Tectonostratigraphic synthesis and structural style of the alborz mountain system in Northern Iran

Among the foreland belts of the Andean mountain system, the Eastern Cordillera of Colombia (EC) represents a unique example of an isolated, bi-vergent mountain belt. In contrast, to block tectonics of broken foreland basins, it displays a ductile deformation style which involves two mountain fronts with a structural relief of the order of 10 km. Internal parts of the EC have been shortened by buckling at high and a homogeneously strained basement at deeper structural levels. These deformation patterns likely attest to conditions of a thermally weakened backarc setting. Two opposed scenarios have been postulated for its surface uplift and consequent exhumation: 1) an E-migrating deformation front and the formation of progressively forward breaking faults; and 2) the pop-up of a weak crustal welt enclosed by strong foreland blocks. In this latter setting, a synchronous early formation of marginal mountain fronts and a late-stage surface uplift of a central domain may be anticipated. These two constellations compare, in terms of a contrasting model setup, to a foreland migrating orogenic wedge or a relatively stable, doubly vergent wedge formed above a structural discontinuity or rheologic boundaries that acted as sites for the nucleation of the marginal faults.In this contribution, we opt to examine the &#8220;boundary&#8221; conditions for the development of a doubly vergent wedge formed at the tip line of a rigid tapering backstop, that simulates a rigid foreland block. With respect to the shape of this backstop, we examine the effects of tip angles less than the angle of internal friction (<30&#176;) and find, that at a low tip angle of 10&#176; the pop-up evolves above a forward-breaking principal kink-band with the synchronous formation of a sequence of conjugate back-kinks that cut into the sand pack, as it is pushed toward the backstop. At a moderate tip angle of 20o the forward-breaking kink-band is slightly steeper than the backstop and gives rise to a frontal fold with an overturned limb. This latter geometrical configuration loosely compares to the structural relations of a structural section through the high plains of Bogot&#225;, where the eastern mountain front defines a strongly deformed antiform, that is juxtaposed against an undeformed margin of the adjacent Guyana shield.

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The significance of switch in convergence direction in the Alborz Mountains, northern Iran: Insights from scaled analogue modeling

Interpretation ◽

10.1190/int-2016-0117.1 ◽

2017 ◽

Vol 5 (1) ◽

pp. SD81-SD98 ◽

Cited By ~ 1

Author(s):

Majid Shahpasandzadeh ◽

Hemin Koyi ◽

Faramarz Nilfouroushan

Keyword(s):

Active Tectonics ◽

Deformation Pattern ◽

Eurasian Plate ◽

The South ◽

South Caspian Basin ◽

Northern Iran ◽

The North ◽

Structural Style ◽

Analogue Models ◽

North Of Iran

The switch in direction of convergence between Central Iran and the Eurasian Plate is believed to have a significant impact on the structural style in the Alborz Mountains, in the north of Iran. To understand the deformation pattern and investigate the influence of the South Caspian Basin kinematics since the middle Miocene on the structural styles and active tectonics of the Alborz Mountains, a series of scaled analogue models were prepared, in which passively layered loose sand simulating the sedimentary units were subjected to orthogonal and subsequently oblique shortening by a rigid indenter. Model results indicate that during the shortening, an arcuate-shaped foreland-vergent imbricate stack forms in front of the indenter. The orthogonal shortening is characterized by a prevailing right-lateral and left-lateral oblique-slip motion in the east and west of the model, respectively. This shift in kinematics contradicts the proposed preneotectonic (orthogonal) model of the Alborz. However, during oblique shortening, model results show that deformation is mainly accommodated by left-lateral transpression within the sand wedge and internal deformation. Oblique shortening is consistently accommodated by continued left-lateral motion on the west-northwest-trending oblique thrusts, whereas the east–west-trending thrusts and the preexisting east-northeast-trending right-lateral oblique thrusts reactivate as left-lateral oblique faults. Precise monitoring of the model surface also illustrates partitioning of shortening into the foreland-vergent left-lateral thrusting in the south and hinterland-vergent back thrusting in the north. These model results are generally consistent with field observations and GPS data of structure and kinematics of the Alborz Mountains.

