Zones Of Iran Research Articles

Impacts of the Belt and Roads Initiative on Sustainability: Local Approaches to Spatial Restructuring in the Aras Special Economic Zones

Spatial restructuring and regional economic development are closely associated with sustainability. Despite the considerable literature on urbanization’s impact on sustainable economic development and urban expansion, few studies have explored how FDI-led spatial restructuring affects the sustainability from a local people perspective. To fill this gap, in-depth interviews were conducted with 516 residents of Aras special economic zones in Iran to assess the impacts and responses to economic shifts and spatial restructuring resulting from the Belt and Road Initiative since 2013. Using the DPSIR framework and sustainability index as an evaluation tool, we assessed the degree of sustainability and viable uplift at the regional level. The Genetic Algorithm (GA) was also utilized to determine optimal values based on local approaches. Results indicate that regional heterogeneity, excessive state pressure, and development imbalances impact the study area. The findings enrich the theory of sustainability and can guide the formulation of spatial restructuring, decision-making, and policies at different stages of regional development. In addition to financial progress, people-centered development planning using local approaches should be a component of the development of special economic zones.

Permian to recent tectonic evolution of the Palaeotethys suture zone in NE Iran

Permian to recent tectonic evolution of the Palaeotethys suture zone in NE Iran

Paleozoic Tensional Intraplate Magmatism and Mantle Evolution in Central Iran Zone: Geochemistry, Nd-Sr Isotope Data of Lamprophyres

Paleozoic Tensional Intraplate Magmatism and Mantle Evolution in Central Iran Zone: Geochemistry, Nd-Sr Isotope Data of Lamprophyres

The Middle Jurassic Cheshmeh-Ghasaban High-Mg gabbro (Hamedan, NW Iran): A plume-influenced intracontinental rifting event?

The Jurassic mafic to felsic magmatism affecting the older Ediacaran-to-Cambrian basement of the Sanandaj-Sirjan Zone of Iran has been traditionally interpreted as the product of arc and/or back-arc magmatism related to the early stages of Neo-Tethys subduction beneath Iran in the early Jurassic. Recent works and new compositional and geochronological data have started challenging this commonly accepted model in favor of scenarios involving continental rifting, mantle plume activity, and/or passive margin formation. In the Hamedan area of the central sector of the Sanandaj-Sirjan Zone, the Jurassic Cheshmeh-Ghasaban gabbro (ca. 165 Ma) is a key formation to better understand the tectono-magmatic framework of the whole area. Our new data, combined with the existing literature, suggest a transitional to alkaline OIB-like compositional character for this gabbro similar to the nearby but slightly younger (ca. 145 Ma) Panjeh and Ghalaylan basaltic complexes (in the Songhor-Ghorveh area). When integrated with the existing geochemical data of Jurassic mafic rocks from the central Sanandaj-Sirjan Zone, our results point to a scenario of intracontinental rifting, possibly involving the upwelling old metasomatized (by Proto-Tethys subduction?) mantle or mantle-plume activity.

The application of vertical electrical sounding in geomechanical recognition of host rock mass of anomaly III of Narigan deposit, Bafgh region, Central Iran zone

روش الکتریکی به عنوان یک بررسی ژئوفیزیکی می‌تواند پارامترهای زمین‌شناسی شامل خردشدگی، شاخص دگرسانی توده سنگ، درصد اشباع، کیفیت آب زیرزمینی و . . . را به خوبی نمایش دهد. این پارامترها نقش مهمی در طبقه‌بندی مهندسی توده سنگ از طریق تأثیر بر دو شاخص کیفیت توده سنگ (RQD) و شاخص مقاومت زمین‌شناسی (GSI)، کانه‌زایی عناصر و نیز نحوه حفاری دارند. در این مقاله با استفاده از روش سونداژ الکتریکی قائم در لایه‌های زیرسطحی به بررسی تعیین این پارامترها و متعاقباً دو شاخص مذکور در توده‌سنگ‌های آذرآواری آنومالی III کانسار ناریگان پرداخته شده است. نتایج نشان می دهد که مقاومت ویژه الکتریکی تفسیر شده (با استفاده از نرم‌­افزار win2IPI) ارتباط قابل قبولی با میزان شاخص دگرسانی و تا حدی GSI در توده سنگ دارد. با این حال تعیین دقیق GSI و هم‌­چنین RQD با استفاده از این روش ژئوفیزیکی از اعتماد بالایی برخوردار نیست. به بیان ساده­تر با استفاده از یک رابطه ریاضی نمی‌­توان با مقاومت ویژه الکتریکی میزان GSI و شاخص آلتراسیون را تخمین زد.

