Late Cenozoic shortening in the west-central Alborz Mountains, northern Iran, by combined conjugate strike-slip and thin-skinned deformation

Guest, Bernard; Axen, Gary J.; Lam, Patrick S.; Hassanzadeh, Jamshid

doi:10.1130/ges00019.1

Cited by 189 publications

(193 citation statements)

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“…The relationship between the mean vitrinite reflectance and Tmax values of the Shemshak Group and the thickness of the Shemshak Group and overlying sediments in the studied and modelled sections is shown on During the Late Neogene, exhumation of Alborz accompanied with inversion tectonics, the most deeply buried parts of the Shemshak Group were highly uplifted and exposed, whereas marginal parts of the Central-Eastern Alborz were less uplifted (Alavi, 1996;Allen et al, 2003;Zanchi et al, 2006;Guest et al, 2006Guest et al, , 2007. Maximum of subsidence and uplift in the Central-Eastern Alborz occurred along the axis of the Alborz.…”

Section: Discussionmentioning

confidence: 99%

“…The resulting EoCimmerian orogeny formed an E-W mountain belt, the so-called Cimmerides (Sengör, 1990;Sengör et al, 1998). The Alborz Range of Northern Iran itself results from the collision of Arabia with Eurasia during the Neogene which caused uplift, folding and faulting (Stöcklin, 1974;Alavi, 1996;Zanchi et al, 2006;Guest et al, 2006Guest et al, , 2007. The thick siliciclasticdominated Shemshak Group (Upper Triassic to Middle Bajocian), with thicknesses up to 4000 m, is widely distributed in the Alborz (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

Shekarifard

Baudin²,

Seyed–Emami

et al. 2011

Geol. Mag.

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Organic petrography and geochemical analyses have been carried out on shales, carbonaceous shales and coals of the Shemshak Group (Upper Triassic–Middle Jurassic) from 15 localities along the Alborz Range of Northern Iran. Thermal maturity of organic matter (OM) has been investigated using vitrinite reflectance, Rock-Eval pyrolysis and elemental analysis of kerogen. Reflectance of autochthonous vitrinite varies from 0.6 to 2.2% indicating thermally early-mature to over-mature OM in the Shemshak Group, in agreement with other maturity parameters used. The shales of the Shemshak Group are characterized by poor to high residual organic carbon contents (0.13 to 5.84%) and the presence of hydrogen-depleted OM, predominantly as a consequence of oxidation of OM at the time of deposition and the hydrogen loss during petroleum generation. According to light-reflected microscopy results, vitrinite/vitrinite-like macerals are dominant in the kerogen concentrates from the shaly facies. The coals and carbonaceous shales of the Shemshak Group show a wide range in organic carbon concentration (3.5 to 88.6%) and composition (inertinite- and vitrinite-rich types), and thereby different petroleum potentials. Thermal modelling results suggest that low to moderate palaeo-heat flow, ranging from 47 to 79 mW m−2 (57 mW m−2 on average), affected the Central-Eastern Alborz basin during Tertiary time, the time of maximum burial of the Shemshak Group. The maximum temperature that induced OM maturation of the Shemshak Group seems to be related to its deep burial rather than to a very strong heat flow related to an uppermost Triassic–Liassic rifting. The interval of petroleum generation in the most deeply buried part of the Shemshak Group (i.e. Tazareh section) corresponds to Middle Jurassic–Early Cretaceous times. Exhumation of the Alborz Range during Late Neogene time, especially along the axis of the Central-Eastern Alborz, where maximum vitrinite reflectance values are recorded, probably destroyed possible petroleum accumulations. However, on the northern flank of the Central-Eastern Alborz, preservation of petroleum accumulations may be expected. The northern part of the basin therefore seems the best target for petroleum exploration.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

Shekarifard

Baudin²,

Seyed–Emami

et al. 2011

Geol. Mag.

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“…Shortening across the Alborz is estimated to range between 30 and 56 km Guest et al 2006a) and probably began between ∼ 17 Ma, if one considers the increase in accumulation rates (Ballato et al 2008(Ballato et al , 2011, and 12 Ma ago (Guest et al 2006b) in the Western Alborz or 6-4 Ma in the Central Alborz (Axen et al 2001) if rapid exhumation is taken into account (Fig. 1b).…”

Section: C Timing and Amount Of Shortening In The Alborz And The Cmentioning

confidence: 99%

Timing of uplift in the Zagros belt/Iranian plateau and accommodation of late Cenozoic Arabia–Eurasia convergence

Mouthereau¹

2011

Geol. Mag.

