مجله یافته های نوین زمین شناسی کاربردی
پیاپی 30 (پاییز و زمستان 1400)

In recent years, groundwater pollution has been raised as an important environmental issue in developed and developing countries due to changing land use patterns. Among the many groundwater pollutants, we can mention the leachate produced from waste or municipal waste landfill, which poses many environmental hazards due to its toxicity and high durability in the environment. Kermanshah is the ninth most populous city and one of the metropolises of Iran, the center of which is Kermanshah and according to the 2016 census has a population of 946,651 people. Due to high population growth and immigration, it has led to an unprecedented increase in population that is not within the capacity of the city's infrastructure. As a result, along with many environmental problems in this city, it faces serious problems in terms of waste collection and disposal because the amount of waste production per citizen of Kermanshah is on average 750 to 900 grams per day, which is twice the global average. This waste is accumulated in the southern part of Kermanshah city and at a distance of about 15 km from it on the northern slope of Kuh-e Sefid. In this study, according to the geomorphological features of the region, the pollution of groundwater resources in the downstream areas of the landfill in Sarabghanbar of Kermanshah (Kermanshah city) has been investigated in GMS software environment and MODFLOW analytical code. In this study, first the geomorphological map of Kermanshah city in order to identify groundwater, soil, and slope and land type has been drawn. This map shows that the uneven erosion plain of the southern half of the city, due to the landfill of Kermanshah, can provide a source of pollution for Sarabghanbar springs. The groundwater level map shows the direction of water flow in this area from south and southeast to the center of the plain and then north and northeast. Landfill construction site, and groundwater flow direction are the main factors in the spread of pollution. Studies show that during the study period, the groundwater level in drought periods is constantly declining and its rate of rise in wet periods is always less than its rate of decline in dry periods. The results of MT3DMS quality model showed that in order to solve the problem of infiltration of landfill pollution in the groundwater network, among the several solutions that can be offered to water resource executives, one is blocking the border power supply of the plain and the other is controlling and preventing excessive drop. Groundwater level.

The aim of this study was to investigate the electrical conductivity of groundwater due to physical and chemical parameters of water using ANFIS-FCM method in Azarshahr, Ajabshir and Maragheh study areas of Urmia Lake catchment area. To achieve this goal, 82 water samples were taken from wells and springs in the plains and the data were chemically analyzed in the laboratory. Descriptive statistical data and correlation matrix of the studied parameters were obtained using SPSS software. By forming the correlation matrix, it was found that the four salinity parameters, soluble oxygen (DO), total soluble solids (TDS) and pH, have the highest correlation with electrical conductivity (EC) compared to other existing parameters. Therefore, the inputs of the model included the four mentioned parameters and the output was selected according to the purpose of the research, electrical conductivity.  After standardization, the data entered the MATLAB environment and using ANFIS-FCM method, the electrical conductivity of groundwater was predicted. In this method, 80% of the data (66 samples) were randomly selected for the training data set and 20% of the data (16 samples) were randomly selected for the test data set. For ANFIS-FCM training data set, R2, RMSE and VAF values were 0.9999, 0.0032399 and 0.99993, respectively, and also for ANFIS-FCM test data set, R2, RMSE and VAF values were 0.9998, respectively, 0.0029949 and 0.99972 were obtained. Using the results of this model, it was found that the estimated electrical conductivity in the studied areas had a very good accuracy and high correlation with the measured values. As a result, the ANFIS-FCM intelligent method is an effective, efficient and accurate way to estimate the physical and chemical parameters of water.

