Search

The late Jurassic Qal'eh Dokhtar Formation lithologically comprises three parts, from bottom to top, a lower sandstone unit, middle shale unit and an upper carbonate unit, which extend in a N–S direction over a wide area to the east of the Shotori Range and west of the Lut Block (Central Iran). This succession was deposited on a mixed carbonate–siliciclastic ramp. Carbonate rocks of the Qal'eh Dokhtar Formation vary from undolomitized, to partly dolomitized, to completely dolomitized. Field observations from two measured sections (the type section, 955 m thick, and the Sorond section, 639 m thick), combined with detailed petrographic and geochemical analyses, revealed the diverse types of dolomite in this formation. Five types of replacement dolomite and one type of dolomite cement were distinguished. Replacement dolomites (RD) consist of: (1) fine crystalline planar‐s (RD1); (2) medium crystalline planar‐s (RD2); (3) medium crystalline planar‐e (RD3); (4) coarse crystalline planar‐s (RD4); and (5) coarse crystalline planar‐e (RD5). Coarse crystalline planar dolomite cements (DC) were observed in low abundance and filling dissolution voids and fractures. Variation in dolomite types is mainly related to early to late diagenetic processes leading to changes in composition of the dolomitizing fluids. Replacement dolomites are non‐stoichiometric (Ca43‐56–Mg34‐45) with Sr, Mn and Fe concentrations of 41–138 ppm, 168–919 ppm and 5000–21000 ppm, respectively. These dolomites are characterized by δ18O values ranging from 0.0 to –11.8 ‰ VPDB and δ13C values of +1.1 to +3.2 ‰ VPDB. These values are depleted in δ18O relative to the postulated values for late Jurassic dolomites precipitated in equilibrium with seawater, while δ13C values are within the range of Jurassic seawater dolomite values. Fluid inclusion data of RD4, RD5 and DC yield homogenization temperatures of 72 to 118 °C. Based on petrographic, fluid inclusion microthermometric data and geochemical results, the replacement dolomites in the Qal'eh Dokhtar Formation are interpreted to have formed in the subsurface at shallow to intermediate burial depths. These dolomites were then recrystallized at increased burial depths and temperatures. Seawater was the major source of Mg2+ for early diagenetic dolomite (DR1), while Mg2+ for late diagenetic dolomites was provided from diagenesis of clay minerals in shales and mechanical compaction of mudstone in the Qal'eh Dokhtar Formation. The dolomite cement is postdated by coarsely crystalline mosaic calcite cement indicating that diagenetic fluids eventually became undersaturated with respect to dolomite and oversaturated with respect to calcite. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Two new Permian-aged formations 'Kariz Now Formation' and 'Aliyak Formation' are proposed for a 65-150 m-thick succession in the KarizNow area,with the type section for both (79.5mthick) located 9 kmnortheast of Aliyak village ca. 100 kmsoutheast of Mashhad city, northeastern Iran. The lower Kariz Now Formation is composed of siliciclastics. The age of this Formation is poorly constrained but its correlation with the Shah Zeid Formation in the Central Alborz suggests a possibleAsselian-Hermagorian age for the KarizNow Formation, which implies a hiatus of Yakhtashian-mid Midian (Artinskian-mid Capitanian) age between the siliciclastics of the Kariz Now Formation and carbonates of the disconformably overlying Aliyak Formation. There is also the possibility of a potential correlation of this Formation with the Kungurian Faraghan Formation in the Zagros area. The succeeding Aliyak Formation is mostly composed of carbonate rocks capped by a thin basaltic lava flow. The Aliyak Formation is unconformably overlain by dolostones that are correlated with the Middle Triassic Shotori Formation. Samples were collected from the Kariz Now and Aliyak formations, but fossils were only recovered from the Aliyak Formation. These include calcareous algae, small foraminiferans, fusulinids, crinoid stems and brachiopods. The recovered fusulinid assemblage from the Aliyak Formation is consistent with that of the upper Capitanian Monodiexodina kattaensis-Codonofusiella erki and Afghanella schencki-Sumatrina brevis zones of the Zagros Mountains and with the upper part of the Ruteh Fm in the Alborz Mountains. Although not radiometrically dated, the basaltic lava flow most probably corresponds to similar basaltic lava flows occurring in the uppermost part of the Ruteh Formation in Central Alborz. Thus, the Permian in the studied region developed in a basin that extended westward as far as the Central Alborz. A late Capitanian age for the Aliyak Formation implies it correlates with the Capitanian KS5 in Al Jabal Al-Akhdar in Oman, with Aliyak Unit 5 potentially representing the Permian maximum flooding surface MFS P25. [ABSTRACT FROM AUTHOR]

