نشریه علوم زمین خوارزمی
سال نهم شماره 1 (بهار و تابستان 1402)

The study area is located in the north of the Yusef -Kandi village, north of Lahrud, Ardabil Province (northwestern Iran). This area comprises portions of the Alborz-Azarbaijan structural zone, which together with the Little Caucasus and the highlands of southeastern Turkey have evolved due to the convergence of the Arabian and Eurasian plates during the Alpine-Himalayan orogeny. The study area includes outcrops of Eocene volcanic and volcano-sedimentary sequences which were deposited in marine to continental environments. The volcanic portion of these sequences consists of volcanoclastic rocks as well as lava flows. A few acidic volcanic rocks and ignimbrite are locally exposed in this area. The petrographic studies show that the Yusef-Khan-Kandi volcanic rocks include picrobasalt, basalt, tephrite, basanite, trachybasalt, basaltic trachyandesite, phenotephrite, tephrophenolite, trachyandesite and trachyte compositions. Phyric texture is common within the volcanic lavas. The majority of the samples show transitional to potassic trends, with only a few samples exhibiting sodic trends. The transitional trend observed in a significant number of the studied samples probably has resulted from the mingling of the sodic and potassic magmas. The Harker binary variation diagrams indicate trends that are consistent with fractional crystallization. The chondrite-normalized REE patterns and primitive mantle-normalized spider diagrams show high LREE/HREE ratios which could be explained by partial melting of an enriched mantle (including asthenospheric) or a metasomatized mantle in collisional to continental arc environments. Most of the studied volcanic rocks plot in the active continental arc or within plate domains. It seems that following the convergence between the Arabian and Eurasian plates in the Late Cretaceous, the northward subducting Neotethyan slab in the Eocene, triggered partial melting of the metasomatized subcontinental lithospheric mantle. Therefore, we suggest that the Yusef-Khan-Kandi Eocene volcanic rocks were erupted in a post-collision extensional environment.

Dynamic and static properties of the rocks are very important for designing geotechnical structures and modeling rock foundations. The main purpose of this paper is to present the regional and global relationships between the static and dynamic elasticity modulus with an experimental approach and to estimate the shear wave velocity of limestone by statistical methods and artificial neural network (ANN). For this purpose, petrographic, physical and mechanical experiments were first conducted on 80 limestone cores from the Karun 4 dam site. A database was then created using the literature data and compared with the results of this study. The results of statistical analysis show that the ratio of dynamic to static modulus of elasticity for the studied samples is 2.5. Also, the ratio of dynamic to static Poisson for these rocks was 1.41. The average value of the dynamic modulus obtained from the literature was equal to 19.90 GPa, which is less than the average value of the dynamic modulus of the present study (31.20 GPa). Due to the most accurate fit, the global relationship (R2 = 0.98, RMSE = 7.9, MAPE = 1.67) and the regional relationship (R2 = 0.96, RMSE = 5.24 MAPE = 0.91) were presented with very high accuracy between the dynamic and static modulus of elasticity. The results of artificial neural network and multivariate regression showed that estimation of shear wave velocity (Vs) based on P-wave velocity, water absorption and density is possible with high accuracy. The results showed that the ANN accuracy (R2 = 0.98, RMSE = 0.27) was higher than the multivariate linear regression (R2 = 0.86, RMSE = 0.39). The neural network also acts conservatively in predicting this variable.

The Qazikandi iron ore mineralization is located in the 70 km northwest of Zanjan and belongs to the Central Iran Zone. The rock units in the study area include Precambrian to Cenozoic formations as well as Cretaceous granite bodies. Iron mineralization in the Qazikandi area has occurred in the form of lensoid and vein in the basal part of the Barout Formation with carbonate and shale composition. The main ore minerals consist of magnetite, primary hematite, pyrite, secondary hematite and goethite. The secondary minerals which formed through supergene process and evolved during weathering of magnetite and pyrite are secondary hematite, goethite and lepidocrocite. The alteration in the study mineralization includes chloritization, epidotization, silicic, sericitization and argillic. The current research suggests that the intrusion of plutonic body with granite to quartz-monzonite composition into the Barout Formation has led to the formation of iron mineralization in the area. Due to the intrusion of the plutonic body into the shale parts of the Barout Formation, the hornfels developed and anhydrous minerals such as phlogopite were formed. Following the mineralization in this area, magnetite and then small amounts of primary hematite were formed. The mentioned alteration products developed simultaneously with this stage of mineralization. It is noteworthy that the silicic veins and veinlets which formed after mineralization, have cut the primary phases of mineralization. The field and microscopic evidence suggest that the Qazikandi ore deposit is classified as the magnesian skarn iron ore deposit.