145

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-The motion of Arabia was stable with respect to Eurasia over the past 22 Ma. Deformation and exhumation in the Zagros is seen to initiate at the same time as argued by new detrital thermochronologic constraints and increasing accumulation rates in synorogenic sediments. A recent magnetostratigraphic dating of the Bakhtyari conglomerates in the northern Fars region of the Zagros further suggests that shortening and uplift in the Zagros Folded Belt accelerated after 12.4 Ma. Available temporal constraints from surrounding collision belts indicate that shortening and uplift focused in regions bordering the Iranian plateau to the south between 15 and 5 Ma. As boundary velocity was kept constant this requires concomitant decreasing strain rates in the Iranian plateau. Slab detachment has been proposed to explain the observed changes as well as mantle delamination, but the insignificant change in the Arabian slab motion and lack of unambiguous constraints make both hypotheses difficult to account for. It is proposed based on a review of shortening estimates provided throughout the Arabia-Eurasia collision that the total 440 km of convergence predicted by geodesy and plate reconstruction over the past 22 Ma can be accounted for by distributed shortening. I suggest that the topography and expansion of the Iranian plateau over Late Miocene-Pliocene time can be reproduced by the progressive thickening of the originally thin Iranian continental lithosphere presumably thermally weakened during the Eocene extensional and magmatic event.

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“…The evolution of the Alborz belt mainly occurred in the Cenozoic (Rezaeian et al, 2012). Opening and subsequent closure of the Neotethys along the Zagros Mountains and opening of the Red Sea had important effects on the structural evolution of the Alborz belt (Axen et al, 2001;Guest et al, 2006;Omrani et al, 2013). Collision of the Gondwana-derived blocks with Eurasia occurred in the Late Triassic, resulting in the Eo-Cimmerian deformation in North Iran, followed by a strong but poorly known Neo-Cimmerian compression event in Middle-Late Jurassic times that mainly affected Central Iran ).…”

Section: Geological Background and Local Geologymentioning

confidence: 99%

Whole Rock Geochemistry and Tectonic Setting of Jurassic Aged Lisar Granite, Talesh Mountains, North Iran

Seghinsara¹,

Karizaki²,

Moazzen³

et al. 2017

Bulletin of the Mineral Research and Exploration

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The Late Jurassic aged Lisar granite in North Iran is in tectonic contact of the form of thrust and strike slip faults with Upper Cretaceous sandy limestone and is covered by Paleogene polygenetic conglomerate in the Talesh Mountain at the western continuation of the Alborz range. The rock samples of the granite are pink coloured and coarse-gained with K-feldspar, quartz, plagioclase, biotite and amphibole. The Lisar granite is more likely emplaced in an extensional environment indicated with numerous space fi lling silica-rich aplitic veins in the rocks. The granite samples are moderately altered and feldspars are changed to sericite and clay minerals and biotite is partially converted to chlorite. The Lisar granite has derived from a high K magma and is A-type in nature, belonging to A 2 subgroup. The rock samples of granite are characterized by distinct negative Eu anomaly and a decrease from LREE to HREE contents. The parental melts of the granite were generated from partial melting of a lower continental crustal source with possible contribution from the mantle materials. The Lisar granite represents Cimmerian post-collision magmatism in north Iran following closure of Palaeotethys Ocean and subsequent collision. IntroductionPalaeomagnetic studies show that Iran was a part of Gondwana up to Early Carboniferous (Alavi, 1991;Majidi, 1991;Mirnejad et al., 2013; Shafaii Moghdam et al., 2015), Gorgan schists (Ghavidel et al., 2007;Delaloy et al., 1981), metamorphic rocks of the Gasht and Masuleh area (Clark et al., 1975) and Shanderman eclogites (Zanchetta et al., 2009;Omrani et al., 2013). The Palaeotethys suture can be traced to the east to Afghanistan and China and towards the west into Turkey . The Palaeotethys ocean closed 225 Ma ago which followed by uplifting of the Turan plate and emplacement of allochtonous nappes on the Iranian plate (Stampfl i, 1993). Magmatic activities, especially granitoid magmatism, related to the Palaeotethys subduction are well documented along the suture in China. The magmatic arc at Yunnan area (southwestern Yunnan, China), with basaltic-andesitic to granodiorite composition has an age of 292-282 Ma (Hennig et al., 2009). I-type and S-type granitoids of Hindu Kush in Afghanistan have ages of 210, 112 and 193 Ma, respectively (Debon et al., 1987). These granites with roughly Triassic age are traced westward into east of Iran, where the Binalud granites and granodiorites, dated 256 to 211 Ma (Majidi, 1978;Berberian and Berberian, 1981), are intruded into * Corresponding author: Mohssen MOAZZEN moazzen@tabrizu.ac.ir

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Late Cenozoic shortening in the west-central Alborz Mountains, northern Iran, by combined conjugate strike-slip and thin-skinned deformation

Cited by 189 publications

References 16 publications

Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

Timing of uplift in the Zagros belt/Iranian plateau and accommodation of late Cenozoic Arabia–Eurasia convergence

Whole Rock Geochemistry and Tectonic Setting of Jurassic Aged Lisar Granite, Talesh Mountains, North Iran

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