نشریه زمین شناسی کاربردی پیشرفته
سال دهم شماره 38 (زمستان 1399)

Mineralization in the Halab occurrence occurs as Au-bearing silicified-sulfidic zone within Precambrian mafic schist sequence. Ore minerals include arsenopyrite, sphalerite, pyrite, chalcopyrite, pyrrhotite and gold, and quartz, actinolite, clinopyroxene, and chlorite are present as gangue minerals at Halab. The ore minerals show banded, laminated, disseminated, veinlet, brecciated, vug infill, colloform, replacement, and relict textures. Alteration are consist of actinolitization, silicification, and chloritization. Four stages of mineralization can be distinguished at Halab. Gold mineralization is related to hydrothermal stage (stage 3) accompanied with arsenopyrite. Field and analytical results reveal that primary mineralization at Halab occurs as sub-economic stratiform and startabound, laminated and disseminated Zn‒Cu mineralization coeval with the deposition of the volcano-sedimentary units which that overprinted during later metamorphic-deformation process. This primary Zn‒Cu mineralization is comparable with metamorphosed and deformed laminated and disseminated parts of the Besshi type massive sulfide deposits. Gold mineralization is related to late hydrothermal phase which is thought to be result of Miocene magmatism in the Takab–Takht-e-Soleyman–Angouran zone. Investigation of alteration zones within Precambrian metamorphosed units which have spatial relationship with Miocene magmatism, is, therefore, of major importance in exploration of this type of gold mineralization at the Takab–Takht-e-Soleyman–Angouran zone.

The study of Tectonic activity, and in particular those earas with relatively high activity in the Holocene and late Pleistocene is important to evaluate the earthquake hazard. The purpose of this study is to investigate the role of tectonic factors in the development and morphological changes of the alluvial fans of Agh Chay. In this study, the topographic maps, geology, satellite photos and the digital elevation model (DEM) were used as the main research data. In addition, the morphology of the alluvial fans of the region was studied closely and through the field study. Then, using the geomorphic indices which includes the sinuosity of the mountain in-front (SMF) Ratio of valley floor width to valley height (VF), Drainage Asymmetry factor (AF), Stream Length-Gradient Index (SL), Transverse Topographic Symmetry Factor (T), Fan Comicality Index (FCI), the region in terms of tectonic activities were assessed. Through combination of these indexes, the index of active tectonics (Iat) can be obtained. The results of study showed that Agh Chay, Zarabad Chay, Dibak Chay and Zavieh Chay have very high activity. Altogether, according to the calculated morphometry indexes, it can be concluded that the region has medium to high tectonic activity, but there are changes in tectonic activity in the region, which can be attributed to increase tectonic activity from north west to south east of the region.

The presence of active and Quaternary (young) faults in the eastern part of Iran has made this area a seismically active area. There are many ways to identify and evaluate seismic hazard for a range. In this study, two methods of seismic analysis have been used for statistical analysis and tectonic morphological indices and neo-tectonic evidence of Chahak fault activity and seismicity located 30 km from Arianshahr (South Khorasan). Compare these two methods. Finally, by studying and calculating the tectonic indices S, BS, AF, T and Smf that their numerical averages are 1, 1.88, 59, 0.40, 1 and combining them and obtaining the Active tectonic index (Iat) equal to 1.94 as well as seismic survey of Chahak Fault revealed that Chahak Fault has relatively high activity in the study area and it can be said that seismic analysis by statistical method and tectonic morphological analysis is a suitable tool. To estimate the amount of tectonic movements and earthquake hazards are in range to identify and analyze seismic hazard areas as well as seismic springs. To reduce the casualties and financial losses during the earthquake, we can make the most of the benefits of the earthquake and change our view of the earthquake.

Assessment of data uncertainty increases our ability to study and accurate understanding of about real world, because awareness from uncertainty of resources and remove error for improving the obtained results is one of the most important items in the remote sensing science. Since the digital elevation model (DEM) extracted from different sensors and geometry, Therefore selection of the most suitable DEM that provide better ground conditions is the one of the main needs for experts in this field. The aim of this study to vertical accuracy assessment of the ASTER and SRTM digital elevation model compared to the elevation data from topographic maps that prepared by the Iran National Cartographic Center in the 12 city from Khuzestan province. In order to evaluation the accuracy of the data, the Mean Error (ME) index and Root Mean Square Error (RMSE) index are used. The result of evaluation ME index for the cities with topographic map for ASTER and SRTM data showed the value 6.08 and 2.34 meter, respectively. Also, the result of RMSE index for ASTER and SRTM data showed the value 6.94 and 3.46 meter, respectively. Therefore more, the result showed that in most cities of Khuzestan province the DEM derived from SRTM has a higher accuracy than the ASTER digital model; Since the SRTM data have a low uncertainty, Therefore in studies related to the extraction drainage network, drainage density, physiography of the watershed area, runoff or geology, it is suggested that SRTM elevation model be used.