Fluid Inclusions and REE Geochemistry of White and Purple Fluorite: Implications for Physico-Chemical Conditions of Mineralization; an Example from the Pinavand F Deposit, Central Iran

The Pinavand fluorite deposit is hosted by lower Cretaceous carbonate rocks in the structural-geological transitional zone of Central Iran. The purple and white fluorite occur, respectively, as early replacement masses and late cross-cutting veins. Both fluorites have different and distinct physicochemical characteristics. The purple fluorite has higher homogenization temperatures of fluid inclusions (170–260 °C) and lower ∑REE (1.6 ppm) and Y (1.3 ppm) than the white variety (90–150 °C, 11.12 ppm, and 21.3 ppm, respectively). All fluorite samples show positive Y anomalies (Y/Y*) in the range of 1.15–3.5. The average values of La/Ho in the purple and white fluorites are 23.1 and 3.4, respectively. The purple fluorite samples have lower Y/Ho values (an average of 63.45) than the white fluorite samples (an average of 87.64). The Tb/Ca ratio in the Pinavand fluorites ranges between 0.0000000348 and 0.00000105, and the Tb/La ratio varies between 0.01 and 0.4; these values suggest that both fluorite types are “hydrothermal” in origin. The purple fluorites have a lower Sr and a negative Eu anomaly. These differences in concentrations and ratios of various REE suggest that the physico–chemical conditions of mineralization changed during fluorite deposition at the Pinavand. These changes correspond to an increase in oxygen fugacity and pH, which occurred during white fluorite mineralization at lower temperatures. The δ34S values of the Pinavand barite samples (an average of 23.25‰) are similar to those of seawater sulfate in the upper Proterozoic. The δ34S values of galena range from −0.2‰ to −3.7‰, compatible with bacterial sulfate reduction (BSR). These features are similar to those in the hydrothermal and magmatic deposits.

Understanding the magma-crust interaction: the role of the northern Gondwana margin in the genesis and evolution of the Jurassic Alvand plutonic complex (Sanandaj-Sirjan Zone, NW Iran)

This work investigates the petrogenesis of the main magmatic rocks of the Jurassic Alvand plutonic complex, located in the northern sector of the Sanandaj-Sirjan Zone of Iran. The Alvand complex is made up of a wide range of rocks spanning gabbro to leucogranites, containing a diversified range of enclaves, from mafic-to felsic- and surmicaceous-type. Here we present new textural characterization together with mineral, whole rock and Sr–Nd isotope chemistry of the main magmatic lithotypes. We integrated this new data with the available ones to understand the petrogenesis of the Alvand magmas and their interaction with the Ediacaran-Cambrian crystalline basement. A legacy of the Peri-Gondwanan crust is evident in Alvand felsic rocks. The whole rock chemistry, the Sr–Nd isotope ratios and assimilation-fractional crystallization numerical models indicate their genesis partly through differentiation via fractional crystallization from the coeval Alvand gabbros coupled with a concurrent and significative mass-addition of material from the Cadomian basement. At a wider scale, this work also provides new insights into the understanding the role of the continental crust in the buildup of transcrustal magmatic systems and therefore to a better comprehension of crust growth process driven by intense magma-crust interaction events.

