مجله یافته های نوین زمین شناسی کاربردی
پیاپی 23 (بهار و تابستان 1397)

Nourabad-Harsin plagiogranites are the part of ophiolite complex in the Zagros zone located between sheeted dikes and gabbroic rocks. Lithologically, they include tonalite and trondhjemite. Minearals in these rocks are quartz, plagioclase, alkali feldspar, amphibole and biotite. Micrographic, granular, granophyre and myrmekite are the most common texture in these rocks. Microprobe analyses show that plagioclases have albite composition and amphiboles belong to calcic series and magnesiohornblende to actinolite subgroup. The geochemistry studies reveal that the parent magma of these rocks is of M type, calc-alkaline, low K, metalumine and from oceanic plagiogaranites which developed in Supra-subduction zone. Chondrite, MORB and Primitive mantle-normalized REE patterns show an enrichmentin LREE along with an almost flat pattern of HREE and negative Eu anomalies. It appears that these rocks are resulted from the magma generated by the subduction of the Neotethys oceanic plate and fractional crystallization at higher levels of sequence and its emplacement due to the tectonic movements in the region.

Geotourism is one of the main factors of sustainable economic, social and cultural development in an area that enhances handicrafts and employment in different fields directly and indirectly. The city of Hamedan has an area of 4084 square kilometers. In this research, the main geotourism attraction is introduced as Alvand northern hillside. The Alvand mountain range is divided into the northern and southern hillsides. The Alvand Mountain with its northwest to the southeast direction has divided Hamedan province into the northern and southern divisions. In this mountain, deep and lush valleys (such as Heydareh and Muradbeik valleys), springs (such as Howz-e-Nabi and Cheshmeh Behesht), meadows (such as Meidan Mishan, Takhte-e-Nadir, Takhte-e-Rostam and Takhte-e-Kuchak) and numerous peaks are formed. Alvand to Yakhchal peaks which is the highest peaks of this mountain range are visible from the city of Hamedan. Due to its high altitude, being located in the western plateau of Iran and distance from high seas the city of Hamedan has no major water resources such as sea, natural lake and coastline and the artificial lakes and lagoons of this city are the most important tourist attractions in this region. Increasing the level of geotourism and proper setting requires a coherent planning for Ekbatan Geopark, targeted advertising in the country, region and the world, and continuous cooperation between different sectors of the state and non-governmental organizations.

Soil improvement is a method used for increasing in quality of materials can be applied in pavement layers. From the standpoint of environmental geotechnics, application of the geotextile in many engineering projects can be effective method for soil improvements. Main aim of this study is laboratory evaluation of geotextile effects on bearing capacity of clay-gravel soil mixtures from Barandouz area for applying in pavement. In this research, gravelly soils was mixed with clay in 25, 50 and 75 percent. Geotextile effects evaluated in two conditions. First, in layers (in one, two and three layer). Second, as mixed pieces with 1×1 and 5×5 cm2 dimensions and weight percent of 1, 2 and 3. For determining bearing capacity of specimens, California Bearing Ratio (CBR) test performed in dry and saturate conditions. Also, in saturated state swelling potential of reinforced samples evaluated. Results of study showed appropriate geotextile layer number is one that is embedded in middle part of specimens or adding one percent by weight geotextile pieces with 1×1 cm2 dimensions randomly to reinforcing for improvement of bearing capacity. These values in saturated state significantly reduces swelling in specimens with clay content.

Soil erosion is one of the environmental, agriculture and natural resources problems. The aim of this research is applying the EPM and RUSLE models to the Jask - Gabrik Watershed, in order to estimate soil erosion and sediment. In this study, the factors affecting the water erodibility, consist of erosivity factor, soil erodibility, topography, vegetation cover, the sensitivity of soils and stones to erosion, land use type, steep slope percentage used in the models. Finally, the amount of erosion and sediment produced according to the RUSLE and EPM were compared with the observed sediment using Gabric sediment sampling gage station. The results showed that RUSLE model is estimated sediment, 30745 tons/ha/year while EPM model 10541.6 tons/ha/year. According to the results, the estimated erosion and sediment value of the RUSLE model is close to the sampling values (42414 tonnes/ha/year), then RUSLE model is more efficient. Finally, it is recommended, EPM model using for the initial phases, explanatory studies, overview, and identification while for more accurate and more detailed studies applied the RUSLE model.

