The karst springs of Belqis and Siah are among the abundant springs of Kohgiluyeh and BoyerAhmad provinces that are discharged from the Asmari limestones of the Lar anticline. The protruding surface of the Asmari limestones of the anticline is not proportional to the volume of water discharged from these springs. Based on the summary balance and hydrograph of the springs discharge, there are important water sources in the study area (including the Nile anticline) that can interfere with the recharge of the mentioned springs. Therefore, to evaluate this issue, the value of stable isotopes of oxygen (18O) and hydrogen (2H) of all water sources in the target area (discharge) and in the recharge area was determined for two periods (May 2023 and May 2024). Then, using these isotopic results and the local watershed line (LMWL), the source of recharge of the springs in the target area was investigated, and the height of the recharge area and the possible recharge share of these springs from the water sources in the area were determined. The results showed that the elevation of the recharge area of the springs in the target area corresponds to their elevation in the Nile karst anticline. However, the share of water received by the Siah Spring is slightly higher compared to the water received by the Belqis Spring from the Nile anticline.
The Sabzevar aquifer is one of the important groundwater resources in arid regions of the Khorasan Razavi Province. The different usages from this scarce resource, leads to a quantitative and qualitative crisis. The water level from 50 piezometric and physico-chemical properties of 25 groundwater samples were used to determine the hydrogeological setting and salinity origin of the aquifer. The iso-potential map shows that the groundwater flow directions are mainly from eastern to the western part of the area, which is closely aligned with surface flow direction. In general, the aquifer recharged mainly from the limestone heights of the northern parts of the area. The adjacent Ataeiyeh Plain in the eastern part is also an underground inflow to the aquifer. An ephemeral saline river also flows from the east to the west part of the area. Electrical conductivity varies between 627 µs/cm in the recharge areas in the north of the aquifer to 11,600 µs/cm in the middle part of the aquifer. Groundwater samples are classified based on the electrical conductivity into three groups: freshwater with an electrical conductivity of less than 1000 µs/cm and the sodium bicarbonate type in the north of the aquifer, brackish waters with 1000 4000 µs/cm and the sodium chloride type in the middle part of the aquifer. The water samples are saturated with calcite and dolomite and under-saturated with gypsum and halite. The salinity of the groundwater in the region is dependent on dissolution of evaporative formations in the region. Therefore, the infiltration of fresh water from the northern parts and some extent from the southern part, along with the infiltration of saline water from the eastern parts and the adjacent aquifer, are the main factors controlling the quality of the groundwater of the plain, along with ion exchange and mixing processes.
This study evaluates the groundwater quality near the Mohammadabad municipal solid waste landfill in Qazvin, Iran, by examining the physical and chemical parameters of the water. The physicochemical parameters, major ions, and heavy metals in the water were investigated using indices such as the Water Quality Index (WQI). In the wet season, the concentrations of chloride (339.8 mg/L), sulfate (365 mg/L), and sodium (268.7 mg/L), as well as electrical conductivity (EC) with an average of 13035 µS/cm and total dissolved solids (TDS) with an average of 9338.1 mg/L, were significantly higher than the permissible limits of WHO and EPA. In the wet season, the concentrations of some heavy metals such as Pb and Ni exceeded WHO standards, averaging 23.7 µg/L and 49.3 µg/L, respectively. However, in the dry season, metal concentrations decreased, although in the monitoring wells, the average levels of heavy metals in the order of Fe > Zn > Pb > Mn > As > Ni > Hg still exceeded the permissible limits of WHO and EPA. Water Quality Index (WQI) results showed that 27.5% of the samples in the wet season and 8% in the dry season had unsuitable quality for drinking purposes. The stations located near the landfill exhibited the poorest water quality in both seasons. The results from Piper and Gibbs diagrams indicated that the dominant water type in the area is chloro-sulfate, and processes such as evaporation and interaction with evaporitic sediments play a major role in shaping the groundwater chemistry.