Brittleness is one of the most important mechanical properties of rock which has a widespread application in underground constructs drilling like tunnel drilling. Although many method have been introduced for estimating brittleness, no standard has been mentioned for measuring brittleness. In this research, experiments for determining   brittleness of S20 along with petrographic (main mineral percentage), physical (dry density, saturation density, porosity and water absorption percentage), mechanical (uniaxial compressive strength, Brazilian tensile strength , point load test) and dynamic properties (pressure and shear wave velocity) in the two states of dry and saturated were performed on 19 test samples of igneous rocks (granite, granodiorite and dacite) selected from Sangan iron ore mine in khaf. Statistical analysis of the results shows that brittleness of samples increases with increasing alkali feldspar and quartz and also reducing plagioclase. Also existence of micro particles and carbonate veins decreases strength and increases the brittleness of rock and facilitate excavatability of samples which is more prominent in saturated state. There is an inverse relationship between S20 brittleness and the brittleness indices, and as the value of S20   brittleness increases, the value of brittleness indices decrease. The relationship between S20 brittleness and brittleness indices B3 and B4 has the highest coefficient of determination. As a result, it can be said that the brittleness measured in the laboratory can be more realistic in expressing the brittleness of rocks.

Negin Park area in the east of Tabriz city has an area of about 110 hectares with topography of the hills and valleys. Therefore, during urbanization, the upper part of the hills is cut and is cast in valleys and low lands. Marl layers are also widely spread in this area. The development of fill soils and the presence of marl layers that have a low geotechnical strength and stability are the main challenges in implementing deep excavation projects for building construction in this area. Marl layers are seen in yellow, green and gray colors. Investigating of the subject, by examining old aerial photographs and geological maps, as well as field studies and visits to deep excavation projects and collecting information on excavations in the region, properly paid. From 3 deep excavation projects has been visited and 25 boreholes information have been collected. The results of the studies are presented as a map of the development of fill and marl soils. About 28% of the area is covered by fill soils with a thickness of more than 2 meters and also about 35% with marly soils. The depth of groundwater table in this area varies from 5 to 20 meters. In the dry marl layers, the strength and stability of to deep excavation walls are suitable, but the stability is strongly reduced of the saturation layers, soil nailing and anchors are difficult to use. Due to the type of underground layers, the depth of the groundwater table and the depth of excavation, in this area are using various stabilization methods, such as the retaining walls, piles and anchors, soil nailing and anchors with shotcrete. The efficiency of nails and anchores is facing with problems due to creep phenomena.

Hydrocarbon explorations usually are performed based on seismic inversion techniques in which there exists computational complexity. Therefore, application of simpler methods such as probabilistic neural network could be considered to decrease uncertainties of the results. The present research used a probabilistic neural network to characterize the sand reservoir of F3 block in North Sea. This algorithm applied the seismic attributes of energy, similarity and instantaneous amplitude as input parameters to estimate porosity distribution of the F3 reservoir. Calculating the likelihood probability is dependent on the smoothing parameter. Therefore, the cross validation technique was used to determine the smoothing parameter that equals to 0.21. This paper considered 16 porosity classes from 0.22 to 0.3 as output of probabilistic algorithm. This algorithm calculated the posterior probability for every point in reservoir to determine the class of each point. The maximum posterior probability was selected as the final output. The obtained results were compared with the linear equation driven regression model for acoustic impedance and porosity values. The comparison showed that the developed network could detect gas-bearing region. Also, the confusion matrix was used to validate the results and the total accuracy parameter was calculated as 0.7587 and 0.4623 for probabilistic neural network and linear regression, respectively. Therefore, Bayesian neural network could be introduced as an effective tool to explore the hydrocarbon-bearin layers because of computational complexity of seismic inversion techniques.

