مجله یافته های نوین زمین شناسی کاربردی
پیاپی 27 (بهار و تابستان 1399)

Considering the diverse climatic conditions of Iran with a varying from hot and dry and also coastal areas it can be seen that salt weathering is one of the most important agents affecting on the durability of stones used as wall cladding of the building. As a result it is necessary that durability of stones be assessed and the most resistance and appropriate those be selected for use as wall cladding of the buildings. In this research, durability of six samples of travertines from Azarshahr and Mahallat areas against salt weathering were investigated. For this purpose, salt weathering test at sulfate sodium (Na2SO4) up to 60 cycles was carried out and, after every 5 cycles, changes in the samples appearance (color, efflorescence, chemical and physical decay), mechanical properties (point load strength, Brazilian tensile strength and P-wave velocity) and Dry Weight Loss of samples were monitoring and measured. The results indicated that changes in samples appearance including the color, efflorescence, chemical and physical decay due to criteria of measure those is qualitative, can not to be appropriate for assessment of samples durability against salt weathering. Moreover, results show in among parameters that criteria of measure those is quantitative, Brazilian tensile strength and P-wave velocity are more reliable in compare with point load strength and Dry Weight Loss for assessment of samples durability. Also, macroscopic monitoring of samples appearance against salt weathering show that petrological properties have major role in chemical and physical decay and therefore their durability.

Today, the growing population on the one hand, and the limitation of fresh water resources, on the other hand, have led to an assessment of water quality in terms of quality and quantity, especially in arid areas, in a special place in groundwater studies. So that the supply of water needed for drinking with proper quality and without any kind of pollution, has become a human challenge. One of the indicators for assessing water quality is the concentration of the main ions in water. The concentration limit for these ions in drinking water has been determined by the World Health Organization (WHO). One of the most commonly used methods for assessing drinking water quality is the Schuler diagram, which allows water to be checked at a specific point in the area. Hence, the five selected samples representing the entire aquifer are in good quality. But, in order to investigate the spatial variations in drinking water quality across the entire aquifer area, the Groundwater Quality Index (GQI), presented in 2007 by Babyker et al., Was also used. The results of this study showed a value of 74 to 95 percent, the groundwater of the studied plain has good drinking quality standards.

Gash metamorphic complex is cropped out in the Talesh Mountain (Western Alborz). According to the field and microscopic evidences, there are two generations of granite in the Gash metamorphic complex. The first generation of granite (G1) is medium grained and light gray and displays mylonitic fabric. The second generation (G2), contains coarse leucogranites that has been injected into the first generation of granite and metapelitic rocks. Quartz, plagioclase, K-feldspar and biotite are the rock forming minerals of the first generation granite. The main minerals of the second generation granite are quartz, K-feldspar and plagioclase. Tourmaline, garnet and sillimanite are accessory minerals. Geochemical and mineralogical evidences indicating that the precursor of first and second generation of granites are I- and S-type, respectively. There is considerable compositional similarity particularly between the second generation granite and leucosome of the adjoining migmatites and Himalayan leucogranites that are indicator of collision setting. The prolonged geological history of Paleo-Tethys closure episode was resulted in successive generations of granitization in the continental active margin from Carboniferous to Upper Triassic. Probably, during subduction and prior to continental collision stage, the first generation of granites have been formed in the edge of Turan block. The final stage of Paleo-Tethys vanishing has taken place as a consequence of collision between Alborz block and southern margin of Eurasia during Eo-Cimmerian orogeny and terminated with the formation of metapelitic of Gash complex in the middle to lower depth of the continental collision setting and production of the second generation of granitization.

Weathering is one of the important and controller factors of the physical and mechanical properties of peridotites. The engineering properties of rocks undergo significant changes due to the weathering process. Weathering depends on the mineralogical composition and peridotite texture properties. In this research, the effects of mineralogical characteristics of Harsin peridotites in Kermanshah province were studied. The studies Contains Field surveys and laboratory studies. In vitro studies, thin sections of peridotites were first considered with different weathering conditions. Then, by performing physical and mechanical tests, specific gravity, unit weight, moisture content and porosity were determined, respectively. In the following, the values of unixial compressive strength, Young's modulus, point-load index and hardness of samples were calculated. In this study, due to the mineralogical characteristics and the degree of weathering of the peridotites, based on the degree of serpentinization of the rock in each stage of weathering, the effect of these factors on the engineering properties of the rock was evaluated. By using Excel 2013 regression correlation software the relationship between weathering, mineralogy and texture properties was determined by geological characteristics of peridotite engineering. These relationships have been linear functions. Also, F, t tests confirmed the 95% confidence level of proposed experimental relationships. Based on the results, the highest correlation 0.95, is founded between the point-load indexes with the index of micro-cracks. The results obtained in this study showed that the importance of texture properties is more important than mineralogical properties in determining the geological engineering properties of rock. This means that the characteristics of kernel such as shape and size, type of contact, degree of weathering, and the index of micro-crack shave an important effect on the geological characteristics of the engineering of peridotite rocks.

