Journal of Geology and Mining Research Vol. 2(7), pp. 170-182, December 2010 Available online http://www.academicjournals.org/jgmr ISSN 2006 – 9766 ©2010 Academic Journals
Full Length Research Paper
Neotectonic stress field and deformation pattern within the Zagros and its adjoining area: An approach from finite element modeling Md. Shofiqul Islam1,2* and Ryuichi Shinjo1 1
Department of Physics and Earth Sciences, University of the Ryukyus, Okinawa, Japan. Department of Petroleum and Georesources Engineering, Shahjalal University of Science and Technology, Sylhet, Bangladesh.
2
Accepted 23 August, 2010
In this study, finite element modeling (FEM) is performed to analyze the Neotectonic stress field of Zagros fold-and-thrust belt and its adjoining areas. Our modeling results predict that the study area has somewhat complex stress orientation, deformational fashion and faulting pattern under oblique convergence tectonic setting. The modeled results demonstrate that the displacement vectors within the Coastal plain, Persian Gulf, eastern part of Sanandaj-Sirjan-Metamorphic Zone have NE-ward direction, while the Main Recent Fault and some part of Sanandaj-Sirjan-Metamorphic Zone have N-ward and sometimes NE-ward direction. The modeled maximum horizontal compressive stress ( Hmax) orientation within the Lurestan, High Zagros Fault, Main Recent Fault and eastern Zagros Simple Folded Belt are predicted to have NE-SW, NW-SE and N-S, whereas the rest part of the study area displays mainly NE-SW. Fault pattern calculation of the study region predicts that strike slip faults are mainly present at shallow crustal level (up to 10 km), whereas thrust faults with strike-slip component are predominant at deeper crustal level (>10 km). Our modeling results are comparable with available data of focal mechanism solution, seismicity, GPS and world stress map (WSM). Thus we believe that modeling results can be used as a reference dataset, presenting to estimate overall stress condition, plate velocity and faulting pattern of an extensive area, because the other geophysical/geodetic data do not cover wide area of the region. Key words: Zagros fold and thrust belt, stress, focal mechanism solution, seismicity. INTRODUCTION The tectonic stress distribution is directly associated with plate movement and varies place to place over the Earth (Gowd et al., 1992). The convergent boundary condition is responsible for enormous heterogeneous stress field over inter-plate region (Rajendran et al., 1992). The Zagros Fold and Thrust Belt (ZFTB) is a part of the Iranian mountains (Figure 1), which are actively deforming due to shortening between the Arabian and Eurasian plates. The Arabia-Eurasia convergence began in Southern Iran with the ZFTB at end of Eocene
*Corresponding author. E-mail:
[email protected]. Tel: +81090-6636-4161. Fax: +81-098-895-8552.
(Hessami et al., 2001; Vernant et al., 2004). The convergence of Arabia with Eurasia (average motion Aegean relative to Eurasia is 20 - 30 mm/yr) is accommodated in large part by lateral transport within the interior part of the collision zone and lithospheric shortening along the Caucasus and Zagros Mountain belt (Reilinger et al., 2006). The deformation is taking place as an oblique convergence and strength of fault controlled by faults orientation (Vernant et al., 2006). As a part of Alpine-Himalayan mountain chain, the ZFTB extends for more than 1500 km in NW-SE direction from eastern Turkey to the Minab-Zandan-Palami fault system in the Southern Iran (Stocklin, 1974; Vernant et al., 2004). Geologic and geophysical studies on the ZFTB (Alavi, 1994, 2004 and 2007; Berberian, 1995; Hatsfeld et al.,
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Figure 1. Regional tectonic map of the Zagros fold-and-thrust belt (modified after Navabpour et al., 2007). UDMA = Urumieh-Dokhtar Magmatic Arc; SSMZ = Sanandaj-Sirjan Metamorphic Zone; MZT = Main Zagros Thrust; MRF, Main Recent Fault; HZF = High Zagros Fault; ZSFB = Zagros Simple Fold Belt; MFF = Mountain Front Fault; IZ=Izeh Zone; BFZ = Borazjan Fault Zone; IFZ = Izeh Fault Zone; KFZ = Kazerun Fault Zone. ZF = Zagros Foredeep; ZFF = Zagros Foredeep Fault; MSZ = Makran Subduction Zone. Black arrow indicates GPS convergence vector from Vernant et al. (2004).