ABSTRACT A detailed magnetotelluric survey was conducted in 2013 in the Sehqanat oil field, southwestern Iran to map the geoelectrical structures of the sedimentary Zagros zone, particularly the boundary between the Gachsaran Formation acting as cap rock and the Asmari Formation as the reservoir. According to the electrical well logs, a large resistivity contrast exists between the two formations. The Gachsaran Formation is formed by tens to hundreds of metres of evaporites and it is highly conductive (ca. 1 Ωm-10 Ωm), and the Asmari Formation consists of dense carbonates, which are considerably more resistive (more than 100 Ωm). Broadband magnetotelluric data were collected along five southwest-northeast directed parallel lines with more than 600 stations crossing the main geological trend. Although dimensionality and strike analysis of the magnetotelluric transfer functions showed that overall they satisfied local 2D conditions, there were also strong 3D conditions found in some of the sites. Therefore, in order to obtain a more reliable image of the resistivity distribution in the Sehqanat oil field, in addition to standard 2D inversion, we investigated to what extent 3D inversion of the data was feasible and what improvements in the resistivity image could be obtained. The 2D inversion models using the determinant average of the impedance tensor depict the main resistivity structures well, whereas the estimated 3D model shows significantly more details although problems were encountered in fitting the data with the latter. Both approaches resolved the Gachsaran-Asmari transition from high conductivity to moderate conductivity. The well-known Sehqanat anticline could also be delineated throughout the 2D and 3D resistivity models as a resistive dome-shaped body in the middle parts of the magnetotelluric profiles. [ABSTRACT FROM AUTHOR]

This study characterizes the opacifiers and colouring agents used in the glazed bricks of Persepolis (mid-first millennium bc) and the Mannean site of Tepe Rabat in north-western Iran (eighth to seventh centuries bc). Various analytical studies show that lead antimonate and brizziite (NaSbO3) were used as the yellow and white opacifiers in the glazes of Persepolis and Tepe Rabat. Brizziite is shown to be incorporated in the white, green and turquoise glazes, and is also associated with lead antimonate and CaSb2O6 in some yellow and white opacifiers. The simultaneous formation of these opacifiers in one glaze might have been accidental. A possible connection between the Achaemenid glaze industry and the Mannean glaze production at Tepe Rabat is discussed. [ABSTRACT FROM AUTHOR]

The Mobarak Formation is near the town of Kiyasar in the south-east of Sari city, northern Iran. This formation conformably overlies the Geirud Formation (Upper Devonian). The lower part of the Mobarak Formation consisting of shales and thin- to medium-bedded limestone toward the top of these sequences changes into alternations of dark limestone and interbedded gray to black shales. Weathered yellow thick-bedded shales are observed at the top of the section. This formation is covered unconformably by sandstones attributed to the Dorud Formation (Lower Permian). The thickness of the formation in this region is 250 m. Four rock units have been recognized in this section. Foraminiferal biostratigraphy shows that the age of the Mobarak Formation in the Kiaysar region ranges from Lower Tournaisian to Early Middle Visean. The foraminifer Zones FAZ1 and FAZ2 are correlated with the Lower Tournaisian and Upper Tournaisian, whereas Zones FAZ3 and FAZ4 correlate with the Visean. Affinities exist between specimens recorded in the Kiyasar section with species known from other regions in eastern and Central Alborz, but there are important differences in their appearance. [ABSTRACT FROM AUTHOR]