3D reconstruction plays an important role in surveying and close-range photogrammetry, facilitating the accurate extraction of geometric information from objects and their surrounding environment. However, conventional methods in this field typically require multi-view images along with positional and angular data of the camera, which can pose limitations in certain practical applications. This study introduces a novel approach based on the MiDaS deep learning model, one of the most accurate architectures for monocular depth estimation, which is capable of generating a relative depth map from a single 2D image. The final 3D model is then extracted using the Poisson Surface Reconstruction algorithm, without the need for spatial information or camera orientation data. To evaluate the performance of the proposed method, the resulting 3D model was compared against a reference model produced by the conventional photogrammetry method. The results showed a Root Mean Square Error (RMSE) of 0.775 centimeters, confirming the appropriate accuracy and reliability of the proposed approach under multi-view data limitations. This study demonstrates the high potential of deep learning models like MiDaS in 3D reconstruction and surveying applications, and highlights that using more advanced versions such as DPT could further improve accuracy in future research and applications.
This study investigates deformation in the Chai-Kour metamorphic complex, located in the Sanandaj-Sirjan metamorphic belt, using structural, microstructural, and strain analyses. Field observations show that this area has been affected by a complex deformation system resulting from the interaction of three deformation phases. The structural and microstructural analyses conducted provide evidence for the activity of a transperssion in this region. Presence of diverse structures, including asymmetric folds, sheath folds, and asymmetric boudins, all indicative of intense and heterogeneous deformation conditions. At the microscopic scale, the identification of sigma and delta porphyroclasts, S/C fabrics, and fish-shaped micas not only confirms a dextral shear sense (top-to-the-SE) but also provides valuable insights into the temperature conditions prevailing in the region. Quantitative strain analyses using the Fry methods and Flinn diagram demonstrated that the strain ellipsoid in this area exhibits a clear tendency toward plane-flattening strain. K values (0.51-1.18) and D values (1.1-2.22) indicate significant heterogeneity in strain distribution across the region. The calculated vorticity number (0.75–0.83) revealed that the deformation flow in the region was predominantly non-coaxial, with a simple shear component playing a more dominant role than pure shear. Examination of quartz and feldspar microstructures, including subgrain rotation (SGR) and grain boundary migration (GBM) recrystallization, suggests a temperature range of 400–650 °C for the main deformation event, consistent with amphibolite facies conditions. Additionally, the presence of quartz BLG recrystallization and brittle structures like book-shelf in feldspars indicates the occurrence of late-stage deformation under lower temperature conditions. These findings are in complete agreement with the region's tectonic setting within the framework of oblique convergence between the Eurasian and Arabian plates.
The Fahliyan Formation, as one of the most important hydrocarbon reservoirs in southwestern Iran, exhibits significant geological and reservoir complexities. This study integrates petrophysical data, pressure data, and core analysis to perform comprehensive reservoir characterization and zonation. Through integrated analytical methods, reservoir layers with similar petrophysical properties and flow behavior were identified and classified. The research utilized wireline log data (gamma ray, neutron, density, and resistivity logs) from an oil field in the Abadan Plain region, employing probabilistic petrophysical evaluation in Geolog software to assess the Fahliyan Formation's reservoir quality and determine key parameters including porosity, water saturation, and lithology. Core laboratory data from porosity analysis and petrographic studies were used for validation. Reservoir pressure data served as a critical tool for precise zonation control and identification of independent hydraulic units. Results reveal the Fahliyan Formation's high degree of heterogeneity, with the reservoir divided into 10 zones in Well A and 12 zones in Well B. The most productive zones were identified as F3, F5, F7, F9, and F10 in Well A and F5, F7, F9, and F11 in Well B, which contribute significantly to oil production. However, impermeable and compacted zones (F6, F8, and F10 in Well B) create hydraulic barriers between adjacent zones, as confirmed by petrophysical log responses. This study demonstrates that the integrated approach combining petrophysical analysis, core data, and pressure measurements provides an effective methodology for accurate reservoir zonation and identification of productive intervals in this complex carbonate formation, offering valuable insights for field development planning and optimal hydrocarbon recovery from the heterogeneous Fahliyan reservoir.