2003; Bachmanov et al., 2004; McQuarrie, 2004; Sepehr, 2004; Sherkati et al., 2005; Hessami, 2006; Kalviani et al., 2007; Navabpour et al., 2007; Stephenson et al., 2007) have provided improved understanding the structure, stratigraphy, tectonics and crustal movement of the region. Despite of deployment of a lot of geodetic instruments, in addition to geophysical works, all these studies can describe about only several tens of year record. There still is a scope to investigate the study area using numerical simulation method with appropriate proxies. In this paper, we aim to reproduce the study area’s stress distribution, deformation and faulting pattern with help of finite element method (FEM) simulation program. We believe such data can help us to better interpret regional tectonics of the study area. Geological and tectonic background The ZFTB in Iran (Figure 1) is a consequence of the Alpine Orogenic events in the Alpine-Himalayan Mountain range that extends in a NW-SE direction from eastern Turkey to the Strait of Hormuz in the Southern Iran
(Navabpour et al., 2007). The High Zagros Belt (HZB) is an imbricated zone that marks the northeastern part of the Arabian passive paleomargin which separates Main Zagros Thrust (MZT) and Main Recent Thrust (MRF) (Berbarian, 1995; Navabpour et al., 2007). The SanandajSirjan Metamorphic Zone (SSMZ) and the UrumiehDokhtar Magmatic Assemblage (UDMA) are two major parallel domains which are interpreted as the product of northeast-dipping subduction processes (late JurassicCenozoic) of Neo-Tethyan oceanic crust under the Iranian continental margin (Berbarian and King, 1981). The Zagros orogenic belt was affected the opening of the Red sea and the closure of Neo-Tethys accompanied by convergence between Arabian plate and Eurasia in late Cretaceous to Miocene. First stage of deformation, alkaline pluton had been intruded at SSMZ during the Mesozoic as Andean-type active margin (Agard et al., 2005). The first closing stage of the Neo-Tethys began during the latest Jurassic to early Cretaceous. Northeastward plate subduction beneath the Iranian plate caused intense magmatism, forming the UDMA. The subsequent major obduction event (ca. 100 - 70 Ma) occurred at the SW margin of the Neo-tethys. The island-
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arc signature of the Harsin/Sahneh ophiolite suggests that the obduction could have developed from the volcanic arc setting during Cretaceous as modeled by Boutelier et al. (2003). After emplacement of ophiolite, the Afro-Arabian continent collided with the UDMA in Middle Maastrichtan (approximately 68 Ma) (Alavi, 2007). In the superseding Iranian plates, the collision increased differential rotation rate of the Iranian micro-continent, and the collisional mountain building has continued with variable intensity to the present (Alavi, 2004). Morphotectonic units Urimiah-Dokhtar magmatic assemblage (UDMA) The UDMA is a relatively narrow (50 - 80 km wide), linear belt of intrusive and extrusive rocks (Alavi, 2007). Alavi (1994) reports that northeastern side of UDMA is thrusted onto the associated retroarc/retroforland deposits and transected by number of right-lateral strike-slip faults. The assemblage in this zone includes a thick (approximately 4 km) pile of calc-alkaline and highly potassic alkaline andesites, dacites, andesitic basalts, trachyandesites, and rhyolites intruded by diorites and various granitoids that are associated with extensive pyroclastic layers (Alavi, 2007). The sanandaj-sirjan metamorphic zone (SSMZ) The SSMZ lies to the southwest of the UDMA and is considered as a part of Iranian Continental block (Stocklin, 1968). This zone is wide (150 – 250 m) and has structural trends which are parallel to the rest of the Zagros orogenic elements. The northeastern part of the zone contains a series of elongated depressions that are well developed parallel to the southwestern boundary of the UDMA. Rocks of SSMZ are of Phenerozoic age and considered to be part of Precambrian basement. In some places, thin section slices of coarse pyroclastics and tuffaceous layers of Tertiary age (Alavi, 1994) have been found. Volcanic rocks such as basalt and rhyolite are found inter-layered with Carboniferous-Permian-Lower Triassic well-beded, shallow-water, shelf siliciclastic and carbonate (Alavi, 1994). The Zagros fold-thrust belt (ZFTB) The ZFTB has an average width of approximately 300 km that extends parallel and to the southwest of the Zagros imbricated Zone (Falcon, 1974). From the spectacularly displayed by satellite images the whole Zagros is visible as en echelon “whale-back” (Alavi, 2007). In the ZFTB, the sequence is composed of approximately 7 - 12 km of uppermost Neoproterozoic and Phanerozoic strata, which
