Earth Sciences, Adelaide University, Adelaide, Australia
Geology, Tarbiat Modares University, Tehran, Iran
Geology, Mashhad Ferdowsi University, Mashhad, Iran
Ali Yassaghi, born in 1961, Iran, received B.Sc. and M.Sc. degrees in Geology and Structural Geology from Mashhad University and Tarbiat Modares Uinversity in 1987 and 1990, respectively. His Ph.D. degree in Structural Geology from Adelaide Uinversity, Australia in 1998. Since 1998 he has been an academic member in the Departemet of Geology at Tarbiat Modares University, teaching graduate courses in Structural Geology. Prof. Yassaghi?s research interests includes: Geometry, kinematics and dynamic analysis of fault zones in Iranian Mountain Ranges; Structural Geology of Zagros Fold and Thrust Belt and its reservoir potential analysis; Evaluation of seismic/aseismic (Friction and Faulting) behavior of fault rocks, Geological investigation of underground spaces. He has also supervising/advising M.Sc./Ph.D. theses on these research projects. Together with his students, he has published more than 100 papers in the peer-reviewed journals. He has also published a book on topic of ?Principles of Deformation in Tectonics? in Persian. Prof. Yassaghi has been among the founding board of the Iranian Society of Tectonics and a member of the Board of Directors of this society. He has also been a member of the Editorial Board of Journal of Geopersia, and Iranian Journal of Oil and Gas Science and Technolog.
Interpretation of reflection seismic profiles, sequential restoration, and physical modelling are presented to understand the kinematics of salt flow and diapirism in the Eastern Persian Gulf, offshore Southern Iran. Salt tectonics in this area result from the overlapping Ediacaran–Early Cambrian Hormuz Salt, which is regionally present, and Oligocene–Early Miocene Fars Salt, which is locally developed. The Hormuz and Fars salts began flowing at Cambrian(?) and Early Miocene times, respectively. Diapirs fed by the Hormuz Salt rose passively during Palaeozoic and Mesozoic times and were rejuvenated by contractional deformation events in the Cenozoic. Fars-Salt structures exist either as salt walls and anticlines around those diapirs of H
The Ziar area is located in the central part of the Alborz range. Field investigation and structural mapping of faults cut Mezozoic to Late Cenozoic (Pliocene-Quaternary) rocks in the area have led to identification of the NW- and NE- trending fault sets. Slickenlines, fault steps and riedel shear fractures are mainly applied as kinematic indicators for analysis of the faults mechanisms. The NW-trending reverse faults with left-lateral strike-slip kinematics and positive flower structure geometry (such as Golezard Fault) is the first set. This set cut through all rock formations up to Plio-Quaternary are proposed to develop during the northeastern oblique transpression deformation governs the Alborz during the final collision of the Arabian
In this paper, the effect of transverse faults on the orientation, density and fractures apertures and amount of mud loss is investigated in Asmari Formation as a major oil reservoir in Zagros folded belt zone, Iran. This carried out on three selected anticlines as the surface Kuh-e-Kamarab, and subsurface Marun and Aghajari oil fields. Subsurface data on fracture characteristics were obtained from Image logs, mud losses, and reported drilling data. These are compared with outcrop fracture characteristics gathered from fieldwork and satellite image interpretation. The results show that fracture orientations are almost identical in both outcrops and subsurface data, whereas the fractures density and aperture are different along and across th
Salt tectonics in the Eastern Persian Gulf (Iran) is linked to a unique salt‐bearing system involving two overlapping ‘autochthonous’ mobile source layers, the Ediacaran–Early Cambrian Hormuz Salt and the Late Oligocene–Early Miocene Fars Salt. Interpretations of reflection seismic profiles and sequential cross‐section restorations are presented to decipher the evolution of salt structures from the two source layers and their kinematic interaction on the style of salt flow. Seismic interpretations illustrate that the Hormuz and Fars salts started flowing in the Early Palaeozoic (likely Cambrian) and Early Miocene, respectively, shortly after their deposition. Differential sedimentary loading (downbuilding) and subsalt basement
Dimeh spring emerges from the Zarab Anticline, Zagros Mountains (Iran), and the mean annual discharge is~ 2.5 m3/s. The region has a semi-arid climate. A rainy season starts in October and usually ends in May, with snowfall common on the higher ground between December and February. The mean annual precipitation of the study area is about 1357 mm (Karimi Vardanjani et al., 2017). However, preliminary evaluations suggest that the spring recharge is from the Zarab Anticline, but in several previous dyes tracing tests, the dye was injected in the Zarab anticline was not seen in the Dimeh Spring (Janparvar, 2001; Pourab Co, 2012). Then, in order to find the catchment area of this spring, the present study has focused on tectonic aspects.