Lithostratigraphy, lithofacies and deposition conditions of the late Olenekian-middle Anisian Alam Formation in the Nakhlak area, central Iran

The present study aims to investigate petrography characteristics and sedimental environments of upper Olenekian–middle Anisian deposits of Nakhlak group in the sedimentary-structural zone of central Iran. To this end, a section of these deposits with a thickness of 720 meters was first selected, and 190 samples were taken from this section for preparing thin sections. Also, quantitative and qualitative laboratory tests were performed and 25 samples of sandstone were selected for point counter analysis. The results indicated that the major deposits of this formation are related to siliciclastic, carbonate, and pyroclastic types, which are in the form of two facies associations. The facies association A at the bottom of the studied section with the thickness of 90 meters has a periodicity of clastic, carbonate, and pyroclastic facies. The clastic facies of this association consists of fine-grained sandstone. In addition, the carbonate facies in association A are characterized by two microfacies consisting of intraclast oolitic grainstone and oolitic grainstone. Further, tuffite is the only pyroclastic facies related to association A, which has a laminate structure, cross-bedding lamination, herringbone bedding, and upward-thinning and thickening cycles. The facies association, B which is deposited later, is more in the middle and top part of the section. The facies association B is 660 meters thick and has a periodicity of clastic and limestone facies. Clastic facies of this association includes four lithofacies such as conglomerate, pebble coarse-grained sandstone, medium-grained sandstone to thin layer siltstone and shale. The carbonate facies consists of four microfacies such as sandy intraclastic wackestone and mudstone. Furthermore, slumping structures, cross bedding, turbulence, boudinage structure, and convolute of sediments, along with the effects of erosional channels are observed in facies B. Field and laboratory studies conducted on this succession indicate the structure of facies association A was deposited in a mixed siliciclastic carbonate ramp. Finally, submarine canyons and submarine fan environments were left by increasing the depth of the facies association B in the deep part of sea and turbidity systems.

Evaluating IMERG Precision: Comparative Study of Daily and Six-Hourly Scales in Diverse Climate Zones of Iran

Evaluating IMERG Precision: Comparative Study of Daily and Six-Hourly Scales in Diverse Climate Zones of Iran

The Generation of Eocene Mafic Dike Swarms During the Exhumation of a Core Complex, Biarjmand Area, NE Iran

Abstract Several swarms of parallel E–W dikes cuts late Neoproterozoic- to early Paleozoic (540 Ma) basement in the Biarjmand area, NE Iran. The microgabbroic to doleritic dike are several hundred meters long and 0.5 to 3 meters wide. U–Pb dating of their zircon grains yields a crystallization age of 46.0 ± 7.1 Ma for the dike swarms. The dikes have SiO2 contents of 46.0–49.3 wt%, and Fe2O3 contents of 9.80–14.8 wt% with variable MgO (4.92–9.16 wt%), TiO2 (1.47–2.65 wt%), and K2O contents (0.33–1.13 wt%). The dikes have low contents of high field strength elements (HFSEs), and have some similarities to transitional mid-ocean ridge basalts (T-MORB) based on their chemical composition. Positive ${\varepsilon}_{Nd}(t)$ values of +5.2 to +6.0 for the dike samples imply that the basaltic magma was generated from depleted lithospheric mantle. After the closure of the Sabzevar ocean and obduction of the large mantle peridotite body over the continental crust in the late Cretaceous-Paleocene, the gravitational instability in the central Iran/Eurasia plate collision zone triggered exhumation of old basement coeval with injection of the mafic magma. During exhumation, mylonitic deformation with brittle-ductile structures affected the basement metagranite and the host rocks. The metagranite and dike swarms cut the Cretaceous Sabzevar ophiolite, and the disparting of ophiolite members probably occurred during basement exhumation in the Cenozoic. The similar ages of the mafic dike swarms and other Eocene magmatic rocks of the Urumiah (Urmia) Dokhtar magmatic arc (UDMA), western Iran, is consistent with a rapid extensional regime over the Sabzevar suture zone on an earlier collision zone in NE Iran. This process provided a suitable setting for the exhumation of the old basement, the emplacement of the parallel dike swarm, and the development of shallow basins in this area.