Geochemical analysis of sandstones from the Sardar Formation (from two stratigraphic successions) in east-central Iran were used for identification of geochemical characterization of sandstones, provenance and tectonic setting. Sandstones in the two lithostratigraphic successions have similar chemical compositions suggesting a common provenance. Bulk-rock geochemistry analysis of Carboniferous sandstones from Sardar Formation indicates that they are mainly quartz dominated and are classified as quartzarenites, sublitharenites and subarkoses, derived from acid igneous to intermediate igneous rocks. Discrimination function analysis indicates that the sandstones of Sardar Formation were derived from quartzose sedimentary provenance in a recycled orogenic setting. Also, major and trace elements in sandstones of Sardar Formation (e.g., K2O/Na2O vs. SiO2) indicate deposition in a stable passive continental margin (PM). Chemical index of alteration (CIA) for these rocks (> 65%) suggests a moderate to relatively high degree of weathering in the source area. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous succession in the SE Zagros (Bandar Abbas area) is characterized by marked changes in fades and thickness. These changes relate to sediment deposition in a foreland basin along the NE margin of the Arabian plate. The succession was measured at eight outcrop sections in the Khush, Faraghun, Gahkum, Genow and Khamir anticlines. The measured sections illustrate a transition from shallow-water carbonate platform deposits (Cenomanian to Coniacian) to deep-water fades (Santonian to Maastrichtian). Outcrop observations were compared to data from ten off- and onshore wells and to a series of seismic profiles. Four cross-sections were constructed using well and outcrop data and illustrate fades and thickness variations within the Upper Cretaceous. Based on these regional profiles, the Late Cretaceous depositional history of the Bandar Abbas area was reconstructed and can be divided into two tectono-sedimentary phases suggesting a transition from a passive to an active margin. Sedimentation during Phase I (late Albion to Coniacian) took place in shallow-water carbonate platform and intrashelf basin settings (Sarvak Formation), and four third-order sequences can be recognised. The uppermost sequence is locally capped by fresh-water, pisolith-bearing carbonate sand and conglomerates with local laterite and palaeosols of the Coniacian Laffan Formation. Shallow-water facies consist mainly of wackestone to packstones with abundant benthic foraminifera. Sediments deposited in intrashelf basins are dominated by oligosteginid-bearing fades. Eustatic variations in sea level, the creation of a foreland basin and salt tectonics most probably controlled patterns of sedimentation during this phase. During the second tectono-sedimentary phase (Phase II: Santonian to Late Maastrichtian), sediments were dominated by pelagic marls and gravity flow deposits. Lateral thickness variations become more marked to the NE as a result of obduction processes and the creation of the foreland basin. Allochthonous ophiolitic and radiolarite-bearing units are common in the northern part of the Fars region but are restricted to a few localities in the Bandar Abbas area. Traces of allochthonous materials occur in the SE-most part of the Khush anticline; thrust slices in offshore seismic profiles may link to the Hawasina nappes of Oman. At the top of the Phase II succession, pelagic facies locally interfinger with Omphalocyclus and Loftusia-bearing fades (Tarbur Formation) and evaporites (Sachun Formation). These deposits are overlain by slumped and dolomitized shallow-water carbonates of the Paleocene - Eocene Jahrum Formation. The sedimentary sequence in the Bandar Abbas area illustrates a far-field response to Late Cretaceous obduction processes and foreland basin development, as well as to halokinetic activity. Rapid variations in thickness and fades document the evolution of depositional processes in the foreland basin. [ABSTRACT FROM AUTHOR]

Morphometric analysis of watersheds coupled with multi‐criteria decision making (MCDM) techniques is a widely used approach in identifying and prioritizing subwatersheds for flood risk assessment. Finding the appropriate weight for each morphometric parameter is one of the most important steps in MCDM methods. The present research focuses on analyzing the effect of using objective weighting methods in watershed prioritization in Daroungar Watershed in Northeast of Iran. To this aim, the weights of morphometric parameters were determined using six objective weighting methods and were used for ranking subwatersheds based on flood generation by a multi‐criteria model. Study results show that the highest weight in various methods belonged to different parameters. Comparison of flood susceptibility ranking maps indicated, except standard deviation method, there is a significant correlation among WM, preference selection index, criteria importance through intercriteria correlation, entropy, and method based on the removal effects of criteria methods; however, the distribution of flood susceptibility classes is not the same in the six weighting methods. The flood hazard ranking map using aggregation methods depicts that subwatersheds 6, 74, 27, and 67 which have high priority for flood hazard, have the same rank in all aggregation methods. Overall, in the present study, the importance of choosing the appropriate weighting method in prioritizing watersheds was emphasized. [ABSTRACT FROM AUTHOR]