The Meiduk porphyry Cu ـ Mo deposit is located in the southern part of the Urumieh–Dokhtar magmatic arc within the Cenozoic magmatic belt of Kerman, Iran. Due to the widespread occurrence of magnetite as a minor phase in potassic and phyllic alteration zones, this deposit provides a suitable context for geochemical investigations. In this study samples were analyzed using Electron Probe Micro-Analyzer (EPMA) to assess the physicochemical conditions of magnetite formation. Elemental data indicate that the magnetites are predominantly of hydrothermal origin, characterized by high Ti and V and relatively low Al and Mn contents. These compositions suggest formation temperatures of 200–300°C. The chemical composition, especially Ti/V ratios and trace element distributions such as Co, Ni, and Cr, effectively distinguishes between magmatic and hydrothermal magnetites. Geochemical plots confirm that the studied magnetites fall within the porphyry field. Petrographic evidence, including the occurrence of magnetite in association with sulfide minerals such as chalcopyrite and pyrite, strongly supports the geochemical findings. This study highlights the potential of magnetite chemistry as a powerful tool for deciphering ore-forming processes in porphyry systems and demonstrates its applicability in exploration and modeling of concealed or deep-seated mineral deposits.
Accurate land cover classification is a fundamental step in engineering geology studies, particularly for assessing slope instability and mass movements. With the growing availability of satellite data and machine learning tools, automated and reproducible classification frameworks have become essential. This study presents a comprehensive Python-based framework for land cover classification, comparing the performance of two machine learning algorithms, Support Vector Machine (SVM, supervised) and K-means clustering (unsupervised), against traditional spectral indices (NDVI, NDWI, UI, SAVI) using Landsat 8 imagery. The study area is located in East Azerbaijan Province, Iran, covering approximately 80×70 km with diverse land cover types, including vegetation, bare soil, urban areas, and surface water. Prior to classification, data underwent several preprocessing steps: gamma correction for visual enhancement, Min-Max normalization for data scaling, and Principal Component Analysis (PCA) for dimensionality reduction and multicollinearity mitigation. PCA retained components explaining at least 95% of total variance. Classification was performed on four main classes. Results were evaluated using Overall Accuracy (OA), Kappa Coefficient, and weighted Precision, Recall, and F1-Score. The SVM algorithm, using an RBF kernel, achieved the highest accuracy with 84% OA and a Kappa of 0.81, demonstrating superior ability in defining clear class boundaries, particularly in distinguishing urban areas from bare soil. In contrast, K-means clustering yielded 73% OA and a Kappa of 0.68, with noticeable class overlap. Spectral indices alone provided a baseline accuracy of ~65%, but their integration with machine learning models significantly improved performance. The findings confirm that supervised machine learning models, particularly SVM, outperform unsupervised clustering and standalone spectral indices. However, K-means remains viable in data-scarce scenarios. The proposed Python-based workflow offers a reproducible, transparent, and efficient approach for land cover analysis, making it a valuable tool for engineering geology applications such as landslide susceptibility mapping.
Accurate estimation of hydrodynamic parameters is essential for sustainable aquifer development. Since Theis (1935), the Type Curve Matching Technique (TCMT) has been used to estimate aquifer parameters. This method is associated with graphical errors. In this study, a supervised AI committee machine was used to eliminate errors and accurately estimate the hydrodynamic parameters of confined aquifers with high ability to approximate functions as an alternative to the conventional TCMT method and existing AI methods. In this study, pumping test data were considered as input components and the coordinates of the optimal point were considered as the output. To reduce the dimensions of the input components, the principal component analysis (PCA) technique was used. Then, the matching point coordinates were combined with the analytical solution of Theis (1935) and the values of the aquifer parameters were calculated. To develop this machine, in the first step, three ANNs with different training algorithms, Levenberg–Marquardt (LM), gradient descent (GD), resilient back-propagation (RP), were developed to determine the match point and estimate the hydrodynamic parameters of the confined aquifer. Based on the modeling results, all models showed a good approximation of the hydrodynamic parameters of the confined aquifer. Then, in the second step, considering the complexity of hydrogeological systems, a committee machine consisting of three artificial intelligence models was designed and built, which used the capabilities of all three models to determine the hydrodynamic parameters of the confined aquifers. The models' outputs were combined using a supervised nonlinear combiner, yielding highly accurate final results. The results showed that the proposed committee machine model is more accurate, and better alternative to TCMT methods and artificial intelligence methods in determining the optimal match point and estimating the hydrodynamic parameters of the confined aquifer.