Underestimated diversity in high elevations of a global biodiversity hotspot: two new endemic species of Aethionema (Brassicaceae) from the alpine zone of Iran.

Although the mountains in South-West Asia are a global biodiversity hotspot, our understanding of their biodiversity, especially in the commonly remote alpine and subnival zones, is still limited. This is well exemplified here by Aethionema umbellatum (Brassicaceae), a species considered to have a wide yet disjoint distribution in the Zagros and Yazd-Kerman mountains of western and central Iran. Morphological and molecular phylogenetic data (based on plastid trnL-trnF and nuclear ITS sequences) show that A. umbellatum is restricted to a single mountain range in southwestern Iran (Dena Mts., southern Zagros), whereas populations from central Iran (Yazd-Kerman and central Zagros) and from western Iran (central Zagros) belong to species new to science, A. alpinum and A. zagricum, respectively. Both new species are phylogenetically and morphologically close to A. umbellatum, with which they share unilocular fruits and one-seeded locules. However, they are easily distinguishable by leaf shape, petal size, and fruit characters. This study confirms that the alpine flora of the Irano-Anatolian region is still poorly known. As the proportion of rare and local endemic species in alpine habitats is high, these habitats are of prime interest for conservation efforts.

Iranian wetland inventory map at a spatial resolution of 10 m using Sentinel-1 and Sentinel-2 data on the Google Earth Engine cloud computing platform

Detailed wetland inventories and information about the spatial arrangement and the extent of wetland types across the Earth's surface are crucially important for resource assessment and sustainable management. In addition, it is crucial to update these inventories due to the highly dynamic characteristics of the wetlands. Remote sensing technologies capturing high-resolution and multi-temporal views of landscapes are incredibly beneficial in wetland mapping compared to traditional methods. Taking advantage of the Google Earth Engine's computational power and multi-source earth observation data from Sentinel-1 multi-spectral sensor and Sentinel-2 radar, we generated a 10m nationwide wetlands inventory map for Iran. The whole country is mapped using an object-based image processing framework, containing SNIC superpixel segmentation and a Random Forest classifier that was performed for four different ecological zones of Iran separately. Reference data was provided by different sources and through both field and office-based methods. Almost 70% of this data was used for the training stage and the other 30% for evaluation. The whole map overall accuracy was 96.39% and the producer's accuracy for wetland classes ranged from nearly 65 to 99%. It is estimated that 22,384 km2 of Iran are covered with water bodies and wetland classes, and emergent and shrub-dominated are the most common wetland classes in Iran. Considering the water crisis that has been started in Iran, the resulting ever-demanding map of Iranian wetland sites offers remarkable information about wetland boundaries and spatial distribution of wetland species, and therefore it is helpful for both governmental and commercial sectors.

Geochemistry and Sr–Nd isotopic characteristics of ferroan-magnesian metaluminous granites of the NW Sanandaj–Sirjan zone, Iran: granite formation in a compressional–extensional setting during Late Jurassic time

AbstractThe Almogholagh–Dehgolan region is in the North Sanandaj–Sirjan zone of NW Iran. The granites of the region are metaluminous and display geochemical and textural characteristics of transitional granites between ferroan (A-type) and I-type granites. In geotectonic discrimination diagrams, the Almogholagh–Dehgolan granites plot mainly in the fields of within-plate granites and volcanic arc granites. With the exception of the Qalaylan granites, parts of other granites resemble A2-type granites. Granites of the Qalaylan intrusive body have petrographic and geochemical features close to I-type granites and are not A-type. Primary mantle and chondrite-normalized spider diagrams show enrichments in light rare earth elements relative to heavy rare earth elements. For an age of 150 Ma, the initial87Sr/86Sr and143Nd/144Nd ratios vary from 0.702769 to 0.706545 and from 0.512431 to 0.512558, respectively. Epsilon Nd values vary in a relatively limited range between −0.3 and +2.2, which corresponds to a mixed mantle–crustal source. On the basis of new geochemical and isotopic data, we suggest a geodynamic model involving partial melting of lower crustal rocks with the contribution of mantle magmas in a weakly extensional tectonic setting for the generation of the A-type granites of the region. The occurrence of ferroan (A-type) granites in this region of the Sanandaj–Sirjan zone indicates the existence of a partly extensional tectonic environment in a mainly compressional subduction-related regime in Late Jurassic time.