Question: Rocky outcrops generally restrict recruitment and survival of plant species due to their environmental conditions including low soil moisture, nutrient shortages and microclimate harshness. Under such severe conditions, nurse plants may play critical roles in preserving plant biodiversity. Although the nurses' effects on plant biodiversity are fully understood in different major biomes, the relative effects of abiotic factors and nurse plants as important factors have rarely been studied in rocky outcrops, and compared to those in the surrounding rangelands. Therefore, we sought to assess the effects of two dominant shrub species (Artemisia aucheri and Prunus pseudoprostrata) on all biodiversity components including taxonomic, functional and phylogenetic diversity across some environmental gradients such as precipitation and soil gradients in rocky outcrops and their surrounding rangelands. Location: The study was conducted on six sites located in rocky outcrops and their surrounding rangelands across a precipitation gradient (160–910 mm) and under different soil fertility levels in northern Iran. Methods: We established 80 1‐m2 (1 m × 1 m) plots in each site with respect to the presence of nurse shrubs, and measured biodiversity components within the plots using Rao Q entropies (q0, q1 and q2) and mean pairwise distance (MPD) indices. The relative interaction index (RII) was also calculated to quantify the interaction type and intensity. Finally, variation partitioning analysis was performed to determine the relative importance of biotic interactions and abiotic factors such as precipitation, electrical conductivity (EC) and phosphorus on structuring biodiversity components. Results: Plant–plant interactions and abiotic factors consistently influenced different components of biodiversity in rocky outcrops and their surrounding rangelands. However, nurse shrubs showed stronger effects on plant biodiversity than abiotic factors by providing suitable microenvironments to harbor less‐tolerant plant species under the severe conditions of outcrops. In addition, microhabitats beneath nurse shrubs significantly responded to soil EC and precipitation gradients, with a decrease in competition intensity under intermediate levels of the gradients. In contrast, nurse shrubs negatively affected different components of biodiversity, with a decrease in biodiversity under intermediate levels of environmental gradients in surrounding rangelands. Conclusions: Our findings show critical roles of nurse shrubs for maintaining plant biodiversity in rocky outcrops depending on their growth form and the biodiversity component considered. In this case, nurse shrubs could reduce double environmental filtering, consistent with establishing a functional paradox trade‐off to support a wide range of plant species with functionally divergent relatedness. [ABSTRACT FROM AUTHOR]

Soft sedimentary rocks are frequently found in many mountainous regions of the world like Zagros Mountains located in the south and west of Iran, where most of Iran's water conveyance projects have been constructed or are under construction. These rocks usually contain considerable amounts of different types of clay minerals. The clay mineral‐rich rocks cause many problems in the deep and long mechanised tunnelling projects. In particular, the boreability of these rocks is very different from other rocks, and due to their plastic behaviour and the lack of complete formation of chips during the cutting process by disc cutters, the prediction of cutterhead penetration in these rocks, with existing models, is often inaccurate. In this paper, a new model for estimating the disc cutter penetration in these rocks is introduced, which is based on data obtained from the main tunnelling projects completed in sedimentary rocks of Zagros Mountains. Then, the validity of the developed model is checked using actual data obtained from a tunnel recently constructed in the area. The new model can offer a more accurate estimate of machine performance in similar rocks. [ABSTRACT FROM AUTHOR]

Onosma atrii and O. persica are described and illustrated as new species and O. caucasica Levin is recorded for the first time from northwestern Iran. The two new species are placed in subsect. Asterotricha (Boiss.) Gürke, because of the asterotrichous indumentum (stellate trichomes) of their basal leaves. An extensive review of the literature and comparison with specimens from various European and Asiatic herbaria led to the recognition of these novelties. Our argument for these innovations is based on observation of significant differences in taxonomically important morphological characters including trichome type, shape and size of basal and cauline leaves, shape and size of calyx and corolla, annulus hairs, anther length, connection type and degree of exsertion, and nutlet morphology. The diagnostic morphological characters of closely related species are discussed, and for each new species a detailed description and details of distribution and conservation status are provided. An updated synoptical key to the species known from the Flora Iranica region and Atropatene sub‐province is provided. [ABSTRACT FROM AUTHOR]

Geochemical data for 435 samples of the Pliocene to Quaternary (P–Q) volcanic rocks from Iran, distributed mostly along a NW–SE trending belt, were compiled from 28 papers (12 written in Persian). Until now, the rock nomenclature employed has been inconsistent with the recommendations of the International Union of Geological Sciences (IUGS). Moreover, older bivariate and ternary tectonic discrimination diagrams and only traditional qualitative approaches using Nb and Ta anomalies, have been used to understand the origin and evolution of the P–Q magmas. The P–Q magma and rock types were classified by strictly following the IUGS recommendations. Two geochemometric multidimensional models based on 10 and 16 elements, along with two decision procedures, capable of discriminating 29 fine tectonic settings, were used to document the existence of six tectonic settings in Iran during the P–Q. The rare earth elements indicated that the evolved intermediate and silicic rocks had a significant crustal component in their origin. The quantification of Nb and Ta anomalies in multielement diagrams was used to support the tectonic inferences from the multidimensional geochemometric models. [ABSTRACT FROM AUTHOR]