Fluorite-barite-zinc-lead Solakan deposit is located in Sanandaj-Sirjan zone and in 125 Km of western Zanjan in the vicinity of zn-pb Anguran mine (about 500 meters). The dominant lithology of this region is consisting of amphibole schist, mica schist, graphite-bearing marble and gneiss with Precambrian age which is the oldest known unit in this region. Mineralization is occurred between the marbles (metamorphosed limestone and dolomite) in the lower part and mica schist in the upper part in the Solakan deposit. Graphite is distinguishable with an unspecified and scattered margin in all the metamorphic rocks of the region. SEM-EDX and XRD analysis confirmed occurrence of graphite in fluorite mineral in Solakan deposit. Graphite is present with regular shapes such as spherical, oral, hexagonal, cubic and in irregular shapes that generally fallow the cleavage and fractures in within fluorite. The structure of organic matter formed during the metamorphism of the Solakan-Angouran region was thoroughly investigated by FT-IR spectroscopy. Kerogen is present in all metamorphic stages with the loss of volatile matter with increasing of metamorphic degree and accumulation of carbon, graphite was formed. Based on this data, it was confirmed that the graphite inclusions in the fluorite probably display two sources with different temperatures in Solakan deposit.

The aim of this research is the estimation of uniaxial compressive strength and modulus of elasticity of Upper Red Formation sandstones using the physical properties in different cycles of freeze-thaw test. For this purpose, 6 large rock blocks from different locations of Upper Red Formation in southwestern of Qom were obtained. In this research, the freeze-thaw test was carried out in 30 cycles. Freeze–thaw test was carried out for 30 cycles and the variations of P-wave velocity, porosity, uniaxial compressive strength and modulus of elasticity of specimens were determined after every 10 cycles according to ISRM. The results of this study show that an increase in number of freeze–thaw cycles decreases uniaxial compressive strength, modulus of elasticity and P wave velocity, whereas the effective porosity increases. Based on this, it was observed that uniaxial compressive strength of specimens decreases between 41 and 85%, whereas the modulus of elasticity decreases between 47 and 70%. Finally, for prediction of strength properties of selected sandstones using the P-wave velocity and effective porosity in different cycles of freeze-thaw test, a series of predictive relationships were also proposed.

Nazloochay plain is located at north western of Urmia city in Iran. The approximate area of the plain is 508 Km2. It's located on the western coast of Urmia lake and is part of the Urmia basin. This research DRASTIC model was used to evaluate pollution vulnerability of aquifer of the region. DRASTIC model can be considered as the most common overlap index method used in these cases which considers seven hydrogeological parameters affecting ground water pollution including: Depth of ground water(D), net Recharge(R), Aquifer environment(A), Soil type(S), Topography(T), Impact of unsaturated zone(I) and Hydraulic conductivity(C). Combining these parameters of the model using GIS, indicated high pollution potential regions of aquifer and nitrate concentration has been applied to estimate the verification. DRASTIC vulnerability index of model was estimated between 38-153 for this case study, consisting of five ranges of pollution including: negligible; low (%44); little (33%); average (15%) and high (8%). According to designated vulnerability maps, the highest vulnerability potential is in central and southern section of the studying region. Based on nitrate concentration in pollution vulnerability shown in DRASTIC model, all area with high amount of nitrate were located in two categories of high and moderate ranges pollution susceptibility which confirms the model accuracy and preciseness.

Sistan and Baluchistan plain has been faced with significant reduction of groundwater level in recent years. One of the long-term drought conditions affected groundwater resources. One of the best measures for assessing drought and its effects is the use of the Standardized Precipitation Index (SPI). In this research, using this index, firstly, the long-term drought conditions in the eastern province of Sistan and Balouchestan were investigated and then the effects of drought on groundwater resources were investigated. In order to determine the drought periods, the data from 5 station stations from 1363 to 1393 and the qualitative data of 27 observation wells were used in two periods of 1389 and 1392, which have a good dispersion in the province. Tables of Cl, TDS, EC and Na values were prepared using statistical method to express qualitative changes. The results showed that, due to the decrease in rainfall, the average total of elements and materials in groundwater during the given period increased by 20 to 25 percent in water. Obviously, in addition to the natural factor that is drought, human factors such as population growth, land use change, plant growth, increased use of chemical fertilizers and pesticides have contributed greatly to this change in water quality. The continuation of this process of overburdening of rainfall and overtaking can bring the state of the plain closer to a critical state. Also, the central, western and northern regions will face more drought compared to the western and southern provinces of Sistan and Baluchestan.