In this study, the heterogeneity of the Sarvak reservoir in an oil field located in the Dezful Embayment was studied. The occurrence of heterogeneity is primarily attributed to various geological factors in carbonate formations, including the Sarvak Formation, resulting in significant impacts on petrophysical and other reservoir characteristics. The heterogeneity index can be calculated using conventional petrophysical logs or advanced FMI image logs from petrophysical point of view. The heterogeneity index was calculated in this study using two methods across two wells. The index was measured using conventional methods such as Dykstra Parsons coefficient, Lorenz coefficient, and coefficients of variations of porosity and permeability based on conventional logs. In contrast, the second method used FMI logs to obtain the index by calculating the sort index as a measure of heterogeneity. Based on this study, there is a high correlation coefficient between the coefficients of variations of porosity and permeability and the Lorenz coefficient with the image log index in the two studied wells (up to 60%). This study indicated the LSB2 zone has the lowest heterogeneity value while the LSG zone has the highest heterogeneity value in this field based on sort index of FMI log. The heterogeneity found in this reservoir is primarily due to diagenetic processes.

Changes in earth surface features may occur due to internal or external changes.  However, regardless of the origin of the change, detection and monitoring of these changes will contribute to environmental planning for sustainable development and optimal utilization of resources. In this sense, introducing and implementing methods that are successful in recognizing the magnitude and trend of change will be useful. For this reason, the processing of satellite images in different sciences and with different purposes has become one of the main areas of research. This study aims to identify the changing areas frequency domain using discrete fractional Fourier transform method and the optimal order of discrete fractional Fourier transform to determine the accuracy and completeness of change detection in satellite images. In this regard, due to the inability of existing software packages on detecting changes using discrete Fourier transform, a software has been developed in MATLAB environment. First, the accuracy of the output generated through developed software was evaluated on differential sample images. Then, using Landsat and Sentinel2 satellite images from different dates and finding the value of coefficient “a” in the Fourier fraction transform, different outputs were obtained. Here, the results of the change image obtained from the optimal fractional Fourier transform method were compared with the difference image.  The bands 2, 3 and 4 of Sentinel 2 did not indicate any sensitivity to changes in geological structures. However, they showed most of the changes in vegetated areas.  However, band 8 (infrared band) of this sensor not only detected changes on vegetated areas, but also revealed changes in geological structures.

Water and wind erosions are the two main factors of soil degradation. But these two processes alone, without human intervention, cause natural erosion and pose little risks to soil. Soil provides food security, preserves water resources, and affects the global climate. Soil reduces water pollutants and is also a carbon storage. The economic need for soil is greater in the world's developing countries because, in these regions, deprived farmers do not have enough resources to carry out erosion control methods. As a result, the risk of soil erosion continues to increase. Various parameters affect the erodibility of soils, including fertilizers. To investigate the effect of urea and potassium sulfate fertilizers on the soils of the Heidareh area of Hamedan, three sampling stations were selected, and then basic experiments including soil sample size, determination of Gs, Atherberg limits, pinhole test, determination of calcium carbonate percentage, determination of the organic matter, chlorine determination, sulfate content, and pH were conducted on soil samples. In this regard, the percentages of 1%, 3%, 5%, 7%, and 9% of urea fertilizer and potassium sulfate fertilizer were added separately to the soil samples of the studied stations. Then pinhole and erodibility tests were conducted using a rainfall simulator with different percentages of urea fertilizer and potassium sulfate fertilizer on soil samples of all three stations in dips of 10, 20, 30, and 40 degrees. The results of the erosion test show that with increasing the amount of fertilizers, the amount of eroded soil in all sampling stations has decreased significantly. The reason for reducing erosion can be related to increasing soil permeability and reducing runoff, by increasing the amount of fertilizers and the lack of fertilizers' effect on soil dispersion

