مجله یافته های نوین زمین شناسی کاربردی
پیاپی 21 (بهار و تابستان 1396)

The Sefidkuh granitoid and Shahkuh granitoid are located in southwest of Nehbandan city (South Khorasan province) and east of Lut Block. The Shahkuh granitoid rocks made of two main units by combining monzogranit-granodiorite and syenogranite and its major mineral are quartz, plagioclase, alkali-feldspar, biotite and amphibole. The Sefidkuh granitoid is contain composition range of granite (monzo and syenogranite), granodiorite and composed of the mineral quartz, plagioclase, microcline, orthose and biotite. The plagioclase composition of the Sefidkuh granitoid rocks is often andesine and sometime is albite, it is all andesine in the enclaves of Sefidkuh and Shahkuh and its granodiorite unit, and its oligoclase to andesine in Shahkuh granitoid unit. The biotite composition of Sefidkuh felsic and Shahkuh mafic enclaves is magnesium biotite type, Shahkuh granodiorite is ferrugineous biotite to magnesium and Sefidkuh granite massif and Shahkuh syenogranite unit are ferrugineous biotite and both massif are first magma types. The study of the mineral chemistry and geological masses suggest that these masses belong to calc-alkaline magma related to active continental margin. In the changes to the chondrite- normalized trace element diagrams, rock of this figures are enriched by LILE and LREE, depletion of HREE and HFSE and negative anomalies Sr, Ti, Nb, and Ba indicate that they are compatible with characteristic of the rocks depend on the active continental margin environment. The tectonic discrimination diagrams, show the dependency of shahkuh granitoid massif to the simultaneously dealing environment (syn- collision), and Shahkuh granodiorite massif with volcanic arc subduction (VAG). The petrogenetic diagrams indicated that Shahkuh granodiorite is from a source of amphibolite, Sefidkuh granitoidis from a source of metagreywackes and Shahkuh syenogranite have been achieved from a source of amphibolite to felsic pelite.

In this study, to determine the parameters of the rock mass quality Geomechanical and estimates and preliminary measures for tunnel maintenance system Pyrshryf, different methods have been used experimentally and numerically. In the case of four classification system RMR (rock mass Geomechanical classification), Q (quality index tunneling), GSI (Geological Strength Index) and RMi (rock mass index) was used. The numerical method of limit equilibrium method (software Unwedge) and finite element method (the software Phase2) were used. In order to estimate the parameters of the rock mass resistance criteria Hoek - Brown was used. The empirical analysis results showed that the first section of the tunnel to the second level, where conditions are unstable. The analysis also showed that the Unwedge instability, landslides and rock from the walls and roof of the tunnel is wedge manure. Phase2 analysis also revealed that the drilling of a step due to movements over the standards is not possible. The drill holes in two phases of the vault and Patagh was predicted. The following temporary storage system using experimental and numerical methods were proposed. Finally, it should be noted that the use of experimental and numerical methods in tunnel design is of great importance, because, in order numerical methods on the accuracy and reliability of the experimental procedures were carried out, are added. It should be noted that these methods are not mutually exclusive, but being in line with each other can lead to the development of the underground structures are designed and reliable results than when only a method is used, the provide. The use of multiple methods and new experimental results can be validated numerical methods that are usually not visible with their tolerance, will help.

The studied area of Yuzbashi-Chay located in the North West of Qazvin and stratigraphically includes Cenozoic units. Field evidence, petrological studies and geochemical data of magmatic rocks and alteration zone suggest that, this area consist of basalt, basaltic andesite, andesite, trachyandesite, trachyte, rhyodacite, dacite, tuff and dike. Plot of the major and trace elements analysis results in different discrimination diagrams indicate that these rocks formed by subduction-related magmatism in continental margins environment. Based on classification of different alteration unites; the vast parts of studied area affected by intermediate to advanced argillic-type alteration. Besides; due to the effects of alteration zones, the amount of calcium and sulfate have very high anomaly in water. Furthermore; results of water samples analysis indicate that the water hardness is greater than standard limit.The presence of hydrated aluminum potassium sulfate minerals (alunite or alum) is main potential source to produce of acidic waters. Based on drink water standard of Iran, total dissolved solids (TDS) value in alteration areas, especially in Ghazan Daghi mines, is greater than standard limit and waters of Aghche Kand alteration area are classified in toxicant water type.

Most of fluorite mines in Iran were formed in the Triassic limestones. The Kamar-Mehdi fluorite mine located in the SE of Tabas and Qarava fluorite mine in SE of Saqqez, respectively. Following the field observation, samples were selected according to the colors and transparency. Samples of Qarava mine is blue and Kamar Mahdi are purple, low pink and low green. Sample luster of the two mines are vitreous with spelendent intensity. All samples from two mines show fluorescence characteristion and aggregate (Agg) optical properties. The reflective index rate of Qarava and Kamar Mahdi samples are 1.43 and 1.42- 1.44, respectively. Kamar-Mehdi clarity grading samples are HI (Highly included), while samples Qarava is clarity grading SI (Sightly included) to HI (Highly included). Also Qarava fluorites are transparency and clarity grading higher gem quality. Because of fluorite sensitivity to heat and its low hardness, several different ways were tested to find the best cutting process and cutting tools. With respect to our lab experiences, using the 0.3 mm cutting blade in the cut step, 240 mesh disk abrasion, 360 mesh polisher to scratch-making and 900, 2000 and 5000 mesh polishers for polishing are the best tools in Cabochon and Fantasy cutting of flourite.