is intruded by nearly 120 salt diapers in the southeast. The Zagros Foredeep (ZF) and the Dezful embayment The ZF is enclosed to the northeast by the Main Recent Fault (MRF) and to the southwest by the Zagros Foredeep Fault (ZFF), which marks the northeastern edge of alluvial covered coastal plain of the Persian Gulf (Berberian, 1995). Berberian (1995) also reports that the formation of the ZF was associated with motion along the MFF and uplift of the Simple Fold Belt. The ZF consists of the Fars Group sediments (Gachsaran, Mishan and Agajari Formations), associated with elongate and symmetrical folds. The important phenomenon in this foredeep is sheared off from the subsurface EoceneOligocene Asmari Limestone base along decollment thrust in the Gachsaran Evaporites and Salt tectonics (Sherkati et al., 2005). The decollement levels separate lithotectonic units that accommodate shortening in various ways during folding (Sherkati and Letouzey). There is a thick sequence of the Lower Miocene to Pleistocene syn-orogenic molasses cover (AghajariBakhtiari formations) within this belt. The Dezful embayment appears to be a discrete structural unit, with boundaries defined by Dezful embayment fault to the north, the Kazerun-Borazjan transverse fault (KFZ) to the east and southeast. It is a sedimentary basin with pronounced subsidence and thickening of the postEocene-Oligocene Aghajari Formation with more than 3 km thickness (Berberian, 1995). Sherkati and Letuozey (2004) referred that the variation of sedimentary thickness in the Dezful emabyment is controlled by N-S and NW-SE faults. The Zagros coastal plain The Zagros coastal plain is a narrow feature delimited to the north by Zagros Foredeep fault (ZFF) and to the south by the Persian Gulf and the Zagros–Arabia boundary. This zone consists of alluvial deposits. The Persian gulf (PG) and Mesopotamian lowland The PG and Mesopotamian lowland unit lies south and southwest of the Zagros coastal plain. The PG with an 2 area of about 226,000 km , is a shallow epicontinental sea with a tectonic origin. Geodynamics of the study area According to NUVEL-1A plate tectonics model, the Arabian plate is moving N13°E at a rate of approximately 31 mm/yr relative to Eurasia at longitude of 52°E (DeMets
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Figure 2. Simplified model geometry from Figure 1 with boundary condition.
et al., 1994). However, the recent GPS data reveal the approximately 20 mm/yr motion of the Arabia with respect to stable Eurasia with the same direction of N13°E (McQurrie et al., 2000; Sell et al., 2002; Vernant et al., 2004; Hessami, 2006; Reilinger et al., 2006). The GPS study indicates that east of KFZ has 13 - 22 mm/yr velocity toward N7±5°E, whereas the west of KFZ has velocity of 14 - 19 mm/yr toward N12±8°W (Hessami, 2006). Walpersdorf et al. (2006) show that the GPS velocity in northern Zagros is fairly complex, particularly near Main Recent Fault (MRF) and orientation of velocity is toward NW direction with magnitude of approximately 2 mm/yr. The historical and instrumental seismicity in Iran suggests that an intercontinental deformation concentrated in several mountain belt surrounding relatively aseismic blocks like central Iran, Lut and South Caspian block (Vernant et al., 2004). The strain distribution is different in Central Zagros with respect to North Zagros. In Central Zagros, the compressional axes are parallel to each other and perpendicular to fold axes, whereas North Zagros exhibits the varied orientation of compressional axes (Walpersdorf et al., 2006). Moreover,
Navabpour et al. (2007) infer that a N-S compression (parallel to plate convergence) along the MRF and a NESW compression perpendicular to fold axes across the ZSFB. METHODOLOGY In the study area, we firstly selected a suitable map (taken from Novabpour et al., 2007); the map is simplified (Figure 2) and used for simulation considering elastic continuum. The entire study area is located between latitude 25 - 35°N (1100 km) and longitude 45 57°E (1220 km). The area is divided into small triangular elements or domains. A mesh is generated with assemblages of 2262 elements and 1200 nodes. The simulation is performed by using the FE software package developed by Hayashi (2008). Model set up Nine rock domains are considered in this study (Figure 2), on the basis of morphotectonic units and similarity of lithologic characteristics of the study areas described in earlier. Unit 1 consists of PG, DE and Strait of Homuz and these are considered to have similar lithology. The MFF and BFZ are included in unit 2, while unit 3 also represents a part of MFF. Unit 4 composed of
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Table 1. Rock layer property of different domain of the model.
