Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Sarkarinejad, Khalil; Samani, Babak; Faghih, Ali; Grasemann, Bernhard; Moradipoor, Mahshid

doi:10.1016/j.jseaes.2009.12.015

Cited by 36 publications

(5 citation statements)

References 55 publications

(69 reference statements)

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“…The mélange of Cyprus is another example produced during the Palaeocene-Early Miocene initial collision of Arabian and Eurasian plates (Krylov, Kaleda, & Bragin, 2005). During the Late Miocene-Pliocene times in the Zagros region, the angle of collision between the Eurasian and Arabian plates was approximately 25° and the σ 2 axis was vertical indicating a strike-slip stress regime ( Figure 13; Barrier et al, 2014;Navabpour et al, 2007;Sarkarinejad, Samani, Faghih, Grasemann, & Moradipoor, 2010). Two shortening phases were recognized after Miocene times (Agard et al, 2005;Navabpour et al, 2007 1977): A Miocene-Pliocene compressional regime with a NE-SW trend occurred during the first stage of continental collision, followed by the Pliocene-Recent shortening with a N-S trend.…”

Section: Miocene Mélangesmentioning

confidence: 99%

Mélange development in the Neyriz region of Zagros Orogen, Iran: Record of convergence and collision in the Neotethyan Realm

et al. 2020

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Mélanges are formed by sedimentary, tectonic and diapiric processes and are generally found in collisional belts. The Zagros Orogeny provides an intriguing geological laboratory for the study of mélange-forming processes during the progressive tectonic evolution of the Neotethys Ocean. Different types of tectonic and sedimentary mélanges occur in specific structural positions within the Zagros orogenic belt in the Neyriz Region (Iran). Based on their block-in-matrix fabrics, and tectonostratigraphic positions, we differentiated 14 different mélange types, which mark different episodes of the tectonic evolution of the Neyriz Region from the Cretaceous subduction to the Miocene collision. The Cretaceous subduction stage is recorded by volcanic-sedimentary mélanges (Mv). Sedimentary mélanges characterized by megabreccia from the Cretaceous limestone (Ms1) and Eocene polymictic megabreccia (Ms2) represent epi-nappe mélanges formed during the Palaeocene-Eocene in wedge-top basins. The ophiolite emplacement in the Oligocene resulted in local extensional tectonics in the upper part of the ophiolitic nappe, and deposition of a polymictic megabreccia (Ms3, Ms4). As the final production of the Neotethys Ocean closure and the Eurasian-Arabian collision, the sedimentary mélanges characterized by different types of chaotic rock units (Ms5, Ms6, Ms7 and Ms8 facies) were developed in front of the Cretaceous-Eocene nappes due to growth of the orogenic wedge in the Miocene. Our findings indicate that the recognition and distinction of different types of mélange may provide additional constraints for a better understanding of the tectono-sedimentary evolution of the Neotethyan region.

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Section: Miocene Mélangesmentioning

confidence: 99%

Mélange development in the Neyriz region of Zagros Orogen, Iran: Record of convergence and collision in the Neotethyan Realm

et al. 2020

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“…This phase of deformation occurred contemporaneously with the regional metamorphism in the SSMZ. The foliation is the most important structure developed in this stage (Sarkarinejad et al, 2010;Sheikholeslami, 2015) The deformed Precambrian unit consists of schist, phyllite, and slate, exposed extensively in the east and south-east of the study area. The ribbon of meta-Rhyolite, metamorphosed acidic tuff and ignimbrite lie parallel to this Precambrian unit (Fig.…”

Section: D1 Dynamo-thermal Regional Deformationmentioning

confidence: 99%

Constraining of strain ellipsoid shape from sectional data in the Au bearing shear zone west of Iran

Behyari¹

2019

Acta Geodynamica Et Geomaterialia

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Ductile shear zone recorded valuable data about the progressive deformation and geodynamic setting of the earth crust. Analysis of the strain ratio on the deformed quartz grains in the samples of the Zagros orogenic shear zone indicated generally most of the strain ellipsoids shape are prolate and developed under constructional strain regime. Principal axes of the strain ellipticity ratio varied in the range between 2.04 to 3.12, shear strain magnitude analysis indicated ε s are between 0.6 to 1.3. Strain ellipsoid shape also revealed the propagation of the shear zone could not be coeval with the continental collision because in the collision region expected the ellipsoid shape to be oblate. Flattening strain regime in the Zagros Orogeny contemporaneous with the collisional event (D1 phase) and widespread in the Sanandaj-Sirjan Metamorphic Zone. Constructional conditions and prolate strain ellipsoid could be related to the post-collisional deformation phase (D2 phase). In this event stretching and shearing localized in the ductile shear zone and transtension structures superimposed on the former transpression structures. The deformation followed by third phase and brittle event (D3 phase) and caused to the propagation of veins. These veins somewhere cut the foliation and in the other place are parallel to foliation plane.

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“…2). The study area has been sandwiched between two major thrusts due to the Zagros Thrust System and shows the geometry of a transpressional shear zone (Sarkarinejad et al 2010 greenschists, and quartzites. Figure 3 shows the geological map of the study area.…”

Section: Geological Settingmentioning

confidence: 99%

“…Volume change during deformation can affect the shape of the finite strain ellipsoid (Ramsay and Wood 1973). In the study area, the lack of prominent veining implies that the volume change is small (Sarkarinejad et al 2010). Therefore, throughout this analysis, it has assumed constant volume deformation.…”

Section: Stereographic Analysis Of Foliation and Lineationmentioning

confidence: 99%

Strain analysis using structural elements and geometry of surfaces of no finite longitudinal strain

Samani

2015

Arab J Geosci

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In this research, using structural elements and the geometry of surfaces of no finite longitudinal strain, crustal shortening and strain analyses have been carried out between two thrust faults in the Khon-Khoreh area in the north of Dehbid. The direction of the principal axes of the finite strain ellipsoid was defined using stereographic analyses of pole of foliation and lineation. With separation of shortening and longitudinal strain domains, the geometry of surfaces of no finite longitudinal strain was determined in 3D. The results of stereographic analyses and angular relations of surfaces of no finite longitudinal strain on the XZ and XY principal planes of strain ellipsoid show the amounts of 2Φ angle as: 48°< 2Φ XZ <58°and 75°<2Φ XY <82°. Results show three axial prolate strain ellipsoids in the study area. Using calculated angles and R/2Φ nomogram, the amount of finite strain in the principal planes of strain ellipsoid (R XZ and R XY ) and natural logarithmic strain (ε) was determined in the study area. With application of kinematic vorticity analysis, the amount of crustal shortening was determined to be about 30 to 60 % in the study area. Finally, it reveals that the amounts of finite strain ratios, natural logarithmic strain, and increment in the prolate shapes of strain ellipsoid increased with decrease in distance from the thrust faults.

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Implications of strain and vorticity of flow analyses to interpret the kinematics of an oblique convergence event (Zagros Mountains, Iran)

Cited by 36 publications

References 55 publications

Mélange development in the Neyriz region of Zagros Orogen, Iran: Record of convergence and collision in the Neotethyan Realm

Mélange development in the Neyriz region of Zagros Orogen, Iran: Record of convergence and collision in the Neotethyan Realm

Constraining of strain ellipsoid shape from sectional data in the Au bearing shear zone west of Iran

Strain analysis using structural elements and geometry of surfaces of no finite longitudinal strain

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