation juxtaposed over Upper Triassic Naiband Formation by thrust faulting. The mineralization in these deposits is in the form of vein-veinlet, breccia and filling of karstic cavities with dolomitization and silicification and mainly controlled by Strike-slip faults with the normal component and normal faults with strike slip component those are cross cutting older generation of thrust faults. The results of fluid inclusion studies of on quartz and dolomite in Gardeneh-Shir deposits Area show a fluid with a salinity of 23.2-18.6% by weight of salt, temperature range
SE trending (S62E) and NE dipping (80NE) mylonitic foliation is the main structural feature developed in ~557-561Ma Deh-Zaman mylonitic granite in the N70˚E trending Kuh-e-Sarhangi shear zone at the northwest of the Lut Block. 35˚ plunge of the stretching lineation on this mylonitic foliation in combined with microstructural evidence, especially on feldspar crystals confirmed dominant sinistral shear with the little compressional component. Sinistral shear proposed to initiate after emplacement of the granitic body and deformed it at ~300-500˚C during Early Cambrian. Our new and detailed microstructural analysis indicates considerable overprinting of dextral shear on the former older sinistral shear in the Deh-Zaman mylonitic granite. Th
The sub-vertical fault planes with sub-horizontal slickenlines and correlation of these date with anisotropy of magnetic susceptibility indicates a predominantly transpressive regime including right lateral strike slip faults with reverse components in the Bibi-Maryam area. An assemblage of en-echelon and double plunge folds with slip indicators such as duplexes in their limbs confirms progressive transpressive deformation there. Accompanying hydrothermal alteration with transpression has created ideal conditions for reactivating shear fractures during late Cenozoic times that they record the last phase of tectonic activity. The sets of the shear fractures indicate an N025? direction of compression (σ1) that is compatible with the Plio-Qua
Cretaceous sedimentary sequence in the Yazdan area is consisting of four rock units as, from the old to the new, clastic-carbonate (Kc), carbonate (Kl), Shale and marl (Km) sequences, and Sandy limestone and sandstone (Kls). The Kls unit is host of ore mineralization in the study area and formed from four members. Ore mineralization in the Yazdan Deposit has occurred as a stratiform horizon in the sandstone units of the third member. Texture and structures studies, shown three ore facies with elemental zonation in the Yazdan Deposit. These ore facies includes, stringer zone, massive ore facies and the bedded ore facies. This ore facies formed from laminated and layered sulfide and sulfate minerals. Fluid inclusions studies represents 255-13
The Amiran anticline with about 50 km length is located in NW-SE of the Zagros fold and thrust belt and the Lurestan sub-zone. The aim of this study was to investigate the role of thrust and basement strike-slip faults on the structural geometry of this anticline. For this purpose, three cross-section perpendicular to the anticline axis have been constructed in the NW, central, and SE parts of the anticline. A basement thrust fault in the southwestern limb of this anticline and two upper (Amiran Formation) and Middle (Garau Formation) detachment levels affect the folding geometry and led to the formation of disharmonic folding. In addition to the thrust fault at the southern limb, an N-S basement strike-slip fault in the middle part of the
کوههای فراقون از نظر چینه شناسی کاملترین توالی سازندهای دوران پالئوزوئیک زاگرس از اردوویسین پیشین تا پرمین را در خود جای داده است، همچنین از نظر ساختاری گسل زاگرس بلند بعنوان برجستهترین ساختار منطقه حد جنوبی آن را مشخص کرده است. در این مطالعه برپایه انجام برداشتهای ساختاری و رسم برشهای ساختاری تحلیلی از الگوی تکامل ساختاری کوههای فراقون ارائه شده است. شواهد ساختاری و رسوبی نشان دهنده تشکیل گسل زاگرس بلند از س?
The structural geometry and kinematic variations along curved fold and thrust belts and their interaction with neighboring rigid basement blocks are not well understood. In this study, we present a structural mapping and stratigraphic analysis of the Talesh Mountains, Iran, to document the timing and evolution of this curved orogen due to collision with the South Caspian Block. NE and SW verging oblique slip thrust faults are the main structural features in the northern and southern parts of the mountains. The N-trending central part of the range is connected to the curved ends of the Talesh Mountains by a system of high angle reverse faults with right lateral strike-slip sense of motion. Restored cross sections indicate greater horizontal