In this study, analytical Duncan-Fama (DFM) and numerical finite difference (FDM) methods based on convergence-confinement (CCM) procedure was used to deformation analyses, stress field and plastic zone expansion estimation for rock mass of tunnel Golab 2 which simulated by RocSupport and FLAC2D softwares. The CCM approach utilizes ground response curves (GRC), longitudinal deformation profile (LDP), and support characteristic curves (SCC) to evaluate tunnel wall displacements. The simulation is implemented for the most critical tunnel zones (zones 2 and 10 out of 15 zones) which generally consisting of shale with sandstone and siltstone geological units. These zones have variable features and highly tectonised. The geotechnical investigation results are shown that these zones (especially zone 10) have lowest strength mechanical parameters which main focus of this study is on these zones. Based on the analytical and numerical models were obtained for the 4 classes by CCM (GRC-SCC) curves for these intervals, it is found that these zones are under internal pressure about 7.56 and 4.18 MPa, respectively. Also, produce a plastic zone of about 2.85 and 2.88 meters. As results implementing maintenance structure with a permitted 10 mm displacement can reduce the plastic zone to 2.43 and 2.30 meters in the studied zones as well as provided structural stability in 15 mm. In conditional simulation, although the numerical method rather than analytical method is more falls and followed greater rigidity support system, but the CCM process is better suited to environmental conditions. On the other hand, by studying LDP-based behavioral diagrams, the estimated displacement is approximately the same for the short-term, mid-term, and long-term intervals. As evaluating the in-situ stress field for zones 2 and 10, it was found that the stress field variations in zone 10 was sudden but zone 2 was followed by continuous deformation changes.

The quality of water varies according to the length of the path and the frequency of liquidation in the course of the movement. Therefore, statistical and graphical methods can help administrators by intermediate location management for water resources in each region. The purpose of this research is to study the quality of groundwater and surface water of Al-Shate plain for drinking and farming. For this purpose, 18 sampling points from 2007 to 2017 were used and parameters EC, TDS, TH, pH, Hco3, chlorine, sodium, SAR and magnesium were used. The ANOVA and the mean comparison of two independent samples were used to compare the treatments. The irrigation water classification was also identified with the help of the Wilcox chart. The results of analysis of variance showed that there is a significant difference between the parameters of sodium, acidity, bicarbonate and SAR in two stations of Kahriz and Shahr during ten years. Also, all samples are suitable for irrigation quality for agricultural use. The evaluation of methods for linking two important indicators of groundwater quality including electrical conductivity and sodium absorption ratio showed that IDW methods with a second power with Mean Error and Mean Squared Error were for EC 0.03 and 0.17 and for SAR 0.001 and 0.001 are the best. Changes in two important indicators of groundwater quality, including electrical conductivity and sodium absorption ratio by Kriging method, showed no change in the beginning and the end of the period.

In the case of explosions and fires, the rocks undergo cycles of heating and cooling, that is, they are exposed to considerable heat first and then cooled after extinguishing the fire. The purpose of this paper is to study how the temperature in a heating-cooling cycle can affect the physical and mechanical properties of fiber concrete (FC). During the heating phase in a heating-cooling cycle, experiments were performed on samples that were initially exposed to temperatures of 300, 500 and 700 °C and then cooled gradually to ambient temperature. At the same time, a series of experiments were performed on samples that were not exposed to a heating-cooling cycle. For this purpose, non-fiber concrete (NFC), polypropylene fiber concrete (PFC) and glass fiber concrete (GFC) samples were fabricated. The effect of the heating-cooling process on effective porosity, longitudinal waves velocity, uniaxial compressive strength, and tensile strength of PFC and GFC samples were investigated and compared with the NFC samples. The results show that fiber concrete containing 0.5% glass fiber has the highest tensile and compressive strength at 300 ° C. Fiber concrete containing 0.5% polypropylene fiber at 500 ° C has the highest compressive strength and at 700 ° C has the highest tensile strength among all types of non-fiber and fiber concrete with different percentages of fibers.

The huge production of municipal solid wastes is one of the most important problems in modern societies. Improper management of the produced wastes may result in environmental pollution and is a threat to human health. Site selection for municipal waste disposal is considered as an important stage in waste management. Geological, environmental, social and economic considerations are the most important parameters which influence the selection of proper waste disposal sites. In the present study, site selection for the disposal of municipal solid wastes produced in Kangavar city, Eastern Kermanshah, has been investigated. For this purpose, geological (i.e. lithology, seismology, faults, soil texture and soil erosion potential), environmental (i.e. precipitation, distance from rivers, water table depth, and prevailing wind direction), and social-economical (i.e. distance from the roads, land use, rural and urban population centers, slope and elevation) factors were considered as the most significant factors and then, fourteen data layers were created in GIS software and the weight of each layer was determined using Analytical Hierarchy Process (AHP). After the combination of GIS maps and AHP data and omitting the forbidden areas, the area was classified into four classes (i.e. suitable, relatively suitable, relatively unsuitable, and unsuitable areas) for waste disposal. On the basis of geological, environmental, and social-economical criteria and after field surveys, the best site for waste disposal was selected at 16 Km south of the Kangavar city.