Layers 1 2 3 4 5 6 7 8 9
Density 3 (gm/m ) 2200 2000 2000 2400 2000 2700 2000 2000 2900
Vp (km/s)
Young’s modulus (GPa)
Cohesion (MPa)
Internal angle friction (Degree)
4.7 4.0 4.0 5.6 4.0 5.8 4.0 4.0 7.5
30 1 1 50 1 55 1 1 60
17 10 10 14 10 18 10 10 27
34 12 12 35 12 35 12 12 38
Poisson’s ratio is 0.25.
Lurestan, IZ, Shiraz and FARS Arc in folded Zagros. Unit 5 represents HZF and unit 6 is HZB. Units 7 and 8 indicate MRF and MZT, respectively. Unit 9 covers the entire area of Central Iran (CI).
side of the model are considered owing to Makran subduction and Anatolian subduction motion, respectively. North side is fixed and is to be considered as Eurasian plate.
Rock layer property of the model
RESULTS
The deformation within the ZFTB is mainly brittle type (Navabpour et al., 2007). In order to incorporate the brittle deformation, we adopt the rock parameters from Clark (1966), Hatzfeld et al. (2003), and Kaviani et al. (2007). The prime mechanical properties of different layers such as density, Young’s modulus, Poisson’s ratio and cohesion are used in the simulation (Table 1). The density values are taken from Clark (1966) and Paul et al. (2006). We calculate the Young’s modulus by the following equation (1) (Goodier, 1970; Hayashi, 2008),
E = ρV p
2
(1+ υ )(1− 2υ ) (1− υ )
(1)
Where E = Young’s Modulus, Vp is P-wave velocity, is density, and is Poisson’s ratio. We use the value of 0.25 for Poisson’s ratio during calculation. P-wave velocity is taken from Hatzfeld et al. (2003) and Kaviani et al. (2007). Two other physical parameters such as cohesion and internal angle of friction have been taken from Clark (1966).
Boundary condition The Zagros mountain belt is the active mountain building stage due to collision between the Arabian Plate and Iranian sub-plate. Folding and corresponding reverse faulting started Miocene in a compressional stress regime that was oriented NNE (Navabpour et al., 2007). Navabpour et al. (2007) also proposed that the HZB underwent two post-fold strike-slip stress regime under two distinct NNE and N-S compression in the late Miocene–early Pliocene and post Pliocene, respectively. The movement of Arabian Plate is considered to be the main driving force of crustal deformation within the study area. Other aforesaid geodynamic settings are also reflected in the boundary condition (BC) as shown in Figure 2. We impose oblique convergent to the south and west sides with some portion of southeast and northwest side, and most of the eastern side keep free to move along both x and y direction. The oblique convergent of the some portion of southeastern and northwestern
Considering homogeneous elastic rheology and assuming 25 mm/yr oblique convergent, we imposed 500 m (for 20,000 years), 1000 m (for 40,000 years) and 2000 m (for 80,000 years) displacements in the model, to simulate present-day displacement vector, tectonic stress field, and faulting pattern of the study area. We present our simulated results on following topics: (a) displacement vector, (b) Hmax orientation and (c) faulting pattern of the study area. Displacement vector Northward displacement vector is found within the study area under given boundary condition (Figure 3b). The model results displays similar displacement vector (NNE) except SSMZ, CI and MZT. The CI shows uniform displacement vector with smaller magnitudes. Eastern part of SSMZ shows N or NE direction but other parts show NW or WNW. MRF exhibits greater and almost similar direction in displacement vector as have observed in PG and DE. Hmax orientation
NE-SW maximum horizontal compressive stress ( Hmax) orientation is predicted from the modeled result for most of the part of model (Figure 4b). The modeled result also suggest that the Lorestan, HZF, MRF and eastern part of the ZSFB display complex and with multiple stress orientation. The Hmax orientation is predicted in the Lurestan to be having N-S/NNE-SSW, whereas around
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Figure 3a. GPS velocity of the study area.