The GolGir plain is located with an area of about 1600 hectare in 90km northeast of Ahvaz and 20km The southeast of Masjed Soleiman is located in the northwest of the Asmari anticline and the middle Karun Basin. The studied area is part of the Zagros china, located in the southwest of Iran. Formations exposed in this area are the oldest to the newest ones, respectively, including the present-day sediments, the sandstone-Marni Aghajari formation, limestone formations, Marni Mishan, Gachsaran, Gachsaran Formation, Asmari limestone formation. according to the demartenne classification, is a region with a semi-arid climat. Different formations due to the presence of certain rocks and minerals can have significant effects on the hydrological conditions of the area. In the study area, Asmari Formation has the highest potential for aquifer formation, and in terms of hydrogeology and hydrochemicals, it is the most favorable option for water harvesting among the formations of the region. Gachsaran Formation has a non-carbonated aquifer system, a virtual karstic with a medium to low recovery capability. Like the Aghajari Formation, the Lahbari member has an adverse effect on surface water and underground water quality. The presence of gypsum and marl layers in this section has a significant negative effect on the quality of runoff in terms of increasing the concentration of total soluble solids and sediment load. Bakhtiari conglomerate formations are generally seamless and split aquifers, which, despite the lack of discharge, are highly qualitative and continuously exploitable. In this paper, we will investigate the effect of petrology and lithological factors on the geostatic condition of the waters of this plain.

In this research, stress, strain and crustal shortening were calculated in Iran using Kastrov and Molnar methods and also role of gridding in the estimations has been investigated. In this view, numbers of 637 earthquakes with moment magnitude greater than 5.5 in time interval of 1909-2016 were applied. Pressure and tension directions, seismic strain resulted by two methods (gridding and every earthquake individually) and also horizontal and vertical crustal displacement velocity were estimated. Pressure and tension directions and seismic strain deduced by earthquake focal mechanisms, were calculated in three manners: every earthquake individually, 1°×1° and tectonical grindings. Data processing shows that pressure and tension directions and seismic strain are intensely related to the kind of the gridding. Also, there is clear difference between estimation of the strain with the two methods of Kastrov and Molnar. Nevertheless, it could be concluded that maximum deformation is going on in Dasht-e Bayaz and Qaen area in the eastern Iran. Vertical velocity estimations in High Zagros and Zagros Foredeep are crustal thickening and thinning, respectively, which is in accordance well to tectonic of the area. Although, this estimation in eastern and western Alborz are uplift and subsidence, respectively, which the later one is not in accordance with Alborz tectonic with an oblique collision.

The main objective of deposit estimation is prediction of physical properties of reserves based on sample analysis and modelling of dimension, shapes and grade distribution. Numerous factors such as shape, depth, dimensions and grade distribution effect on deposit modelling process. In this research, with evaluation on copper vein deposit, the effects of geometric factors constrains on modeling process evaluated. Also the suitable modelling technics for increasing the accuracy of modeling suggested. Whole of exploration information analyzed based on gathered data from 1457 m conventional core drilling boreholes, 4839 m Reverse Circulation boreholes and 2685 m production boreholes.
For increasing the accuracy, the modelling performed with creation of topograghic DTM, fault models, 3D model of boreholes, and mineralization. Based on assuming the 0.28 percent grade as cutoff grade, the reserve estimation with kriging and Inverse distance performed. The estimated reserve tonnage in kriging and Inverse distance are equal to 118250 and 125150 tone.

Salt rock is part of the group of inorganic chemical sedimentary rocks and is often made up of halite. One of the characteristics of soft materials is the shape variation related to the time or creep behavior. Creep is known as an irreversible deformation at the time and is often found in soft rocks such as rock salt, coal, and soft sedimentary rocks. Therefore, one of the basic requirements in the design of soft rock structural engineering is the correct modeling of the creep strain. One of the factors affecting the salt creep is the temperature. Knowing of the rate of rocks creep, especially the heat-treated rock salt, helps to promote the implementation of work in various oil and underground projects. In this study, the effect of temperature on the triaxial creep of salt rock has been studied. These tests have been performed under hydrostatic stress conditions, because these conditions usually prevail in the depths. Therefore, differential stress is zero in all states. Results show that with increasing temperature, the strain rate of salt rock increases nonlinearly and by increasing the confining pressure, the strain rate decreases.