Finding abundant sources of drinking water is a must in practically every country throughout the world. The issue is even more dire in arid and semi‐arid regions, such as Iran, where the shortage of healthy drinking water is quite serious. Finding and maintaining groundwater resources is therefore potentially the best alternative for supplying the water demand of the country. Accordingly, this study aims to assess the potential of karstic areas as a major source of water supply in southwestern regions of the Maharlou watershed, Iran. For this purpose, a combination of fuzzy‐AHP (analytical hierarchy process) and DST (Dempster‐Shafer Theory) methods are used to locate suitable karstic regions in the study area. Karstic zone maps were also generated using a variety of parameters including lithology, fault, precipitation, elevation, temperature, river and slope. Fuzzy maps were also produced using fuzzy membership functions for each parameter, after which the AHP approach was incorporated to assign weights to each layer and eventually generate the final fuzzy‐AHP map. Ultimately, the DST model was used at three confidence intervals of 99.5%, 99%, and 95%. Based on the final results of the fuzzy‐AHP method, approximately 30% of the study region was unsuitable in terms of access to karstic areas, whereas unsuitable zones obtained using the DST method contributed to about 41%, 44%, and 46% of the study region at 95%, 99%, and 99.5% confidence levels, respectively. Taking into account the fact that reductions in the distance from faults increases the probability of the presence of karst regions (with other parameters being constant), by comparing the results of the two models with fault maps, it was determined that the DST model achieves higher accuracy. The DST method is among common methods employed to predict suitable karstic regions, which ultimately produces different maps based on the configured confidence level. Key Points: For determination of karst suitable area fuzzy and DST (Dempster‐Shafer theory) model were usedAnalytical hierarchy process was used for weighting each input data based on expert comments in ArcGIS softwareUsing DST method was prepared karst suitable area maps with different levels of confidence [ABSTRACT FROM AUTHOR]

A total of 64 samples were collected from the Kazhdumi Formation (Albian) of south Zagros Basin (Coastal Fars Zone) in order to study the biostratigraphy and analyse the lithofacies. Stratigraphic distribution of identified larger benthic and planktonic foraminifers has confirmed the presence of three successive biozones: Mesorbitolina subconcava‐Orbitolina discoidea Zone, Favusella washitensis Zone followed by an upper Conicorbitolina conica‐Mesorbitolina parva Zone. Generally, orbitolinids are well developed in the Albian succession in the studied section, whereas the stratigraphic distribution of planktonic foraminifers is more restricted, dominating the Favusella washitensis Zone. Nevertheless, microscopic investigation recognizes five microfacies consisting of extraclast‐foraminifer packstone, peloid‐intraclast Orbitolina wackestone, foraminiferal plankton wackestone, intraclast‐Orbitolina grainstone, and coral‐rudist wackestone, which indicated a shallow water carbonates palaeoenvironment (intertidal, lagoon, bar) and open marine. The alternation of both planktic and benthic foraminifera through the Kazhdumi Formation confirms a rapid transgression and regression in the studied section during Albian time, which is attributed to Kazerun basement fault behaviour in the mentioned time interval. [ABSTRACT FROM AUTHOR]

Iran's groundwater hydrochemistry has not been well understood. In this study, Iran's groundwater hydrochemistry is evaluated using a rich, ground‐trusted data sampled from 9,468 wells distributed across the country in 2011. Twelve groundwater quality parameters were analyzed in each sample, resulting in 113,616 parameters over the study period. Examination of anions‐cations shows that concentrations of sodium, calcium, chloride, and sulphate are higher than the acceptable threshold for drinking‐use suggested by the World Health Organization in about 40%, 21%, 25%, and 20% of the samples, respectively. The results of the water quality index reveal that most of the groundwater resources in the central, southern and eastern regions of Iran, which supply the majority of the domestic water for populated cities, do not meet the requirements for drinking‐use. Although the groundwater in northern parts fulfills the requirements for irrigation‐use, it is only suitable for irrigation of salinity‐friendly crops in central, eastern and southern regions. Ionic types and hydrochemistry facies indicate the dominance of mix water type in 13 out of 30 of Iran's sub‐basins, followed by sodium‐chloride water type in nine sub‐basins. Local geology and lithology are mainly attributed to the distribution of groundwater facies in Iran. In general, our findings reveal a distinctive relationship between Iran's geological‐geomorphological features and hydrochemical facies/groundwater quality. The findings can be used in the formulation of new strategies and policies for Iran's groundwater quality management in the future. Key Points: Since Iran's groundwater hydrochemistry has not been well understood, we explored it using a rich, nationwide data sampled from 9,468 wellsFindings indicate the dominance of mix water type in 13 out of 30 of Iran's sub‐basins, followed by NaCl water type in nine sub‐basinsA distinctive relationship exists between Iran's geological‐geomorphological features and hydrochemical facies/groundwater quality [ABSTRACT FROM AUTHOR]