Considering the important role of landslide in watersheds, the present study has investigated the effective factors in landslide occurrence in Ardal watershed, Chaharmahal Bakhtiari province. In this research, landslide inventory map was prepared using satellite images, aerial photos and field investigation. At the same time, maps of the effective factors in the landslide event were prepared. Slope, direction of gradient, height, lithology, rainfall, distance from fault, river density, distance from road and land use were selected as factors affecting landslide occurrence. Logistic regression method has been used in GIS environment to prepare landslide sensitivity map. Using these factors and land inventory map, landslide susceptibility and the significance of each selected factor for landslide occurrence in the area, were identified by logistic regression method. The results showed that "distance from the river", "land use" and lithology are considered as the most important factors influencing the landslide occurrence in the region. .

Sediment gravity flows are categorized based on combination of five parameters: sediment concentration, sediment-support mechanism, flow state (laminar or turbulent) and rheology (flow type and its deformation). Except for rheology, all of these parameters change gradationally from one member to another. Therefore, rheological classification of sediment gravity flows should be the most straightforward and the least controversial. These flows can be either Newtonian (i.e., turbidity currents), or non-Newtonian (i.e., debris flows). However, identification of flow rheology by examining the deposits may not be easy. Although we may confidently identify some rocks as turbidites and others as debrites, there are some transitional deposits, here called densites. Densites share both the characteristics of turbidites and debrites. Densites are the deposits of dense flows, which are rheologically stratified flows having a composite rheology of Newtonian fluids and non-Newtonian fluids. The term gravite is proposed for deposits of any kind of sediment gravity flow, irrespective of their depositional environment. Nowadays, turbidity currents only for sediment gravity flows with Newtonian rheology. These types of currents with Newtonian rheology, unlike other currents, should produce a diagnostic distribution grading (due to differential grain settling) from the bottom to the top of the deposits (i.e., Bouma sequence). Turbidite systems are classified based on grain size (mud-rich, mud/sand-rich, sand-rich and gravel-rich), sediment composition (calciturbidite and siliciclastic turbidite) and feeder system) submarine fan with point source, ramp with multiple source and slope apron with linear source). Fine-grained, mud-rich turbidite systems mainly occur in basins with a large fluvial input. The calciturbidites and siliciclastic turbidites in Iran can be named Pabdeh and Sarvak Formations (Zagros Basin), terrigenous part of Amiran Formation and Miocene siliciclastic deposits, respectively.

The accurate determine of uniaxial compressive strength (UCS) and modulus of elasticity (E) using laboratory methods requires substantial time and cost. To overcome these difficult, development of predictive empirical equations to estimate the UCS and E of rocks is very important in rock engineering. This study deals with the prediction of UCS and E of sandstones from petrographic characteristics using multivariable linear regression analysis (MLR). For this purpose, 20 rock blocks were collected from sandstones in different locations of Upper Red Formation in southwestern Qom. Samples were subjected to petrographic examination, which included the observation of 16 parameters and modal analysis. The specimens were also tested to determine the uniaxial compressive strength, modulus of elasticity, porosity, and dry density. Based on the results of statistical analysis, multiple predictive equations were developed to estimate the mechanical properties using petrographic characteristics. The performance of developed equations was assessed using R, RMSE and VAF. Based on the results, it was observed that the proposed equations have a good performance in predicting the UCS and E.

Ophiolite outcrops and ophiolite clusters have spread widely in Iran. Ophiolite is referred to as a collection of mafic and voltramaphic rocks, which may be ordered or layered or interconnected by tensile stresses. Ophiolite; ophiolite complex, ophiolite series, was finally told that the color combination of the words' color combination (Kalrd melange) more applications. Due to the variety of research done in this field and the lack of a review article, a new research work has been done. The purpose of this article is to review the geochemistry and tectonic environment of the formation of ophiolitic zones of Iran. The results of this research show that in terms of dispersion, Iranian ophiolites are a type of melange that can be distinguished in the two groups of Zagros radiolarite ophiolite strips and Central Iranian tape. In the southwest of Zagros, there are two separate parts, called Ophiolite, Kermanshah and Nayriz. Central ophiolites, which are named after the submarine strips of central central (Sabzevar, north of Torbat Heydarieh, south of Birjand) and east of central Iran (Mako-Khoy, northern Makran and northern Nain) due to subduction, part of the upper mantle and the crust The ocean is left in the form of an ophiolite melange. Also, the results of many geochemical studies on Iranian ophiolites have shown the dependence of Mid-ocean ridge basalts (MORB) and island arc tholeiitic (IAT. Both groups of subalkaline and alkaline basalts have been identified in the ophiolites of Kermanshah. In the ophiolites of Neyriz and Babak, several types of basalt that have IAT attributes have been identified and reported. The chemical composition of Sabzevar ophiolite also shows the geochemical characteristics of the IAT type. Two types of basaltic lava have also been identified in the Ophiolite of the Ziarat (Bakhtar Makran).