The Aregijeh and Emarat Pb-Zn deposits are hosted by clastic-carbonate sequences of the Early Cretaceous in south Arak. These deposits formed in the northern Sanandaj-Sirjan zone within an intracontinental rift setting. The main stratabound Pb-Zn mineralization horizon occurs in the upper part of thick-bedded Orbitolina-bearing limestones (Aptian-Albian), underlying shales and marls with intercalated thin-bedded limestones. Mineralization appears as banded, brecciated, laminated, veined, and disseminated comprising sphalerite, galena, and pyrite, with minor chalcopyrite, and Ag-Sb-Cu sulfosalts, accompanied by quartz, dolomite, calcite, barite, and siderite as gangue minerals. Silicification and carbonatization represent the dominant alteration types. The unusual abundance of fine-grained quartz, anhedral dolomite, and framboidal pyrite provides evidence of early diagenetic stages, while mineralization was completed by the precipitation of coarse-grained quartz, euhedral dolomite, siderite, and hydrothermal sulfides. Ore formation occurred in a submarine anoxic environment shortly after sedimentation. Microthermometric results of fluid inclusions reveal similar homogenization temperature ranges (125–207°C in Aregijeh vs. 130–217°C in Emarat) in both deposits. However, calculated salinities (7.59–13.72 wt.% NaCl equiv. in Aregijeh vs. 7.59–19.84 wt.% NaCl equiv. in Emarat) are higher in the Emarat deposit. Textural relationships, mineralogical properties, and fluid inclusion data suggest mineralization formed from basinal brines during diagenesis in a reduced environment, consistent with Irish-type deposits.
Oil shales, as an important hydrocarbon source, require careful investigation in terms of the distribution of various elements. Geochemical models are a powerful tool for understanding the distribution of elements and the factors affecting them, and help optimize the exploration and exploitation of these resources. Geochemical interpretations are also used to identify anomalies, and reserves, and determine their composition. Therefore, in this study, to determine the distribution of various elements in sedimentary deposits containing oil shales, the main focus has been on the effect of oxidation-reduction conditions and climate of the source rock formation environment. For this purpose, to evaluate the deposits around the Qolyan River in the Qalikuh region of Lorestan, 15 surface samples were taken from these deposits and subjected to XRD and ICP analyses. Also, 80 thin microscopic sections were prepared for petrographic examination. Rock-Eval Pyrolysis analysis was also performed to determine the total organic matter content of oil shale samples. The results of geochemical models showed that detrital minerals (quartz, clay minerals) and carbonate minerals (calcite, dolomite) are the main minerals in the aforementioned deposits. These deposits are equivalent to intermediate-intermediate felsic igneous rocks and are located in the arkose, litharenite, and shale ranges, which were formed in a subduction and collisional environment. The average values of weathering indices and oxidation-reduction condition determination indices confirm the relatively mild weathering of the deposits, which are located in the dry climate zone and, with little maturity, have not yet reached the sedimentary cycle and were formed in a reduction environment. The main factors of geochemical changes in this study are: Weathering rate (oxides Al2O3, MnO, Na2O, TiO2, MgO), zircon mineral (rare earth elements and minor elements such as: Th, Zr, Nb, Ta), development of total organic matter (TOC) in oil shales under environment of reduction conditions (Ni، U، V، Co، Cr), dispersion of clay minerals (Cu, Zn), adsorption-repulsion phenomena and substitution of ions (Sr), alteration (Rb).