From 2011 to 2013, several major earthquakes occurred in the Makran Seismotectonic zone (Iran and Pakistan). The low event interval of these earthquakes in a tectonic zone may indicate their interaction. In this paper, the interactions between 2011 Dalbandin earthquake of Pakistan, 2013 Saravan and Goharan earthquakes of Makran seismotectonic zone in SE Iran was investigated by calculating the Coulomb stress changes. Maps and cross sections of coseismic stress changes show that Saravan and Goharan earthquakes have occurred in the stress enhanced areas indicating the positive effect of Dalbandin earthquake on trigerring the mentioned events. In order to quantify the seismicity level changes, statistical parameters including b-value, seismicity rate and temporal changes of local standard deviation of gradient (lsd) were calculated over a 10 year period (5 years before and after the Dalbandin earthquake).The results show that the seismicity rate of Makran seismotectonic zone has significantly increased after this event. The temporal variation graph of lsd parameter also decreases at the time of the Dalbandin earthquake event, indicating an increase in seismicity rate in the region. In overall, the results indicate that the Dalbandin earthquake is the beginning of an active seismic period in the Makran subduction zone on which the peak of activity occurred in 2013 with two years delay.

Abstract Conventional methods for determining the geotechnical properties of the soil are usually costly, destructive and time-consuming. Electrical resistivity is one of the subsurface characteristics of soils that can easily be measured without any invasive action. It is very useful to develop an acceptable correlation between electrical resistivity and shear strength parameters in construction sites. In this study, a correlation was developed between the electrical resistivity and each of the parameters of cohesion and internal angle of friction, with laboratory measurements. Based on the regression analysis, there is a relatively strong correlation with the coefficient of 0.7769 between the electrical resistivity and the cohesion parameter. Regression analysis also shows a relatively good correlation between the electrical resistivity and the internal angle of friction parameter. The results showed that the electrical resistivity relationship with each of parameters of cohesion and internal angle of friction is linear .

The study area is located 60 km southeast of Abadeh city in the northeastem part of Mountain Hambast .In the concerned area there exists complete outcrops from the Middle to the Upper Permian , and has two stratigraphic sections in the Hambast valley as was based on field evidence , petrography and geochemical analysis based on elemental analysis of (EDS) and (EPMA) methods. Two main groups of dolomite minerals including primary dolomite and secondary dolomite were identified .The Primary dolomitic group (called dolomicrites) show mosaic texture and are more anhedral , The second group (dolomicrosparites ) are subhedral. The dolosparites are often subhedral and uhedral.In dolomicrites , Mg is lower than other dolomites due to the highe Ca content.In general , the amount of Sr in the dolomites studied decreases from dolomicrites to dolosparite and increased Sr in dolomicrites is due to the function of diagenesis processes on aragonite shrlls.

Jareh dam is located in the north east of Ramhormoz city, in Khuzestan province. In order to identify the main factors governing the hydrochemical changes and to recognize geochemical processes controlling the water resources of Jareh dam, hydrochemical analysis of twenty water samples was carried out. In this research, multivariate statistical techniques Hierarchical cluster analysis (HCA) in two ways, R-mod and Q-mod and principal component analysis (PCA), discrimination analysis (DA) along with hydrochemical methods have been used. Based on HCA founding, three different groups of water samples were observed according to PCA. The PCA illustrated that the first factor depicted 63.73%, and the second factor indicated 18.13% of the hydrochemical changes. The DA results confirmed the created groups by CA, Cl- and SO4-2 could be considered as determinative variables for differences between present groups. The Piper diagram was used to identify the water type and the group of samples, where most of them represent a sulfate-calcium type. The study of saturation indexes, ion ratios, Gibbs charts and the results of multivariate statistical techniques illustrates that breakup and erosion of sediments generated by the Gachsaran formation is the main factor for the deterioration of the Jareh dam water in the south-east zone.