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Eremias papenfussi sp. nov., a new lacertid lizard (Sauria: Lacertidae) from Tehran Province, Iran

Zootaxa ◽

10.11646/zootaxa.3114.1.6 ◽

2011 ◽

Vol 3114 (1) ◽

pp. 57 ◽

Cited By ~ 2

Author(s):

OMID MOZAFFARI ◽

FARAHAM AHMADZADEH ◽

JAMES F. PARHAM

Keyword(s):

New Species ◽

Rocky Mountain ◽

Color Pattern ◽

Mountain Range ◽

Northern Iran ◽

Lacertid Lizard ◽

Alborz Mountain ◽

Tehran Province ◽

A New Species

We describe a new species of Eremias lacertid from the Alborz Mountain range in northern Iran (Tehran Province). Eremias papenfussi n. sp. is part of the Eremias subgenus (or morphotype) by virtue of lacking lateral fringes on the fourth toe and color pattern. It can be further differentiated from previously described species assigned to this morphotype by the absence of distinctly keeled upper caudal scales, gular scales that do not extend to the second inframaxiallary scales, color pattern, and scale counts. Eremias papenfussi is found on rocky mountain slopes of the Alborz where it is presumed to have a much broader distribution than demonstrated by the available specimens. Of the 15 species of Eremias known from Iran, E. papenfussi is the fifth species known to inhabit rocky mountain slopes along with E. strauchi, E. lalezharica, E. montanus and E. novo.

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Lithofacies, architectural elements and tectonic provenance of the siliciclastic rocks of the Lower Permian Dorud Formation in the Alborz Mountain Range, Northern Iran

Journal of African Earth Sciences ◽

10.1016/j.jafrearsci.2015.06.003 ◽

2015 ◽

Vol 109 ◽

pp. 211-223 ◽

Cited By ~ 2

Author(s):

Mojtaba Javidan ◽

Hosseinali Mokhtarpour ◽

Mohammad Sahraeyan ◽

Hojatollah Kheyrandish

Keyword(s):

Lower Permian ◽

Mountain Range ◽

Northern Iran ◽

Architectural Elements ◽

Alborz Mountain ◽

Siliciclastic Rocks

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Diagenetic evolution of the upper Devonian phosphorites, Alborz Mountain Range, northern Iran

Sedimentary Geology ◽

10.1016/j.sedgeo.2018.08.001 ◽

2018 ◽

Vol 376 ◽

pp. 90-112 ◽

Cited By ~ 5

Author(s):

Walid Salama ◽

Zeinab Khirekesh ◽

Arash Amini ◽

Behnam Shafiei Bafti

Keyword(s):

Upper Devonian ◽

Mountain Range ◽

Northern Iran ◽

Alborz Mountain ◽

Diagenetic Evolution

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Epidemiological distribution of rodents as potent reservoirs for infectious diseases in the provinces of Mazandaran, Gilan and Golestan, northern Iran

Infectious Disease Reports ◽

10.4081/idr.2017.6900 ◽

2017 ◽

Vol 9 (2) ◽

Cited By ~ 2

Author(s):

Behzad Esfandiari ◽

Hossein Nahrevanian ◽

Mohammad Reza Pourshafie ◽

Mohammad Mehdi Gouya ◽

Pejvak Khaki ◽

...

Keyword(s):

Statistical Analysis ◽

Infectious Diseases ◽

Economic Losses ◽

Northern Iran ◽

Key Characteristics ◽

Alborz Mountain ◽

Micro Organisms ◽

Geographical Locations ◽

Distribution Frequency ◽

Ecological Differences

Rodents are mammals that comprise more than 2000 species and approximately 30 families. There are many morphological and ecological differences among them as variations in their shape, size, weight and habitat. In addition to significant economic losses, rodents have a major role in the dissemination of infectious diseases caused by viruses, bacteria, parasites or other micro-organisms. Rodents are important reservoirs of diseases which have been observed in many cities of Iran provinces especially along Caspian Sea border to Alborz Mountain. The aim of this study is to assess the geographical distribution of rodents in three provinces of northern part of Iran as reservoir of potential endemic infectious diseases. Rodents in 10 major parts of each of the three provinces of Mazandaran, Gilan and Golestan, northern Iran were collected and a total of 404 rodents were trapped alive. They were determined by the key characteristics such as gender, genus, species, different locations and topological situation. Statistical analysis was performed to characterize the study sample and to correlate all variables and parameters. The distribution frequencies of three, five and six genera of rodents were identified in Mazandaran, Gilan and Golestan provinces respectively. The overall distribution frequency of eight genera of rodents in the three provinces were identified as Rattus (R.) norvegicus (67.3%), R. rattus (13.6%), Apodemus sylvaticus (13.9%), Arvicola (1%), Mus musculus (0.3%), Nesokia indica (2.5%), Cricetulus migrates (0.7%) and Rhombomys opimus (0.7%). The results of this study determined the geographic distribution of the rodents in the three northern provinces of Iran. It is indicated the association of various distribution and diversity of rodents with provincial location. The overall distribution frequency of eight genera of rodents was recognized in the above three provinces geographical locations. This study confirms epidemiological distribution of various rodents as potent reservoirs for infectious diseases, such as leptospirosis, salmonellosis, tularemia, leishmaniasis, etc. in the three provinces.