The mechanical properties of incompetent rocks play a crucial role in controlling the deformation style of fold-thrust belts. Disharmonic folding occurs due to the act of detachment layers, in which surficial fold shapes doesn’t reflect their deeper geometry. The Gachsaran Formation is the most significant detachment layers across the Zagros folded belt zone. In this study, field data, interpretation of subsurface data (2D seismic lines, UGC maps and well data) together with surface geological mapping, permit to measure crestal shift of anticlines, Aghajari, Pazanan, Rage-sefid, BibiHakimeh, Sulabdar and Nargesi in the southern Dezful Embayment. The results show the effect of the Gachsaran Formation on the folding style. Since the Gachsar
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
The integration of biostratigraphy, strontium isotope stratigraphy, and magnetostratigraphy allowed for the precise dating of the >3.0-km-thick marine to non-marine foreland sedimentary succession within the Dowlatabad growth syncline along the Frontal Fars arc in the Zagros Fold Belt that extends from eastern Turkey to southern Iran. This area was the missing link to complete the dating of syntectonic deposits in the Fars arc and quantify the migration of sedimentary belts as well as the propagation of folding across the entire Mesopotamian foreland basin. Both are essential for defining the interplay of basin evolution and sequence of folding. Deposition of the foreland marine marls in the Mishan Formation started at ca. 11.5 Ma.
Frictional heterogeneities within fault zones depend strongly on lithology as well as shear fabric and strain localization structures. Here we investigate the impact of fault rock composition and shear fabric on friction constitutive properties for mature High Zagros (Iran) fault rocks. We present field observations along with results from friction experiments on intact and powdered fault rock from carbonate, quartzofeldspathic and schist. We measured frictional strength and rate/state dependence over normal stresses from 25 to 100 MPa and shear slip velocities from 3 to 300 μm/s. The sliding friction coefficients of intact fault rocks are lower than their powdered equivalents. The foliated quartzofeldspathic and lensoidal carbonate ro
In this work, kinematics of the Izeh fault zone as one of the major transverse faults in Zagros and its influence as younger deformation on the belt structure are analyzed. Izeh fault zone with 165 trend in Azimuth and right-lateral strike-slip kinematics, cross-cuts the High Zagros and the Folded Belt zones of Zagros fold-thrust belt. Surface deformation of Izeh fault zone on the cover sediments includes changes on the trend of the belt major structures and development of minor folds and faults that are developed independently or overprinted on the belt major structures. Detailed structural mapping showed the presence of five major restraining step-over zones between the mapped right lateral strike-slip en-echelon faults alo
Field observations on the effect of fault smearing on spatial development of underground water and its inrush in amount of 4m3/sec into underground space.
We reveal transient surface deformation following the 2017 Mw7.3 Sarpol Zahab (Iran) earthquake using Interferometric Synthetic Aperture Radar (InSAR) measurements. Based on the coseismic interferograms derived from the Advanced Land Observing Satellite‐2 (ALOS‐2) data, the preferred slip model of the earthquake has a centroid depth of 14.5???4?km and suggests that a basement fault is most likely responsible for the 2017 earthquake in the northwest Zagros fold‐thrust belt zone. Two slip asperities with a maximum slip of 6?m separated by 16?km are observed in the best fitting slip model. The accumulated afterslip in the first month after the mainshock determined from the Sentinel‐1 postseismic interferograms reveals a slip distribu
Central-East Iran has numerous active Quaternary faults. This paper focuses on the analysis of geomorphic and structural characteristics of the Kalmard fault zone, including major NE–SW striking fault segments that cuts across the basement and the sedimentary cover in the Ozbak-Kuh area of Central-East Iran. Because of the absence of definite earthquakes through the Kalmard fault zone in contrast to other parts of Central Iran, we used morphotectonic methods in combination of structural studies to evaluate active tectonics of this area. Detailed structural assessment of satellite images and analysis of geomorphic indices, together with field surveys allowed us to evaluate the recent tectonic activity and support a Quaternar
The Zagros fold-and-thrust belt is the product of oblique collision between Arabian and Eurasian plate which is an important orogenic belt for studying crustal deformation and seismogenic faults. Previous studies suggest that the M> 7 big earthquake occurred in the deep basement related to mid-crust thrusting with a deep d?collement fault located at 20-25 km depth resulted from a ductile shear zone. However, the moderate earthquakes (Mw 5.5-6.5) often occur in sedimentary cover with a thickness of about 10 km. The interface of basement and sedimentary cover is Hormuz Salt layer which is the major d?collement fault of the Zagros fold-and-thrust belt. The crustal deformation is decoupling between the basement and sedimentary cover, thus the c
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
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