The Saheb skarn iron deposit is located about 16 km northwest of the Saheb district, in Saqez city, Kurdistan Province. This area lies within the Sanandaj-Sirjan metamorphic-magmatic zone. The main rock units in the study area include dolomitic rocks of the Soltanieh Formation, Permian and Cretaceous limestones, shale and granitoid batholith. The Saheb batholith shows quartz monzodiorite, quartz monzonite and granite in composition. This batholith has intruded into Permian and Cretaceous sedimentary units during the Late Cretaceous-Early Palaeocene, causing contact metamorphism and skarnification. The contact metamorphism zone in the area includes endoskarn and exoskarn zones and garnet skarn, garnet pyroxene skarn, pyroxene skarn, epidote skarn, marble and mineralized skarn subzones. The Saheb iron mineralization has vein and lenzoid-shape with a length of 20 to 100 m and a thickness of 3 to 10 m which formed within marble and hornfelsic units (exoskarn) and to a lesser extent in the intrusive mass (endoskarn). The ore bodies occur as massive, brecciated, open space filling, banded, vein-veinlet, disseminated and relict. Magnetite is the main ore mineral, which is accompanied by pyrite, chalcopyrite, and secondary minerals such as hematite, goethite, azurite, chalcocite, covellite and malachite. Garnet, pyroxene, epidote, actinolite, tremolite, calcite and quartz are present as the gangue minerals. According to the field and microscopic studies, epidotization, chloritization, sericitization, propylitization, and argillic alterations are the most extensive alterations in the mineralized area, respectively. Based on remote sensing studies, it can be stated that carbonate, sericitic and propylitic and gossan alterations are well developed in the region and in some cases, the alteration zones in the study area overlap with together. Field studies, mineralogical and textural features show that the Saheb iron mineralization is classified as a calcium-type skarn deposit.
The Aster sensor has a unique ability to map mineral areas, which can be referred to as the ability to distinguish different types of rocks and highlight alterations in geological studies. The spectral and spatial resolution of the bands of this sensor has enabled geologists to use the Aster sensor well in studies of minerals that have outcrops and also highlight alterations. Useful studies have been conducted in the field of mapping mineral areas with outcrops, which are difficult to access and perform routine geological mapping operations in the desert field due to the presence of rugged mountains. In order to highlight alterations using the SWIR bands of the Aster sensor and image processing methods, several studies have been recorded. In this study, the remote sensing method was used for highlighting alterations for a wide area between the Indus faults in the east of the study area and the Talkhab faults in the west of the study area, and phase fusion was used, which made the size of the study area unique. In this study, two Aster images and the band ratio method, principal component analysis, and spectral angle mapper were used to determine alteration zones. The remote sensing studies conducted in the area resulted in the identification and differentiation of various types of alterations, as well as faults and fractures, which correspond with the geological map of the region. The two methods of band ratio and principal component analysis demonstrate higher accuracy compared to other methods employed in this research. Studies have shown that the Indes, Tafresh, and Talkhab faults, as the main structures of the region, play a key role in controlling and distributing hydrothermal alterations. These faults have created alteration zones along their length by creating pathways for the movement of hydrothermal fluids. In particular, the Indus fault, as one of the main faults in the region, has a significant impact on the distribution of alterations. By creating numerous fractures and joints, this fault has provided suitable conditions for the infiltration of hydrothermal fluids and the formation of alteration minerals. The relationship between faults and the ascent of hydrothermal fluids significantly affects mineral and geological alterations. Faults can create facilitating pathways for the movement of hydrothermal fluids. In general, the interaction between faults and hydrothermal fluidsleads to the formation of extensive alterations and the formation of new mineral resources.
Heavy metals are among the pollutants that cause many problems for aquatic organisms and, ultimately, for humans in aquatic ecosystems. Sediments serve as a reservoir for metal pollutants from both natural and anthropogenic sources. Therefore, the purpose of this study is to investigate the concentrations of both resistant and non-resistant forms of the metals Cu, Cd, Pb, and Hg in surface sediments at depths of 10 and 30 meters along eight transects from the fall and winter of 2018 to the spring and summer of 2019 in the southern Caspian Sea. The results showed that the mean concentration (±SE) of Cu, Pb, Cd (mg/kg dw), and Hg (µg/kg dw) in the resistant fraction were (17.08 ± 1.37), (867.80 ± 8.96), (4.82 ± 0.64), and (5.42 ± 0.05), while the non-resistant fractions were (3.09 ± 0.66), (22.80 ± 1.23), (9.70 ± 0.16), and (8.13 ± 0.05), respectively. When comparing the concentrations of non-resistant forms accessible to living organisms with international standards, it was found that the concentrations of Cu and Hg were lower than the standards, while the concentrations of Pb and Cd slightly exceeded the international standards, suggesting a man-made origin for Pb and Cd. The results of measuring heavy metals in sediments indicated that the contribution of anthropogenic sources to the origin of these metals is greater than that from natural and geochemical sources.