MRF (including its western-side and eastern-side), it is NW-SE. The CI displays NE-SW stress orientation within the model. Fault pattern Figures 5a - 5c show the modeled fault pattern of the study area at depth variation. We modeled fault pattern for the depth of 1, 10 and 30 km. It is found from calculation that strike-slip fault is dominant in shallower depth (up to 10 km), while thrust fault becomes significant with increasing the depth. At 1 km depth (Figure 5a), MSZ, MZT and MRF are predicted to be thrust fault, and the entire ZFTB shows strike-slip fault. Some strike-slip fault also is predicted in the southern part of CI from model result. For 10 km depth (Figure 5b), the thrust faults are associated with strike-slip fault all over the ZFTB. However, Lurestan and Fars Arc are predominated by thrust faults. For greater depth at 30 km (Figure 5c), thrust faults are dominant in the ZFTB. The KFZ, BFZ, FZ, HZF, and eastern side of MRF display strike-slip faults. Moreover, southern CI shows thrust fault along with strike-slip component.
DISCUSSION AND CONCLUSION Recent tectonic activity in the ZFTB is the consequence of continental convergent between Arabia and Asia (Hessami, 2002). To analyze the study area, we imposed realistic boundary condition into our plane stress model with appropriate rheological proxies. We consider that simulated result with given boundary condition is fitted to depict study area more logically and precisely. The GPS velocity (Figure 3a) (Hessami et al., 2006) and our simulated displacement vector direction (Figure 3b) are comparable. The modeled result exhibits NE-ward displacement vector, except for the CI, SSMZ and MZT. The CI shows uniform displacement vector with the smallest magnitudes. Eastern part of SSMZ shows N or NE direction. MRF region shows greater and almost similar magnitude in displacement vector than PG and DE regions. So it is obvious that modeling results are consistent with GPS reading. The High Zagros Belt (HZB) of Fars region is characterized by a change in state of stress from compressional to strike slip regime which is indicated by the orientation of maximum horizontal compressive stress ( Hmax) toward NE-SW or N-S (Navabpour et al., 2007).
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Figure 3b. Modeled displacement vector of the study area.
Navabpour et al. (2007) also suggested that southwestern Zagros (HZF) shows similar but almost N-S orientation of Hmax that is parallel to the plate convergent trend along MRF and NE-SW across ZSFB and perpendicular to the fold axes. They analyzed 31 earthquakes focal mechanism solution, 13 of which are near the MRF having N-S Hmax orientation, and the other 18 events have NE-SW in the Hmax orientation southwestern part of Zagros (ZSFB, MFF, DE). Based on fault slip data (Authemayou et al., 2005; Navabpour et al., 2007), N-S stress direction of compression is revealed in the HZB of interior Fars and southeastern MRF. In the World Stress Map (WSM) (CASMO, 2008), the orientation of present-day Hmax is oriented in NE-SW direction in the High Zagros, Shiraz and eastern part of CI (Figure 4a). Fars arc displays NNE-SSW and N-S orientation of Hmax, whereas HZB shows NW-SE direction. East of the Fars arc and area near to Makran subduction show multiple Hmax orientation like NE-SW, N-S and NW-SE. Our modeled result (Figure 4b) suggests that most of the area displays NE-SW
orientation of Hmax, whereas Lurestan, HZF, MRF and eastern part of ZSFB show different stress such as NESW, NW-SE/N-S. Eastern side of MRF, northern part of HZB and east of HZF show NW-SE Hmax orientation. Lurestan and eastern part of ZSFB show N-S Hmax orientation. From the comparison (Figure 4), it is evident that our simulated results seen to be consistent with both the observed focal mechanism and the WSM data. The ZFTB and Iranian plateau are characterized by pure left-lateral strike slip faulting with recent volcanism and high surface elevation along the Alpine earthquake belt (Reilinger et al., 2006). Tectonic studies revealed that this area has a very high density of active and recent faults and that many of these fault systems are master blind thrust faults, being those have been responsible for destructive earthquakes and a serious seismic hazard to local population (Berberian, 1995). Earthquakes data of Iran indicate that most activity is concentrated along the ZFTB, whereas less activity is observed in central and eastern Iran. The distribution of historical and instrumentally recorded seismic events shows broadly
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Figure 4a. World stress map.