Machine Learning-Based Assessment of Watershed Morphometry in Makran

This study proposes an artificial intelligence approach to assess watershed morphometry in the Makran subduction zones of South Iran and Pakistan. The approach integrates machine learning algorithms, including artificial neural networks (ANN), support vector regression (SVR), and multivariate linear regression (MLR), on a single platform. The study area was analyzed by extracting watersheds from a Digital Elevation Model (DEM) and calculating eight morphometric indices. The morphometric parameters were normalized using fuzzy membership functions to improve accuracy. The performance of the machine learning algorithms is evaluated by mean squared error (MSE), mean absolute error (MAE), and correlation coefficient (R2) between the output of the method and the actual dataset. The ANN model demonstrated high accuracy with an R2 value of 0.974, MSE of 4.14 × 10−6, and MAE of 0.0015. The results of the machine learning algorithms were compared to the tectonic characteristics of the area, indicating the potential for utilizing the ANN algorithm in similar investigations. This approach offers a novel way to assess watershed morphometry using ML techniques, which may have advantages over other approaches.

Prediction of tunnel squeezing in soft sedimentary rocks by geoelectrical data

Squeezing is time-dependent deformation that can cause technical difficulties and financial consequences in underground structures. This study employs electrical resistivity data to predict squeezing intensity along the Beheshtabad tunnel in the Sanandaj–Sirjan zone in Iran. For comparison analysis, a semi-empirical approach was correlated with numerical modeling to predict tunnel squeezing at the design stage. The squeezing intensity obtained for the Beheshtabad tunnel was then compared with the instability observations along the Golab tunnel excavated in sedimentary rocks of the same zone. We developed a relationship between electrical resistivity and strains and provided a new strain-based squeezing classification system. The calibrated electrical data produced more accurate results for predicting tunnel squeezing than the conventional methods. The results show that rock type, joint properties, and water saturation impact squeezing.

Assessment of RXD Algorithm Capability for Gas Flaring Detection through OLI-SWIR Channels

The environment, the climate and human health are largely exposed to gas flaring (GF) effects, releasing significant dangerous gases into the atmosphere. In the last few decades, remote sensing technology has received great attention in gas flaring investigation. The Pars Special Economic Energy Zone (PSEEZ), located in the south of Iran, hosts many natural oil/gas processing plants and petrochemical industries, making this area one of the most air-polluted zones of Iran. The object of this research is to detect GF-related thermal anomalies in the PSEEZ by applying, for the first time, the Reed-Xiaoli Detector (RXD), distinguished as the benchmark algorithm for spectral anomaly detection. The RXD performances in this research field have been tested and verified using the shortwave infrared (SWIR) bands of OLI-Landsat 8 (L8), acquired in 2018 and 2019 on the study area. Preliminary results of this automatic unsupervised learning algorithm demonstrated an exciting potential of RXD for GF anomaly detection on a monthly scale (75% success rate), with peaks in the months of January and February 2018 (86%) and December 2019 (84%). The lowest detection was recorded in October 2019 (48%). Regarding the spatial distribution of GF anomalies, a qualitatively analysis demonstrated the RXD capability in mapping the areas affected by gas flaring, with some limitations (i.e., false positives) due to possible solar radiation contribution. Further analyses will be dedicated to recalibrate the algorithm to increase its reliability, also coupling L8 and Landsat 9, as well as exploring Sentinel 2 SWIR imagery, to overcome some of the observed RXD drawbacks.