The Garmab area is located in NW of Kamyaran and belongs to the Kermanshah Ophiolite Zone. This complex is located between the Sanandaj-Sirjan and the Zagros thrust zones. Peridotite rocks in the complex were replaced by serpentinite completely or partly due to hydrothermal alteration. Petrographic studies show that the serpentines formed by hydration of both olivine and orthopyroxene minerals. Electron microprobe and X-ray diffraction (XRD) analyses of the samples indicate that the Garmab serpentinites contain all the three serpentine polymorphs (chrysotile, lizardite, antigorite). Those serpentines replacing olivines have higher SiO2 and lower Al2O3, Cr2O3 and TiO2 than those replacing orthopyroxene. This clearly demonstrates their different sources. The calculated phase diagram for the studied samples shows that serpentinites probably formed in two metamorphism events; the first one includes alteration and hydration of harzburgite in T< 200 oC and P < 4 kbar, while the second one occurred due to increasing T and P to more than 400 oC and 4 kbar.

South Ghabaqloujeh gold deposit is located 7 km southwest of Saqqez in the northwestern part of the Sanandaj–Sirjan zone. The rocks in the deposit area predominantly consist of Precambrian and Cretaceous volcanosedimentary sequences of schist, phyllite and marble which intruded by granitoid bodies. The main gold reservoir in the deposit is hosted inside a lens-shaped granitic body that is intruded along a Northeast - Southwest shear zone. The high-grade gold ores belong to highly deformed mylonitic and ultramylonitic granitoid rocks which associated with quartz, sericite-muscovite, carbonite and sulfide alteration minerals. Ore mineral assemblages of the deposit are simple and consist of pyrite, chalcopyrite, galena, sphalerite, magnetite, electrum, bismothinite and sylvanite. Electrum grains with less of than 50 microns in size has been found as intergrowth with quartz, carbonite and biotite and also in the form of inclusion and veinlet in pyrites. Fluid inclusion studies indicate homogenization temperatures between 162 and 255°C and salinity between 0.6 to 17.1 wt% NaCl eq. The study indicates that main characteristics of the geology and mineralization of the South Ghabaqloujeh gold deposit is similar to orogenic gold deposits

Roads constructed on problematic soils may have adversely influenced by the behavior of their geotechnical properties. These soils are undergoing a high degree of compressibility, low permeability, low compressive strength (lower than 40kpa), and high potential to swell with high water content as it comprises minerals, including montmorillonite which can absorb water that causes heaving, cracking and the breakup of the road pavement. Improvement of these soils is essential to improve the strength of the soil and thus partly decrease the thickness so f road layers (Amhadi et al., 2018). Where road constructions through floodplains encounter troublesome materials, one of the available classical options had always been to excavate and import suitable materials for replacement as they were either weak subgrades soil layers with weak geotechnical materials. Current limits cause assists geotechnical engineers to improve the in site soils by applying the usage of stabilizer materials. The main objectives of this research were to investigate the effect of GGBS, with and without lime, on the engineering behavior unconfined compressive strength (UCS) of the test soil and to identify the reaction products of the stabilized materials to determine the mechanisms by which changes in engineering properties are obtained by using SEM images.

In the last decade, the phenomenon of subsidence has occurred in a large part of the plains of Iran due to excessive harvesting of groundwater and climatic drought. This has caused a great deal of environmental, economic and social damage. In this study, the effect of fine-grained layer thickness and groundwater level drop on the Tehran-Karaj-Shahriar aquifer is investigated. In the first step, fine-layer thickness maps, groundwater level changes, bedrock level, permeability and hydrodynamic coefficients (storage coefficient and transferability) were prepared in GIS. Subsequently, the extent and location of the subsidence map was prepared using differential interferometry and ENVISAT ASAR satellite imagery from 2004 to 2009. The results of this study show a maximum subsidence rate of about 17 cm in the central part of the aquifer and an average groundwater level reduction of 0.42 m / year. Comparison of the subsidence map with the groundwater change map shows that the amount of subsidence in the northwestern aquifer with the greatest decrease in water level (27 m) is low (less than 0.5 cm / year) in contrast to the maximum subsidence (17 Cm/ year) occurred in central areas showing a 5 to 10 m drop in groundwater level. To interpret these results, fine-grained layer thickness maps, permeability, hydrodynamic coefficients and bed scales were used. The results confirm that the areas with maximum subsidence are in accordance with the thickness map of the fine-grained layers.