In this paper, a method based on the 2D Marquardt inverse modeling of anticlinal and synclinal structures using the gravity field data is introduced and the density contrast of the difference depths of the earth is computed based on a parabolic density function (PDF). The normal and inverted isosceles triangular models are generally used to describe the geometries of these structures in analyzing gravity anomalies. In the absence of known geology, it may not be possible to isolate completely the gravity signature due to a geological structure from the regional gravity background. In this paper a computer program solves three different parameters of the structure, z1, z2 and i, in addition to estimating two coefficients of regional gravity anomaly. The modeling process begins with computing the theoretical gravity anomaly of an anticline or syncline prototype, defined by approximate shape parameters in each case that can be attained from known geology. The program reduces the error between the observed gravity anomaly and the estimated gravity anomaly by improving the initial parameters of the model during repetition until the misfit function falls below a predefined allowable error or the damping factor acquires a large value or the specified number of iterations is completed. The efficiency of the algorithm is illustrated with a set of synthetic gravity anomalies over an anticlinal and a synclinal structure both with and without regional background, further, the code is exemplified with the gravity data from Kerend region, Iran. The target of gravity survey studies is determination the limits and depth values of anticlinal structures as a probable hydrocarbon traps. The results show the top depth of the anticlinal about 2800 m, the bottom depth of the anticlinal about 4200 m and the bottom depth of the synclinal about 5600 m.

Previous studies have shown that moisture has a special effect on the static properties (uniaxial compressive strength (UCS) and elastic modulus (Es) of the rock. In this study, thin section, X-ray diffraction (XRD), porosity, UCS and Es, point load index, and Brazilian tensile strength of the limestone specimens were determined in Khersan 2 dam site, in south west of Iran. Then, using artificial neural network and simple regression, the effect of dry point load index, dry and saturated tensile strength, and porosity on UCS, Es were assessed. Microscopic studies of the samples showed that calcite is the main mineral and samples classified from the Mudstone to the Grainstone. The effect of water on the static properties showed that prediction models in dry conditions are more accurate. Calibration of the relationships presented by previous researchers based on the experimental results of this study and using the criteria of coefficient of determination and root mean square error (RMSE) showed that most of the relationships can be used to estimate the properties of Asmari limestone. Also, investigation of heteroscedasticity graphs of residual variance at predicted levels, determination coefficient and RMSE of the methods showed that the neural network has higher accuracy than simple regression. As compared to the regression method, the neural network is conservative in estimating these properties.

Loose soils (CL-ML silty clays) are one of the most important problematic soils that have caused various geological hazards in the world, especially in Iran. Therefore, in order to reduce the geological hazards of such soils, it is necessary to make changes in their geotechnical properties. The aim of the present study is to investigate the effect of nano-illite on the geotechnical properties of loess soil including Atterberg limits and compressibility. For this purpose, a loose soil sample was prepared from Gonbad Kavous city of Golestan province and geotechnical tests including Atterberg limits and compaction were performed on it. Tests were performed on soil samples with percentages of 0.5, 1, 1.5, 2, 3, 4, 5 and 8 nano-ilite. The results show that in the Atterberg limits test, the plastic limit is from 19% (without nano-illite) to 36% (in 8% nano-illite) and the liquid limit is from 26% (without nano-illite) to 40% (with 8% nano-illite) have increased. Also, in the compaction test, the maximum dry unit weight increased from 1.97 g /cm3 (without nano-illite) to 1.99 g /cm3 (in 2% nano-illite) and then decrease to 1.96 g /cm3 (in 4% nano-illite), while the optimum moisture has continuously increased from 12 to 12.9% in 0 to 4% nano-illite, respectively.

Determination of brittleness and geomechanical parameters, especially uniaxial compressive strength (UCS) and Young's modulus (ES), is required for designing and various applications of rock engineering. Evaluation of these parameters is a time-consuming, tedious and costly process requiring the preparation of suitable rock cores, therefore, experimental correlations are being used to predict the properties of rocks. In this study, to predict brittleness and determining the experimental correlation between physical and mechanical parameters of Talezang limestone formation, 74 rock core samples obtaining from 10 geotechnical boreholes with a depth of 70 m in the basement of Hawasan dam in dry and saturated conditions were used. After analyzing the descriptive statistics of the samples in SPSS 25 software, simple regression correlation relationships were approached based on the best fit between physical and mechanical parameters and according to multiple regression model, an experimental equation with coefficient of determination (R2 = 96) was applied to predict brittleness index of Talezang limestone. Finally, the obtained experimental equation based on the values of uniaxial compressive strength (UCS), Brazilian tensile strength (BTS) and compressive wave velocity (Vp) and statistical relationships between physical and mechanical parameters for determining the brittleness index (BI) in saturated conditions was compared with previous relationships in the literature. The results show that the accuracy of the statistical relationships presented is consistent with previous relationships.