Reconstruction of migration pathways and filling points in a field provides critical information about the location of the source kitchen and future exploration prospects in the study area. This issue is routinely performed with pyrrolic nitrogen compounds. However, these molecular indicators have encountered some limitations. The alternative solution is using crude oil maturity parameters. The reservoir filling model implies that the early oils that entered the reservoir had lower thermal maturity than the later ones. Hence, the higher-maturity oils are in the closest location to the source kitchen, and the level of maturity has a reverse relationship with the distance from the source kitchen. The signature of maturity differences is also retained after reaching the reservoir to equilibrium, and the composition becomes homogenized during geological time scales. This paper assessed the migration pathways and filling points in the Asmari reservoir from an oil field northeast of the Dezful Embayment. Four crude oil samples were collected and geochemical analyses were performed across the field. The similar geochemical signatures of the studied crude oils indicate that they were sourced from the same source kitchen and belong to the same oil family. The analyzed samples were originated from a marl source rock deposited in an open marine setting with anoxic conditions, and marine organic matter. The oleanane index higher than 20% in the studied samples implies the significant contribution of the Pabdeh Formation in charging the studied field. The thermal maturity of samples shows that all samples were generated from the source rock at the beginning of the oil window. Reconstruction of migration pathways and filling points was performed by biomarker (4-/1-MDBT) and non-biomarker (C29 αββ/(ααα+αββ)) thermal maturity parameters. The isopleth maps of both maturity parameters revealed that the Asmari reservoir was charged from the southeast. Hence, the Pabdeh source rock has a source kitchen in the northeast of the Dezful Embayment

Globally, rivers are under tremendous anthropogenic stress caused by stream fragmentation, land use changes, and regulation and water quality has been widely declined. In a review of studies, the integrity of flowing water systems largely depends on their natural dynamic characteristics, which sustain habitat. In this study, the physical and chemical factors of the Tajan River water, which is the habitat of various fishes and where the release of some economic fishes of the Caspian Sea takes place, are investigated in 7 stations during the year 2022. The results of the physical and chemical parameters such as water temperature, pH, electrical conductivity, total suspended solids, turbidity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, ammonium, nitrite, nitrate, phosphate, water quality index and comprehensive pollution index were recorded as 14.50-32.00 °C, 6.48-12.24, 562-10020 µs/cm, 2.35-185.71 mg/l, 1.8-328 NTU, 1.01-14.11, 0.58-16.05, 2.39-50.21, 0.020-1.028, 0.005-0.771, 0.49-58.56, 0.010-1.610 mg/l, 17.0-75.0 and 1.20-7.33, respectively. Based on the principal component analysis, the biochemical oxygen demand, nitrite, nitrate, and phosphate variables are in the first component, which is more important in the Tajan River. Also, based on the step-by-step regression analysis of the water quality index, the most effective variable was recorded biochemical oxygen demand, turbidity, and phosphate, and according to the comprehensive pollution index, the water quality of this river was dependent on the variables of phosphorus, phosphate, and nitrate. Finally, based on the physical and chemical parameters and various water use indicators, the Tajan River is unsuitable for fish life. Based on various indicators, station one (placed in a separate group in the cluster test) compared to other stations has more suitable conditions for releasing fish juveniles.

The infiltration of leachate resulting from waste disposal into the ground and reaching the groundwater aquifers leads to the pollution of groundwater resources. Considering the importance of water resources in the critical situation of Iran, it is necessary to carry out serious research to protect the existing resources. This research is a case study to simulate the process of leakage and transfer of leachate from landfill to groundwater and the spread and migration of four heavy metals (lead, iron, zinc and cadmium) in the unconfined alluvial aquifer of Babolsar city. The 5 ha landfill investigated in this study receives 150 tons of solid waste per day from Babolsar city. Infiltration and transfer of leachate to this aquifer is simulated using finite difference technique and MODFLOW, MT3DMS codes in GMS software. After the implementation and calibration of the quantitative model, the qualitative model was implemented for four heavy metals (lead, iron, zinc and cadmium). By applying the processes of convection, hydrodynamic dispersion and absorption, the natural cleaning potential of each element was investigated and the qualitative model of pollutant transport was calibrated and the amount and rate of absorption in the studied range were determined for each element. Based on the simulation results, the structure and geological material have had the greatest impact on the transfer of leachate from municipal solid waste in the traditional landfill in Babolsar. Due to their low permeability and high capacity to absorb contaminants, clay and organic matter in the soil of the studied area have prevented the transmission and spread of pollution plume in the alluvial aquifer of Babolsar. In order to predict the potential of natural cleaning of the aquifer in the coming years and determine the fate of these elements, the graph of changes in the concentration of these elements until they reach the standard allowed concentration was drawn with respect to time and the equation for each element was determined. The cleaning equations obtained from the qualitative model are a suitable tool for predicting the development of the pollution plume in the aquifer and determining the natural changes in the concentration of these elements with time for the optimal management of the aquifer in the hands of experts.