The main purpose of this study is to evaluate the feasibility of geologic CO2 sequestration in terms of CO2‐brine‐rock interactions in Ramin oil field, Iran. Static experiments were conducted with carbonate rocks at 70°C and atmospheric pressure for 14, 30, and 60 days. CO2‐brine‐rock interactions were inferred from the evaluation of Ca2+, Mg2+, Cl−, and SO42− concentrations and a thorough characterization of the carbonate rocks before and after treatment. Scanning electron microscopy (SEM) micrographs revealed the formation of dissolution pits and the growth of new structures. Energy dispersive X‐ray spectroscopy (EDS) and X‐ray diffraction (XRD) indicated these minerals to be calcite. Porosity of the carbonate rocks increased from an initial value of 4.72% to the maximum value of 11.83%. Then, it decreased to a value of 5.48% until the end of the experiments, that is, 60 days. Chemical analysis of brine suggested the precipitation and dissolution of calcium sulfate. In addition, dolomite dissolution and halite precipitation/dissolution were inferred. Calcite precipitation and porosity reduction suggested that CO2 can be stored via mineral entrapment in the Ramin oil field, which is desired from the perspective of CO2 geologic sequestration. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Study of interactions between surface‐water and pore‐water in lakes is complicated due to spatio‐temporal heterogeneities in flow condition across the sediment–water interface. In this study, seasonal hypersaline Maharlu Lake was investigated by collecting surface‐water and pore‐water samples from four nests of multilevel piezometers installed at different distances from the inflow of rivers to the lake. The hydraulic heads in the piezometers as well as vertical profiles of Mg+2, Na/Cl, and Br/Cl were used to investigate both hydraulic and geochemical interactions between surface‐water and pore‐water in the lake. Depletion of lake surface water and pore water with respect to B, Br, Li+, K+, Mg2+ and the absence of Mg‐K chlorides and sulphates in the lake bed sediments is probably due to leakage of highly evaporated residual brine from the lake. Hydraulic gradients in the multilevel piezometric nests indicate that a general downward flow from surface‐water to pore‐water occurs across sediment–water interface. Vertical profiles of Br/Cl, Mg2+, and Na/Cl showed that the maximum flow rate was more than 1 m/yr close to the mouth of the inflowing rivers. The downward vertical flow was limited in the area far from the inflowing rivers due to the presence of an impermeable confining halite layer which interrupts the hydraulic connection between shallow pore water (less than 50 cm deep) and deeper zones. The hydraulic and geochemical interactions between surface‐water and pore‐water across sediment–water interface in the Maharlu Lake are of interest to find out the fate of pollutants and their distribution in the lake. [ABSTRACT FROM AUTHOR]

Projections of potential impacts of climate change and groundwater abstraction on gaining and losing streams, particularly in ephemeral river basins exhibiting sporadic and intricate flux exchanges, have remained largely unexplored. To fill this gap, we propose a promising modeling scheme based on the new fully integrated hydrological model SWAT‐MODFLOW‐NWT, calibrated and validated for 1978–2012, to quantify the intertwined surface‐groundwater interactions under a conjuncture of three climatic emission scenarios (RCP 2.6, 4.5 and 8.5) and two groundwater pumping variants: "pumping" (extending current groundwater utilization into the future) and "nonpumping" (assuming a complete cease of pumping in the future). By forcing the integrated model with future downscaled climate predictors of CanESM2 under the aforementioned RCPs for three time slices up to year 2100, projections of various water resources components for the Gharehsoo River Basin (GRB), in northwestern Iran were made. Results demonstrate that because of a general decrease of future precipitation, though with ups and downs across the total projection period, most of the surface and ‐subsurface budget quantities and fluxes are substantially affected. In particular, future groundwater discharge (baseflow) to the gaining streams will be more influenced by the "pumping" variant (increasing and decreasing for "nonpumping" and "pumping", respectively) than the concentrated groundwater recharge from the losing streams (decreasing and increasing for "nonpumping" and "pumping", respectively). Future water yield and groundwater storage will also diminish and, surprisingly, this cannot be alleviated by future "nonpumping", indicating the groundwater overutilization is the compelling reason for the future water scarcity in the GRB, rather than climate change alone. Plain Language Summary: Understanding climate change impacts on surface‐groundwater interactions, accommodating nearly all of water resources components of a watershed, is of paramount importance in devising effective strategies to alleviate the adverse impacts of climate change. This is particularly important in semiarid regions where the surface water scarcity has markedly increased the dependency on groundwater resources which, in turn, has highly affected the interaction between these two. We have provided an innovative scheme to assess and project climate change impacts on water resources of a basin and, in particularly, on gaining and losing streams at different temporal and spatial scales. In addition, the net impacts of climate change impacts on the quantity of the water resources, compared with the groundwater overutilization, can be quantified using the proposed methodological approach. Our findings importantly highlight that the groundwater overutilization is the major reason, rather than climate change impacts, for extreme groundwater storage depletion in the Gharehsoo River Basin, in northwestern Iran. As a result, groundwater discharge to the river network will diminish tremendously under the changing climate projected for the region. Key Points: A promising integrated hydrological modeling approach is proposed to assess the future effects of climate change and groundwater pumpingGaining streams will be more impacted by the climate change scenarios and pumping variants than losing streamsGroundwater overutilization turns out to be the major reason for the extreme groundwater storage drawdown in the aquifer of the Gharehsoo River Basin, Iran [ABSTRACT FROM AUTHOR]