The Sangan mining district, the largest Fe-skarn district in Iran, is located in the northeastern part of the Alborz magmatic arc. It comprises 14 deposits (1 Gt tons and a grade of 35-60% Fe), which have an east-west trend and are divided into three parts: eastern, central and western where the Tappeh Ghermez iron deposit (A') is located in the western part. The skarnification formed near the Sarnowsar syenogranitic intrusive body, and is composed of: 1) prograde endoskarn and exoskarn zones (clinopyroxene-garnet skarn subzone) and 2) retrograde exoskarn zone (amphibole skarn subzone). Thermometry of skarnification was carried out based on the chemistry of skarn silicate minerals and their agreement with the results of microthermometry studies of fluid inclusion carried out on garnet and calcite in order to determine the physicochemical conditions and temperature of skarnification in the Tappeh Ghermez deposit. Geothermometry of the garnet-clinopyroxene pair minerals, indicated temperatures of 302 to 442°C for the prograde skarn zone. Based on the geothermometry of the calcic amphiboles in the retrograde zone, formation temperatures of 206 to 333°C have been obtained. The results of the geothermometry of the prograde and retrograde skarn zones are consistent with the results of the microthermometry of the fluid inclusions. Andradite is stable at temperatures above 430°C, even under high sulfidation conditions. At temperatures below 430°C and a relatively high fugacity of sulfur (greater than 10-6), andradite altered into calcite, quartz and pyrite. As fS2 decreases (about 10-6), such fluids form the magnetite complex. Itcan therefore be concluded that retrograde metasomatizing fluids in the Tappeh Ghermez iron skarn deposit have a sulfur fugacity of 10-6.5 and temperatures below 430°C.
The study area is located in the SaSZ, NE of Songhor city, Kermanshah Province. Based on field observations and mineralogical data, the Azizabad-Hazarkhani I-type calc-alkaline granitoid consists of granites, monzonites and diorites with small volumes of gabbroic rocks. Co-variations in major and trace elemental abundances do not indicate a continuous compositional suite and therefore do not suggest a co-magmatic origin. According to geochemical evidence, the samples are enriched in incompatible elements such as Th, Rb, La, Ce and Nd and depleted in Nb, Ti and Eu, with metaluminous affinity. These characteristics reflect the role of continental crust and crust-derived melts. Tectonic setting discrimination diagrams suggest that this complex belongs to the volcanic arc and is related to an active continental margin setting. According to the geological history of this area, it can be attributed to the subduction of Neo-Tethyan oceanic crust below the Central Iran microplate. We suggest that the Parishan and Darvazeh mantle-derived basaltic magmas may have provided the heat required for the partial melting of various source rocks, including amphibolites, meta-basites, and meta-andesites, through diffusive heating.
The study area is located in the northern margin of the Fars paleo high plateau in the Zagros fold-thrust belt. The presence of growth strata in the young Aghajari and Bakhtiari formations shows the continuation of folding until the Pliocene and Pleistocene times. The study of the geometry of the Nahreh anticline was carried out using seismic lines, geological cross-section drawing using Kink's method and field studies. The difference in the geometry of the anticline below and above the Dashtak Formation and multi axiality of anticline indicates the function of this formation as an intermediate detachment horizon. The onlapping of the Aghajari Formation on the Asmari Formation has been observed on the southern limb of the Nahreh anticline. This onlapping can be happen due to the action of the basement fault after the sedimentation of the Asmari Formation. Thus after the deposition of this Formation the Nahreh anticline was folded and then the erosion of formations older than the Aghajari Formation, occurred during the uplift of the anticline. After that, sandstone of the Aghajari Formation deposited on top of the Asmari Formation. Based on the analysis of the geometry of those onlaps investigated in the seismic lines and in the field compared with existing models, this anticline is more consistent with the limb rotation around fixed hinges, and according to the seismic line it is consistent with the hinge migration model. It is also consistent with model C of detachment folds and with an uplift rate greater than sedimentation.