The Lachinag synformal anticline is located to the northwest of the Mil anticline and the western end of the Dochah Fault in northern central Iran. This synform includes the terminal members of the Qom Formation (members E and G) and the Upper Red and Pliocene conglomerates. Additionally, with an axial surface plunge from the northwest to the southeast, this fold trends toward the southeast, resulting in its asymmetric geometry. In this synform, the deformable marl and gypsum layers of the E and G members of the Qom Formation have contact with the competent conglomerate and sandstone layers from the Upper Red Formation. The juxtaposition of these layers and the occurrence of deformation phases resulted in the migration of ductile layers as well as a significant increase in the thickness of the marl and gypsum deposits of the Qom Formation (particularly in the E member). Due to the migration of these layers towards low pressure areas and their substantial thickening at the hinge of the Lachinag synformal anticline, the layers as well as the limbs of this fold were overturned. Finally, a synformal box fold was formed. Structural investigations have revealed that this fold initially formed as a result of the right-lateral strike-slip shear parallel to the Dochah Fault. This process occurred during the post-Miocene under the influence of counterclockwise left-lateral strike-slip shear forces around a pole axis at approximately 135 degrees from the north. Consequently, the fold acquired a synformal geometry. The left-lateral shear force may be due to the clockwise rotation of the South Caspian basin and the application of left-lateral shear forces on the northern parts of Central Iran, similar to what has been observed in the Kushk-e Nosrat Fault.

Ilvaite, CaFe22+Fe3+(Si2O7)O(OH), is one of the important trace minerals in the retrograde alteration stage of skarn deposits. In this contribution, by using microscopic evidence, X-ray diffraction (XRD) and electron microprobe analysis (EPMA), the crystallographic characteristics, crystal chemistry and thermodynamic conditions of ilvaite have been investigated in the formation of skarn deposits. The Gholamabad iron skarn deposit (1.3 Mt with an average grade of 37.2% FeO) is located 30 km SW of Dehgolan, North Sanandaj-Sirjan Zone (N-SaSZ). Skarn formation has occurred in this deposit at the contact of alkali granite porphyry (Upper Jurassic) and tuffaceous siltstone sequence (Triassic-Jurassic), which was accompanied by progressive alteration of brown andradite-hedenbergite near the intrusive body and retrograde alteration of epidote-actinolite-calcite in the vicinity of volcanic rocks. Ilvaite with empirical formula, Ca0.90Fe2+1.88Fe3+0.98Al0.04Mn0.04Mg0.02Si2.14O8(OH), formed from the reaction of andradite, magnetite, and quartz minerals during retrograde alteration stage (temperature 400 to 470 °C and ∆logfO2(HM) between -4.2 and -4.0). Then, in the final stage of retrograde alteration, with increasing XCO2 activity (0.05 to 0.005) and decreasing oxygen content (∆logfO2(HM) < -4.5), ilvaite has been decomposed to the magnetite, calcite, and ferroactinolite assemblage at temperature 270 to 350 °C. According to the results of EPMA, the high ratio of Fe2+/ Fe3+ (avg.= 1.90) and low content of Mn2+ (<0.05 assumed six cation sum) in the ilvaite of Gholamabad deposit indicates that it belongs to Fe skarn deposits, which is different from other skarn systems. In general, although ilvaite is a trace mineral in most skarn systems, the results of this approach show that the composition and thermodynamics of ilvaite can be used to distinguish different types of skarn deposits and the evolution of geochemical-skarnification processes.

The Oligo-Miocene Asmari Formation is one of the most important hydrocarbon reservoirs in the Zagros sedimentary basin, especially in the Dezful depression. The Formation in most of the oil fields of the Dezful depression consists of a mixed carbonate-siliciclastic sequence. In this study, the relationship between sedimentary sequences and diagenetic processes with reservoir zones is considered. For this purpose, sedimentological data and petrophysical logs of a key well were used. Based on microscopic studies on the core thin sections, four detrital petrofacies and eight carbonate microfacies were identified that were deposited in four facies belts, including open marine, shoal, lagoon, and tidal flat environments, related to a homoclinal ramp. In addition, six depositional sequences (third order) were identified by facies analysis and well logs. Reservoir properties have been increased by dissolution and dolomitization with pore space expansion, while being decreased by cementation and compaction. The Asmari Formation in the investigated well is subdivided into eight reservoir zones based on sedimentary characteristics and petrophysical properties. The coincidence of the facies boundaries with the reservoir zone boundaries in most cases shows that the changes in the reservoir properties are mainly related to the changes in the sea level. This is well-known in the lower zones