Groundwater resources in special have been applied for drinking water use versus surface water in Iran. However, this groundwater withdrawal has not been monitored for its level and quality. The present study aimed at determining the qualitative changes of Hamedan groundwater resources using the Kriging and analysis of quality assurance approach. To investigate the spatial variations of water quality in Hamedan, the following physical parameters were taken into consideration: total dissolved solid and electrical conductivity; chemical agents including calcium, magnesium, sodium adsorption ratio, iron, fluoride, sulfate, nitrate, phosphate; residual concentrations of pesticides in drinking water, including organochlorine (difenoconazole and permethrin), organophosphate (chlorpyrifos, diazinon, and malathion), and pyrethroids (fenvalerate); and heavy metals including cadmium, lead, arsenic, mercury, chromium, copper, and zinc. The geographic information system (ArcGIS10.4) was used to draw the isopotential maps of the resources. Schuler, Piper, and Durov diagrams as well as AqQA software were used to determine the water quality. According to Shuler's diagram, samples of drinking water in Hamedan vary from moderate to good in terms of quality. The concentration of physicochemical parameters in the north, northwest, and northeast of Hamedan was higher than the World Health Organization (WHO) guidelines. The residual concentrations of pesticides, arsenic, mercury, chromium, and cadmium were lower than the WHO guidelines. However, the concentrations of copper and zinc in northern Hamedan were higher than the guidelines. According to the geological map of the plains of Hamedan, it can be concluded that the source rock mainly consists of dolomite and igneous rock is made of alkaline‐basaltic feldspar. Variations in the chemical composition of drinking water in Hamedan depend on the amount of precipitation, soil, water harvesting, excessive use of fertilizers and human activities. [ABSTRACT FROM AUTHOR]

SHRIMP U–Pb dating of zircon from two representative samples of the Bardkish syenitic pluton, Urumieh plutonic complex, northwestern Iran, yielded a Late Cretaceous weighted mean 206Pb/238U age of 91.1 ±0.8 Ma (Turonian). The pluton is characterized by high K2O content, Ti–Nb–Ta depletion, enrichment in light rare earth elements and large ion lithophile elements compared to high field strength element, Mg‐rich biotite and calcic amphibole, suggesting a shoshonitic affinity. Geochemical features of the Bardkish syenite are consistent with derivation by fractional crystallization of initial mafic parent magmas. It is most likely that primary magma of the syenite originated from a metasomatized subcontinental lithospheric mantle source with minor crustal component, and underwent a fractional crystallization process during its emplacement. The estimates of trapping pressures and temperatures suggest that crystallization began at the middle crustal level (less than 11 km) near 700–730 °C. The generation of the Bardkish syenite could be related to the subduction of Neo‐Tethyan oceanic crust beneath the Central Iranian microcontinent and it possibly marks a major magmatic episode prior to the final closure of the Neo‐Tethyan ocean in northwest Iran. [ABSTRACT FROM AUTHOR]