Abstract: Surme granitoid plutons are located southeast of Southeastern Khorasan province and 50Km in Northwestern of Nehbandan city. Basd on geological of Iran classification this pluton is located at the junction of the eastern part of Lut and Sistan suture zone. The mass is composed of a small mass number such as stocks with the general trend northwest - southeast that interrupted flysch series and outcroup to Shemshak formation? Main body of pluton is Diorite and granodiorite composition. Plagioclase, quartz, alkali feldspar, hornblende and biotite are the main minerals component of this pluton. Surme granitoid is Calc- alkaline, metaluminous to peraluminous and I type. Depletion of Nb, P, Yb,Y and Ti elements suggest that the parent magmas relate to the subduction zone setting and affected by crustal contamination.These plutons have enriched in light rare earth elements (LREE) and depleted in heavy rare earth elements (HREE) with similar patterns.These characteristics indicate the likely origin of magma that originated from the subducted oceanic crust and metasomatisem with wedge mantle and finally contamination with crustal material. According to the tectonic discrimination diagrams surme granitoid has related to the active continental crust. Surme granitoid have low Sr (135- 205ppm), Sr/Y and plot predominantly in the field of mantle- derived arc magmas (normal Calc- alkaline rocks). Variations in Th/Yb and Ta/Yb ratios indicate that the resulted magma of granitoids unites have been affected by crustal contamination en route to the surface.

Design aspects of the mining projects, including resource geological modelling, mining methodology, mineral processing and production rates have a significant impact on the project economics and overall value. To generate a resource model, typically tonnes, grade and the tonnes/grade above the cut-off are applied as the economic criterion, which are not adequate alone. Geometallurgy combines geological and metallurgical information to provide spatially-based predictive model for mineral processing plants. This novel field has been introduced to integrate the various parameters such as hardness, grindability, recovery, liberation, concentrations, mineral texture, etc. Geometallurgical modeling requires to develop matrix an x-y-z plot where two of the axes represent geological factors (e.g., rock type and alteration) and the third axis represents critical parameters (hardness, texture, liberation degree of ore, distribution of penalty elements, etc.) that plays an important role for deposit domaining. The spatial distribution of response parameters is determined based on the primary parameters, which must consider nonlinear relationships and conversion scales between the experimental, pilot or industrial modes. The proposed algorithm represents a “value chain” approach in geometallurgical model compared to the common concept of mine planning evaluations.

Hydraulic fracturing has two major applications: 1. determining the in-situ stress state of a site; 2. increasing the productivity of oil wells by propagating the existing fractures at the site. Hydraulic fracturing is used in the oil industry in order to increase the index of production and processing in wells whose efficiency has been dropped due to long-term harvest or the rocks around the well are low permeable.In this study, the Hoek triaxial cell was adapted for a laboratory modeling of hydraulic fracturing. The specimens under study are in the shape of thick-walled hollow cylinders with an external diameter of 54.7 mm, an internal diameter of 12 mm, and a height of 108 mm. These specimens were taken from the carbonate rocks of the Bangestan reservoir, located in the southwest of Iran. By using the cell, the hydraulic fracturing experiment can be modeled in the laboratory before being conducted at the site, so that a suitable pump can be selected. In all the experiments, the fractures are created with a vertical (along the sample axis) or near-vertical orientation. Borehole breakdown pressure increases with an increase in lateral stress but does not change much with a change in vertical stress.

There are three notch displacement modes including the Mode I or opening mode where the notch displacement is perpendicular to the notch front, Mode II or shear mode where notch dimensions are displaced in the notch plane and the Mode III or tear mode where the notch dimensions are displaced in the notch plane parallel to the notch front. Some application areas of rock fracture mechanics can be listed as hydraulic fracturing, rock blasting, rock cutting, mechanized drilling, rock slope stability and comminution in mineral processing. The aim of the present study was to examine the effect parameter of , modulus of elasticity and confining pressure on the mode I Critical Stress Intensity Factor (Critical SIF) using a thick-walled hollow cylindrical chalky specimen and the oil well environment was simulated in the laboratory. To perform the tests on artificial chalky specimens, two artificial symmetrical notches with certain dimensions were created in specimens with an outer diameter (OD) of 73 mm, an inner diameter (ID) of 25 mm and a height of 150 mm. A triaxial stress was applied on the specimen and the pressure required for the propagation of the artificial notches was measured. Five tests were conducted to investigate the effect of modulus of elasticity and six tests to investigate the effect of confining pressure on the mode I Critical SIF. By conducting five tests, it was concluded that with increasing modulus of elasticity, mode I Critical SIF increases and with increasing Poisson’s ratio mode I Critical SIF decreases, also, effect of modulus of elasticity on mode I Critical SIF is more. Meanwhile, it was found that the mode I Critical SIF nonlinearly increased with an increase in modulus of elasticity and it linearly increased with an increase in confining pressure.