This study aimed to investigate the mineralization potential of such metals as copper, gold and molybdenum at the Miyaneh's zone level (focusing on the western and eastern-northeastern areas). For this purpose, the proposed approach was to use direct geological studies and to take samples on the mineralization of these metals. Indirect data (telemetry) were used to discuss mineralization potentiality. In this connection, satellite and telemetry data were used for mineralization and alteration in the study area as the results were classified. At this stage, such software as Envi, Arc GIS and Image analyzer were used. The findings revealed that the Miyaneh's eastern zone was not found to generate any metal potential. In the western part of the said zone, the situation of metal mineralization is different, because intrusive, semi-deep and existing igneous rocks are widely seen in this area which are often exposed to the alteration phenomenon. These conditions have led to the metal mineralization in some western zones of the city. The most important mineralization processes include the presence of gold mineralization in siliceous veinlet, the presence of molybdenum mineralization in the form of veinlets and the presence of iron mineralization in the form of goethite and hematite.

Groundwater in arid and semi-arid areas is one of the important sources for various uses that undergo quantitative changes. One of these areas is Firoozabad plain in the west of Fars province, whose groundwater is the main source of agricultural and drinking water. In this paper ,quantitative change in groundwater level of Firoozabad plain, which is one of the agricultural  hubs of iran,were investigated by Mann-Kendal l test.The result showed that  according to the unit hydrograph of Firoozabad plain in the statistical period of !992-2011in the east and west of the river, the general trend of water table changes has a continuous ang significant decline,so that in the east of the plain more than 21  Meters and in the west 20.83meters the groundwater level has dropped. However, due to heavy rainfall(678mm) in 2004, the map of groundwater depth changes in the aquifer in 2001-2006shows less decline. Changes in the unit hydrograph of Firoozabad plain for the period 2006-2011 show a sharp drop in groundwater level, so that it can be seen in everywhere of aquifer drop.Groundwater balance of the aquifer of this plain in the statistical period indicate that the change in the volume  of the  aquifer reserve due to additional harvest(discharge) during the statistical period of 17.5million cubic meters is negative anf is the main cause of water table decline.This discharge was mainly provided by exploitation wells.Due to the role of surrounding geological formations in feeding the aquifer of Firoozabad plain,it is not possible to use this resource to compensate for water shortage in the future. Therefore, other water resources in the region, including water transfer from Tangab and Hayqar dams, should be considered. In general, in the margins of the heights, the water source depth decreases more and decreases towards the center of the plain.

The aim of this study is to evaluate suitability of groundwater for irrigation purposes in Urmia alluvial plain, West Azerbaijan, Iran; where agriculture activities are dependent on groundwater because of increasing drought trend in Lake Urmia. Fifty-nine water samples from groundwater were selected during dry season in 2018 and analyzed for water quality parameters. The present study was carried out to investigate the spatial variability of water quality indices (PI, MAR, SAR, RSC, LSI, KR and %Na) by geo-statistical methods to determine suitable areas for irrigation. Electrical conductivity (EC), pH, calcium, sodium, chloride, sulfate, potassium and TDS concentrations were in permissible limit, while %8.5 and %17 of groundwater wells; in bicarbonate and magnesium, respectively; were higher than acceptable limit within prescribed limits as FAO (1994) for irrigation purpose. The calculated SAR values suggested excellent quality for irrigation. The values of PI and %Na suggest that the groundwater of study area is suitable for irrigation purpose. It shows that concentrations of MAR in %18.6 of wells and RSC values in three of samples, are lower than the permissible limit; Whereas computed values of LSI and KR indicate unsuitable groundwater of study area. The spatial distribution maps of groundwater quality indicated that the central of Urmia plain is the most suitable zone for irrigation purposes.