Abstract: Soil erosion is a worldwide threat that results in soil degradation, agriculture abandonment, and crop yield reduction. There is a need to find methods to survey soil erosion rates in order to improve and develop sustainable land planning. The present study utilizes new approaches based on the fuzzy set both in designing the problem (through the fuzzy decision making trial and evaluation laboratory) and in prioritizing the effective factors to mitigate soil erosion (using a fuzzy analytical network process, FANP). This study is first to apply these methods to soil erosion. A set of geo‐environmental factors influencing soil erosion was characterized to evaluate the potential risk of soil erosion in the Nor‐Rood watershed in Iran. The layers of information were developed using expert knowledge, and a network structure was designed by the fuzzy decision making trial and evaluation laboratory method. Then, the weights of layers were calculated by the FANP method by considering the internal and external interaction between factors. The erosion susceptibility map was produced by combining layers based on their weights in a geographic information system platform and was validated using erosion occurrences recorded in field surveys. Results revealed that FANP model accuracy is high (83.4% accuracy) for the study area. We found that vegetation, drainage density, land use, and soil erodibility are the key parameters to explain the soil erosion rates. The soil erosion risk map developed by the FANP method provides useful information for sustainable planning and risk mitigation and can be used in a data‐poor environment. [ABSTRACT FROM AUTHOR]

Copyright of Island Arc is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Assessing the effectiveness of conservation practices under changed climatic conditions has proven to be invaluable in selecting the adaptation practices. Conservationists are concerned that past effective practices may no longer be effective in the future climate change. This research is aimed at assessing the effectiveness of soil and water conservation practices under future climate change, with respect to sediment yield leaving a watershed. For this purpose, the Soil and Water Assessment Tool, SWAT, was applied to simulate various climate change scenarios with three soil and water conservation practices to assess possible changes in stream flow, and sediment yield of the Gorganroud watershed in the northern part of Iran. Study results demonstrated that the impact of climate change in the increase of watershed sediment yield is more than the stream flow and varies from 35.9 to 47.7% for the period 2040-2069. Implementing conservation practices under climate change can reduce the sediment yield of watershed up to 7.2% and for the sub-basin scale up to 46.4%. Range management practices were found to be the most effective practice in the decrease of sediment at the sub-basin scale and porous gully plugs and terrace construction, the most effective at the watershed scale. The results indicate that soil and water conservation practices will be more effective at reducing sediment yields under anticipated future climates. Though, implementation of each conservation practice solely was not sufficient to compensate for climate change-driven increases in sediment yield. This study provides valuable information for watershed managers and decision makers regarding selection of soil and water conservation practices for adaptation to climate change. [ABSTRACT FROM AUTHOR]

Tertiary-relict Hyrcanian (Caspian) forest along the shores of the southern Caspian Sea is a center of biodiversity. Still, there is little information on plant diversity patterns in this area. This study evaluated plant diversity, variation in life forms, and geographical distribution of the zonal vegetation types and their relationships with environmental variables, in the educational and experimental forest of Kheyrudkenar, an important protected area in the central Hyrcanian forest of northern Iran. For this purpose, 226 vegetation plots of 400 m2 were laid out along two altitudinal transects from the lowlands (100 m a.s.l.) to the timberline (2000 m a.s.l.). Four vegetation types were identified using modified TWINSPAN, indirect and direct gradient analyses. Species-related (species diversity indices, life form and phytogeographical elements) and environmental variables (climate, topographic and soil variables) were calculated and subjected to one-way ANOVA among the vegetation types. Both constrained (CCA) and unconstrained (DCA) ordination analyses showed an almost identical variation of the floristic composition along their axes and demonstrated that there are two main gradients in the Hyrcanian forest. Elevation together with annual precipitation and mean annual temperature were the most important factors controlling the floristic composition in the area. Topographic features such as slope inclination and heat index were found to be important within an elevation zone/vegetation type. Soil physical and chemical properties were of secondary importance for the separation of the vegetation types. This knowledge will be useful for forest management and conservation practices in the Hyrcanian area with its distinct and unique flora and vegetation. [ABSTRACT FROM AUTHOR]

The article discusses the groundwater quality in the semi-arid region of the Chahardouly basin in the western part of Iran. It cites that the development of the main aquifer systems are within the alluvial deposits. In addition, It also cites that the availability of groundwater is rather erratic owing to the occurrence of hard rock formation and a saline zone in some parts of the area. It analyses the Groundwater samples collected from shallow and deep wells to examine the high quality characteristics of groundwater. Moreover, it suggests that the occurrence of saline groundwater, as witnessed by the high electrical conductivity (EC), may be attributed to the long residence time of water and the dissolution of minerals, as well as evaporation of rainfall and irrigation return flow.