The main aim of this research is assessing strength properties of Alvand monzogranite under different loading conditions. For this reason, at the first step, static tests under uniaxial and triaxial states were done to evaluate the effect of confining pressure on mechanical behavior of the rock. Furthermore, fatigue behavior of the rocks subjected to triaxial cyclic loading was evaluated. The fatigue tests were done in load control condition with 1Hz frequency and two states of loading including constant stress level and amplitude, and variable state of them. The results of the fatigue tests have been evaluated by fatigue damage parameters including maximum and minimum axial strain, maximum and minimum lateral strain, tangent and secant modulus, energy density and hysteresis energy. The static tests results show that confining pressure has a remarkable effect of strength and deformability properties of these rocks and has induced increasing in strength and per failure plastic phase. Elastic modulus of the rocks have been increased with increasing confining pressure in a linear function. Evaluation of the fatigue damage parameters indicated that fatigue damage process in triaxial condition shows three stages including crack initiation phase, uniform velocity phase and acceleration phase, as well. Among the fatigue damage parameters, lateral strain, secant modulus and hysteresis energy show better three-stage fatigue damage behavior.

Due to importance of groundwater resources for drinking and agricultural water supply, monitoring of quality and analysis of spatial and temporal changes of water quality is an important issue in the programming and management of water resources. In this study groundwater quality trend in Ajabshir plain was evaluated with the Spearman teas for both dry and wet seasons during the 2002-2012 time period . Water quality parameters such as SO4, Na, Cl, EC, SAR, and TDS were analyzed and quality was classified using the Wilcox diagram. The results of this study revealed that the water quality has been declined over the time period and water resources of the plain were mainly classified as inappropriate for agricultural usage. The analysis of variables trend showed a significant positive trend of SAR and EC in the Alenjiq well. Electrical conductivity has a decreasing trend in Danalo and Qobadlo wells which indicates the decreasing of the salinity in these wells. Due to the water quality and quantity decline in the plain during the past decade, watershed management practices are suggested to sustainability of the water resources.

The aim of this study is assessment the dynamics tectonic Linements and fractures related is to the Morvarid Fault, middle segment of the Main recent Fault (MRF).The MRF is a dextral strike-slip fault the with northwest-southeast trend, composed of several fault segments. The Morvarid Fault is one of the MRF segments with a .bout 30 kilometers length is located in middle part and continuation of the Sahneh fault. In this study, using remote sensing techniques and fractal analyzes, faults and Linements associated with the fault zone Morvarid examined the method used in this study, semi-automatic extraction Linements based on STA algorithm of images Landsat satellite and is shaded models. Using fractal analyzes, lineaments and faults were obtained analyzes the fractal dimension reflects the increasing the density of fractures around the fault zone MRF and the density in a process northwest southeast and parallel to the fault. Fractal dimension faults from northwest to southeast is gradually changed from 1.626 to 1.847 and this increase of fractal dimension, is also visible in the Linements from 1.811 in the northwest to 1.941 southeast will rise. In fact, factor in the rise fractal dimension in the study area, related fractures Main recent Fault, which away from this zone the faults density decreases.

The drilling fluid weight is determined according to the pressure and depth of drilling end stage fractures. The control of underground pressure of drilling fluid, as well as, transferring the solids and Cuttings of oil and gas wells are governed by drilling fluid weight. The drilling fluid weight causes to produce a pressure Equal to that of the formation and preventing the overflow of well and loss of drilling fluid. The accumulation of drilling solids and Cuttings in the fluid increase its weight resulting in slower drilling rate and decreasing the drilling bit life and undesirable fluid properties yielding mechanical and operational problems and hence more money and time consuming well driving process, while proper drilling fluid weight adjustment eliminate these problems. The combined physical and mass transfer methods results in better drilling fluid weight adjustment. In the present study the separation and improvement of drilling fluid weight in a 12 1/4" hole of a gas well in three stages was studied. First and second stage is related to change in mechanical separation and third step has been to using separators of mass transfer. In this formation, with enhancement of the fluid weight, the change in the screen (First stage) of the fluid weight at upper dolomite layer has been reduced and is kept at an optimal level. With the further enhancement of the fluid weight in the cherty zone layer, the change in screen rubber protector (second stage) caused the weight loss in this layer. Finally, the weight of the fluid is kept by centrifuge (third stage) in the mand member on 9.4 PPG proportional to the formation pressure. By continue drilling to neyriz and dashtak formations and require to higher drilling fluid weight (up to 11.5 PPG), adding weighting material is recommended.