Figure 4b. Modeled
Hmax orientation.
similar pattern, with concentration of epicenters in the Zagros Mountain, although few historical earthquakes are
recorded at the desert in the central and eastern Iran. The relatively high level of seismicity within ZFTB and
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Figure 5a. Modeled fault pattern for 1 km depth.
Figure 5b. Modeled fault pattern for 10 km depth.
HZB indicate that these are zones of the most active faulting and deformation (Figure 6a). Our modeled failure elements also indicate similar result of the study area (Figure 6b). However, the majority of the large earthquakes can be associated with Holocene scraps and
Neotectonic features of the region (Walker and Jackson, 2004). Most focal mechanism solution of earthquakes (Figure 5d) in the ZFTB region indicates the presence of active reverse faults in the uppermost part of the Arabian
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Figure 5c. Modeled fault pattern for 30 km depth.
Figure 5d. Observed focal mechanism solution.
basement, beneath the Hormuz Salt Formation (Hessami, 2006). Berberian (1995) explains that the
active Mountain Front Fault is considered to be a major seismogenic reverse fault in the Zagros basement. Focal
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Figure 6a. Distribution of Earthquake of the study area.
Figure 6b. Distribution of failure elements within the model.
mechanism solution also indicates that deformation in the Zagros basement is shortening and thickening through numerous faults (Alavi, 2004). Shortening components
associated with the strike-slip faults results in widespread trust faulting (Walker and Jackson, 2004). Our simulated results are consistent with existing focal
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mechanism solution and seismicity of the study area. The WSM (CASMO, 2008), which is referred from focal mechanism solution, shows that east of the Fars arc-near Makran subduction region are associated with thrust and strike-slip faults, whereas Fars arc and Shiraz area show only thrust fault. The KFZ and IFZ show strike-slip faults and MFF shows thrust fault. West of the Shiraz and eastern CI show combination of strike-slip and thrust faults at greater depth (30 km). Our modeling results also show similar faults in the study area at different depth as described earlier. Our numerical simulation can reproduce a huge number of Hmax and displacement vector over the entire study area which are not presented by any other researchers yet. Our modeling results also are compared well with existing geophysical and geodetic data, which revealed that our simulated results are realistic. Therefore, using these model results, we can estimate stress state and deformation pattern in wide area. ACKNOWLEDGEMENTS Authors would like to express gratitude to the Ministry of Education, Culture, Sports, Science and Technology of Japan (Monbukagakusho) for financial support under Special Marine Science Program of Graduate School of Engineering and Science, University of the Ryukyus, to capable this research. We thanks to Mitsubishi Scholarship Foundation for financial support to complete this work too. We are grateful to M. Nakamura for preparation of seismic and focal mechanism solution maps of the study area. We thank two anonymous reviewers for their constructive comments and suggestions on the manuscript, which significantly improve this paper. REFERENCES Agard P, Omrani J, Jobilet L, Mouthereau F (2005). Convergent history across Zagros (Iran): constraints from collisional and earlier deformation. Int. J. Earth Sci. 94(3): 401-419. Alavi M (1994). Tectonics of the Zagros orogenic belt of Iran: new data and interpretations. Tectonophy., 229(3-4): 211–238. Alavi M (2004). Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution. Am. J. Sci., 304: 1–20. Alavi M (2007). Structures of the Zagros fold-thrust belt in Iran. Am. J. Sci., 307: 1064–1095. Authemayou C, Bellier O, Chardon D, Malekjade Z, Abbasi M (2005). Role of the Kazerun fault system in active deformation of the Zagros fold-and-thrust belt (Iran). C.R. Geosci., 337(4): 539-545. Bachmanov DM, Trifonov VG, Hessami KhT, Kozhurin AI, Ivanova TP, Rogozhin EA, Hademi MC, Jamali FH (2004). Active faults in the Zagros and central Iran. Tectonophy., 380(3-4): 221-241. Berberian M (1981). Active faulting and tectonics of Iran. In: H.K. Gupta and F.M. Delany, Editors, Zagros–Hindu Kush–Himalaya geodynamic evolution. American Geophysics Union, Geodynamic 3: 33–69. Berberian M (1995). Master “blind” thrust faults hidden under the Zagros folds: active basement tectonics and surface morphotectonics. Tectonophy., 241(3-4): 193–224. Berberian M, King GCP (1981). Towards the paleogeography and
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