Origin and evolution of the ore-forming fluids in the southern Abbas Abad iron skarn deposit, NE Isfahan, Central Iran: Insights from geology, fluid inclusions, and C[sbnd]O isotopes

The southern Abbas Abad iron skarn deposit is located in the western part of the Central Iran zone, SW edge of the Urumieh˗Dokhtar magmatic arc. The skarn alteration occurred mainly at the contact of the Abbas Abad gabbro and Triassic Nayband Formation. The Triassic Nayband Formation in the southern Abbas Abad area consists of limestone, shale, siltstone, and marl with interlayers of tuff. The Abbas Abad gabbro is calc˗alkaline with adakitic signatures and continental arc setting affinity. Four iron ore bodies occur along the NW˗SE trending normal fault along the southern margin of Abbas Abad gabbro within sedimentary host rocks of the Nayband Formation. Three main paragenetic stages of skarnification and ore deposition have been recognized: i) prograde stage, ii) retrograde stage, and iii) supergene stage. Spinel, garnet, and pyroxene formed during the prograde stage. Epidote, tremolite˗actinolite, calcite and ore minerals, such as magnetite, hematite-I, pyrite, and minor chalcopyrite formed the retrograde stage assemblage. Magnetite is the main economic ore mineral, which is diverse in terms of fabric and texture, including massive, disseminated, needle˗like, blade˗like, prismatic, crustification, and cubes. Stable isotope data from Abbas Abad iron skarn deposit indicated that the interaction of non-magmatic brine (connate) fluids with Triassic carbonate host rocks at high temperature and its mixing with meteoric water has led to changes in the isotopic composition of the mineralizing fluid. Subsequently, garnet and magnetite with relatively high estimated fluid δ18O values (average 12.3 and 14.6 ‰, respectively) formed from this modified fluid. The estimated δ18O values of fluid in equilibrium with calcite decreased as a result of the greater influx of the meteoric water into the hydrothermal system in the late stages of ore formation. Fluid inclusion data from this iron skarn deposit are consistent with minor boiling during the prograde stage, although cooling and dilution seem to be principally responsible for Fe precipitation. The petrogenetic model proposed for the Southern Abbas Abad iron skarn deposit suggests that during the Eocene a gabbroic stock intruded the sedimentary rocks of the Nayband Formation and acted as a heat source for the non-magmatic brine (connate and meteoric) fluids convection cells, then reacted with cooler Triassic carbonate rocks. In this model, leaching of the gabbroic rock provided the iron, whereas carbon came from degassing and dissolution of carbonate rocks during contact metamorphism-metasomatism.

Assessing the changeability of precipitation patterns using multiple remote sensing data and an efficient uncertainty method over different climate regions of Iran

While the rain gauge measurements are unevenly distributed in many world regions, it is necessary to use remote sensing-based precipitation data at high spatial and temporal resolutions. On the other hand, quantifying the uncertainty of precipitation is a vital issue for hydrometeorological applications globally. For this purpose, applying a new fusion framework using high-resolution remote sensing datasets can provide accurate precipitation evaluation against local observations with low uncertainty. This study examines three weighted fusion-based models containing the Ordered-Weighted-Averaged (OWA) family approach based on the ORLIKE method (OWA-ORLIKE) and ORNESS method (OWA-ORNESS) as well as the Entropy-weight (EW) method to combine different remote sensing precipitation products over different climate zones of Iran. In this case, multiple monthly remotely sensed datasets, including ERA5, ERA5-Land, TerraClimate, GPM, PERSIANN-CDR, TRMM, and CHIRPS, are utilized to assess precipitation patterns versus local measurements, which were gathered by Google Earth Engine (GEE) platform. Furthermore, the K-means algorithm is employed to cluster ground-based precipitation stations based on the climate zones category across Iran. Additionally, the Genetic Optimization Algorithm (GOA) is applied to specify optimal values of weights in weighting-based models. The performance of single and combination datasets are evaluated using statistical error metrics, including Pearson correlation coefficient (PCC), root mean square error (RMSE), Kling Gupta efficiency (KGE), and bias. The Thiessen polygon method has been applied to calculate each cluster's mean precipitation to obtain the optimal weights of stations. Finally, as an efficient uncertainty approach, Cross Wavelet Transform (XWT) method has been used for uncertainty assessment of monthly and seasonal precipitation series. Results indicated that the OWA family as the best fusion model had almost the lowest uncertainty values and best statistical error indices compared to the EW model and all single products in different clusters of Iran. As a motivation part of this study, unlike the single sources of remotely sensed data, multiple datasets can apply together in different climate conditions with various features using combination models, which mentioned uncertainty method has clearly revealed this claim.