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Mineral chemistry and thermo-barometry of intrusives from northern side of Shahroud river around Zardkuh in Guilan province (northern Iran)

Nexo Revista Científica ◽

10.5377/nexo.v33i02.10792 ◽

2020 ◽

Vol 33 (02) ◽

pp. 556-578

Author(s):

Mojtaba Bahajrouy ◽

Saeed Taki ◽

Alireza Ganji

Keyword(s):

Tectonic Setting ◽

Volcanic Rocks ◽

Mineralogical Composition ◽

Mineral Chemistry ◽

Mountain Range ◽

Olivine Gabbro ◽

Northern Iran ◽

Exposed Rock ◽

Northern Side ◽

Alborz Mountain

The study area is located in northern Iran and is part of the Alborz mountain range. The exposed rock units in the study area are mostly Eocene volcanic rocks with some Oligomiocene intrusive masses included and locally Paleocene, Jurassic, Permian and Carboniferous sedimentary outcrops. The intrusive rocks of the study area are mostly gabbro and olivine gabbro in terms of mineralogical composition, but intermediate types such as porphyry monzonite are also rarely seen. Based on the results of microprobe analysis, pyroxenes have augite and diopside compositions, orthopyroxenes are hypersthenes, biotites have magnesium biotite and phlogopite compositions, olivines have hyalosiderite compositions and amphiboles are pargasite and ferropargasite compositionally. The results of temperature and pressure evaluation indicate a temperature range of 650 to 1200 ° C and pressure range >2-5 KB. Based on the chemistry of clinopyroxene mineral of the mentioned intrusions, magma that made these intrusions is of the sub-alkaline type and is formed in a volcanic arc tectonic setting.

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Botanical diversity of Hyrcanian forests; a case study of a transect in the Kheyrud protected lowland mountain forests in northern Iran

Phytotaxa ◽

10.11646/phytotaxa.7.1.1 ◽

2013 ◽

Vol 7 (1) ◽

pp. 1-18 ◽

Cited By ~ 14

Author(s):

S. Siadati ◽

H. Moradi ◽

F. Attar ◽

V. Etemad ◽

B. Hamzeh'ee ◽

...

Keyword(s):

Extended Period ◽

Life Forms ◽

Mountain Range ◽

Forest Patches ◽

Northern Iran ◽

Alborz Mountain ◽

Extended Area ◽

Floristic Data ◽

The University

Hyrcanian or Caspian forests follow a profile along the northern slopes of the Alborz mountain range, located in the provinces of Gilan, Mazandaran and Golestan in northern Iran. The area is approximately 800 km long and 110 km wide and a covers ca 1.84 million hectare. There are few protected forest patches across this extended area in northern Iran, but Kheyrud forest is one of these reserves, which has been under the direct supervision and protection by the University of Tehran for an extended period of time. The area includes three elevational classes, lowland (50-500 m), submountain (501-1000 m) and mountain (1001-2200 m). It lies seven km east of Now-Shahr and covers an area of 10,000 hectare. Based on floristic collecting during spring, summer and autumn of 2008 and 2009, three plots were made, each with a 100 m elevational interval. Floristic data were collected in 234 plots. Data related to elevation, slope and direction were also noted. A total of 295 plant taxa were encountered, out of which 29 taxa (10%) are endemic to Iran and 16 taxa (5.5%) are only found in the Hyrcanian provinces. Classification based on life form indicates that geophytes (with 110 taxa, 37.5%) constitute the largest proportion. Chorologically, the largest proportion of the flora is constituted of Euro-Siberian elements (72 taxa, 24.7%). In addition to general assessments, variation of life forms between the study area and other similar areas are discussed. A comparison was made between the floristic data of the three elevational belts. The result of this investigation indicates that the species diversity increases with the increase of elevation. Likewise, the proportion of hemicryptophytes and geophytes are more prominent in the montane belt above 1000 m.

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