The construction of geotechnical structures in sandy soils requires load bearing evaluation in undrained conditions. Undrained shear strength depends on many factors, including principal stress rotation (anisotropic behavior). However, the effect of this inclination angle (α°) is often ignored due to the difficulty in reflecting this phenomenon in laboratory research, the hollow cylinder torsional shear apparatus provides the possibility of examining the anisotropy of soils. On the other hand, most of the sand sediments contain different amounts of silt particles, which have a significant effect on the behavior of the sand, and investigating the anisotropic behavior of these mixed soils (especially in low content) has not been fully studied. This research includes 18 undrained tests using a hollow cylindrical apparatus on Firoozkuh sand with low silt content. The samples have 0, 5 and 10% silt content. Inclination angle (α°) is considered as a key parameter that shows the characteristics of anisotropy, and the values of 15, 30 and 60° are applied in the experiments. Based on the obtained results, increasing the inclination angle leads to more contractive behavior in sand. By adding a small percentage of layer, the overall structure of the sand skeleton remains constant and the samples can still be evaluated based on the general behavior of the host sand. In the samples containing 5%, reduction of contractive behavior and increase of resistance (18.5%, 12% and 7.7% for angles of 15, 30 and 60°, respectively) are observed, but with an increase of 10%, the strength is decreased (less than the host sand) and the contractive behavior is increased. In anisotropic behavior, with the increase of the inclination angle, the effect of fine grains in increasing the strength and reducing the contractive behavior of the samples as an important parameter in mixed soils is decreased.
Safe yield is the amount of water that can be extracted from an aquifer on a sustainable economic basis, considering existing legal rights, without causing significant changes in the quantity and quality of groundwater or creating other adverse effects. The Davarzan alluvial aquifer, covering an area of 703 square kilometers, is the westernmost aquifer in Khorasan Razavi Province, bordered by an ophiolite complex to the north and a salt flat to the south. Continuous groundwater extraction over the years has led to an annual water level decline of 0.36 meters, reducing the accessible and extractable water reserves in this area. Based on groundwater modeling, the safe yield, according to the Hill method, is estimated at 64.3 million cubic meters per year. This yield is 18.3% less than the current average extraction and is considered the maximum safe yield for the aquifer. Calculations estimate the renewable storage in the Davarzan aquifer at approximately 49 million cubic meters per year. Therefore, continuing the current extraction trend, which causes an annual reduction of about 13 million cubic meters, will result in continued groundwater level decline and eventual aquifer depletion in the coming years.
The Nekarood basin is located in the north of Iran and has an area of 2275 km2 . In the Nekarood Basin, the majority of limestones include thick bedded and massive limestones of Lar Formation and Cretaceous limestones, and there is also a lesser amount of limestones of the Elika, Dalichai and Ruteh Formations. Various features such as the amount of outcrop, thickness and lithological characteristics of karst rocks and their relationship to other lithologies on a regional scale are the geological controls on karst development. Among these factors, the thickness and lithology of the existing formations in the studied area are of great importance, in such a way that if the outcropping limestone is thick bedded and massive, the karstification process is very high. In order to investigate and analyze parameters such as the hydrograph and recession curve of the basin’s springs, discharge coefficient, type of flow system (conduit and diffuse), determination of the source of recharge, and water quality of the springs, physical and chemical characteristics of the springs (discharge, electrical conductivity, temperature, etc.) were analyzed. In the Nekarood basin, four karst springs, Jezi, Espeo, Kao Cheshmeh, and Senbi have relatively high discharge rates and were selected for detailed study. The analysis of temporal variations in discharge indicates that the spring discharge is significantly dependent on regional precipitation. When precipitation exceeds 15 mm, which is sufficient to recharge the aquifer, the spring water flow increases after a relatively short time delay. Furthermore, the analysis of temporal variations in electrical conductivity of the karst springs shows that electrical conductivity decreases as discharge increases. This indicates that as the karst aquifer is recharged and the proportion of recharged water increases, the dilution process reduces the dissolved salts in the aquifer water, leading to a decrease in electrical conductivity. Analysis of the recession curves of the springs revealed that the recession curve for all selected springs is multi-slope, and the discharge coefficients range from 10-3 to 10-2. Considering that the coefficient of discharge variation and the recession coefficients are relatively high in all four karst springs, it can be concluded that the dominant flow system in this karst aquifer is of the conduit-diffuse type.