Significance of Serum Apelin Levels as a Biomarker for Gastric Cancer Diagnosis.

Gastric cancer (GC) is one of the common lethal disease and the most common cancers worldwide and in Iran. North of Iran is known as a common area of gastric cancer and a high-risk zone in Iran. Apelin is a biomolecule that plays roles in various types of cancers. This study was designed to investigate the serum apelin-12 levels in patients with gastric cancer as a predictive marker and affordable noninvasive alternative. In this case-control study, the case group included 42 patients with gastric cancer who were diagnosed by endoscopy and pathological findings. The participants in the case group were compared with the control group including 43 healthy individuals with no history of gastric cancer in their first-degree relatives and visiting the lab for routine tests. Apelin-12 serum level was assessed using ELISA kit. Data were analyzed in SPSS V16.0 applying Fisher's exact test, Mann-Whitney U test, and t-test. Serum apelin-12 in patients with gastric cancer was found to be statistically lower than that in healthy individuals (p< 0.05). There were no significant differences between clinicopathological characteristics and apelin-12 expression. The median survival time in experimental and control groups was 16.0 months. In the current study, serum levels of apelin were significantly different between cases and controls.

Migration of the Palaeozoic magmatic front from Zagros to Alborz mountains with progressive closure of the Palaeo-Tethys Ocean; Insights from Zagros detrital zircon U[sbnd]Pb age and Hf isotopic composition

The northwest-southeast-trending Zagros Fold-and Thrust Belt in south Iran resulted from the late Oligocene to the early Miocene collision of the Arabian and Central Iran blocks. The Zagros Palaeozoic basin holds the key to reveal the tectonic setting of the earlier stages in the development of the Tethyan realm. We aim to document the Palaeozoic tectonic environment of the Zagros Basin and provide critical constraints on the progressive closure of the Palaeo-Tethys. This work presents a combined detrital zircon UPb age and Hf isotopic composition from the Zagros and Alborz basins in an attempt to identify and date major geologic events along the southern margin of the Palaeo-Tethys and reconstruct the regional tectonic history of the northern margin of Gondwana-Land during the Ediacaran-early Palaeozoic interval. Detrital zircons UPb age and Hf-isotope ratio from Zagros second-cycle Devonian and third-cycle Permian sandstones and Alborz Palaeozoic strata indicate main magmatic flare-ups in the Arabian-Nubian Shield including the Tonian island arc magmatism, the Ediacaran post-orocline-tightening magmatism, the late Ediacaran-early Cambrian Protogonos continental arc magmatism. In addition, detrital zircons recorded the Ordovician continuation of the arc activity in the Protogonos during the early Palaeozoic. Therefore, repetitive recycling of the Neoproterozoic crystalline basement and related sedimentary cover of the Arabian-Nubian Shield, i.e., the Saharides, is a plausible source of the Devonian and Permian strata in Zagros. Our results show a close geological tie between Alborz and other Gondwana-Land-derived units in terms of Palaeozoic detritus sources which is in concordance with the location of the suture along the northern margin of the Alborz Mountains. Separation of the Alborz from the Sanandaj-Sirjan zone is accomplished by inserting from the east, the Central Iranian Blocks (Yazd, Posht-e Badam, Tabas, Lut) by strike-slip stacking and anti-clockwise rotation. This created the extensional zone of Northwest Iran.