نشریه زمین شناسی کاربردی پیشرفته
سال دهم شماره 37 (پاییز 1399)

Kosaj Fe ore occurrence is located in the Takab‒Takht-e-Soleyman‒Angouran metallogenic zone. At Kosaj, iron mineralization occurs as lens-shaped bodies and layers parallel to the foliation of muscovite schist and actinolite-hornblende schist units (equal to Kahar Formation). Ore minerals are magnetite along with minor pyrite, and quartz and actinolite present as gangue mineral. The ore minerals show disseminated, laminated, banded, massive, lenticular, vein-veinlet and replacement textures. Three stages of mineralization can be distinguished at Kosaj. The first stage is recognized as stratiform and stratabound lenses, laminated and disseminated crystals of magnetite-quartz and magnetite-actinolite bands parallet to the foliation of host rocks. Stage-2 mineralization is recognized by folding of ore bands, σ microfabric, boudinage and elongation of magnetite crystals, quartz pressure shadows and surrounding of foliation around magnetite crystals, and recrystallization of quartz and magnetite crystals. Stage-3 is recognized by brecciated magnetite-quartz vein-veinlets. Actinolitization, silicification and hematitization are main hydrothermal alteration types at Kosaj. Chondrite-nonmineralized REE pattern of host rocks and the mineralized samples indicate that mineralized samples are depleted in REE. Characteristics of Kosaj occurrence are comparable with metamorphosed and deformed volcano-sedimentary type of iron deposits.

Malayer-Aligoudarz-Isfahan metallogenic belt is located in the Sanandaj-Sirjan Zone, which hosts a large number of metal deposits. In this study, using Fuzzy-GAMMA method and analytic hierarchy process (AHP) based on weighting to exploratory layers were used Cu metal modeling in the studied area. First, all exploration layers and substrates, including lithology, geochemistry and fault density, they were weighted by Fuzzy-GAMMA method and were in the range of 0 to 1. Then fuzzy layers are then integration according to the weights assigned with 0.9 gamma (γ) value and Potential maps of Cu metal in the study area were obtained by Fuzzy-GAMMA method. Subsequently, using analytic hierarchical process Method (AHP), and forming appropriate matrix for the exploration layers, the layers were weighted and the potential map of Cu metal was obtained. Finally, the location of the Cu deposits and indices in the region was used to compare the accuracy of the applied methods. The results showed that (AHP) method compared with Fuzzy-GAMMA method determine more anomaly and the obtained anomalies by this method more consistent with existing Cu deposits in the region.

The existence of hot springs, extensive travertine deposits, hydrothermal alteration ranges, and the presence of faults in the Mahallat indicate an important geothermal system. In order to recognize the reservoir of the geothermal system as well as areas with magnetic anomalies, in the study area were conducate the magnetometry measurements In the length of 10 profiles,with total length 160 km and with an station spacing of 40 meters. The main purpose of this study is to estimate the bottom (Curie point depth) and top depth of magnetic sources also thermal gradient and heat flow using spectral analysis (centroid method). As well as conducted 3D inverse modeling of the magnetic data by Li-Oldenberg algorithm, in order to determine of geometries of the heat source. Conformity between of the obtained results by inverse modelling and centroid method indicate the existence of geothermal reservoir in the north part of study area. The results indicated that the range of variations in the bottom- depth, top depth of magnetic sources, varies from 1350 to 3400 meter,1230 to 2390meter, respectively.

Heterogeneity analysis and hydraulic flow unit (HFU) determination of the hydrocarbon reservoirs play an important role in the reservoir behavior. In the present research work hydraulic flow units of the Dalan and Kangan formations in selected two drilled wells (Well# B and Well# A) of one of oil fields in the Persian Gulf basin were determined. Heterogeneity value of the Kangan-Dalan reservoir is 0.84-0.86 in wells under study based on Lorenz coefficient calculation which is indicated high heterogeneity. The results revealed 3 flow units using improved stratigraphic Lorenz plot, core data, well logs and related equations. The method was used to divide formation in view of flow units in the environment of Geolog software. The results revealed that HFU1 - HFU3 and HFU2 are indicating higher and lower reservoir quality, respectively. Based on petrographic analysis of 1600 thin sections of Kangan and Dalan formations twelve sedimentary lithofacies were determined. These facies were also discussed in view of reservoir quality and diagenetic processes effects. Hydraulic flow unit distributions in 5 reservoir zones were exhibited that zone -4 is in the best quality state due to predominance of HFU1. Therefore, according to the present results the reservoir behavior is too much difficult to predict in other locations.

Subsurface spaces make restrictions for site selection and construction of structures. Although geophysics and drilling help engineers in this issue, but these are cost effective and time consuming. Therefore economic and fast methods should be considered for explorations. In this article an attempt was made to introduce a method for detecting and mapping subsurface spaces using thermal infrared images and other environmental effective factors. Assumption is land surface temperature somehow is being influenced by subsurface temperature. By the time the general conditions of land surface in carbonate rocks to be the same in terms of vegetation cover, antecedent soil moisture, illumination and altitude, any variations and anomalies of temperature on land surface may be attributed to inherent physical and hydrogeological conditions of carbonate rocks. Investigations showed that some parts of carbonate rocks in Shiramin region that are hosting subsurface spaces are relatively appeared cooler than the others on thermal images. Data integration based on applying base rules was taken place by means of ILWIS GIS and data analysis tools. As a result of such data integration, thermal anomalies related to inherent condition of carbonate rocks were identified and consequently spatial distribution map of areas hosting unseen subsurface spaces were prepared.

The Tutak area (northeastern part of Shiraz city) located in Sanandaj-Sirjan metamorphic Zone (SSZ) was chosen as study area because of having two important resources of iron and copper. Two metamorphic complexes of SSZ namely Surian and Tutak are the main host of these resources. The algorithms of Spectral Information Divergence and Adaptive Coherence Estimator were used to detect and distinguish rock units and indicator minerals. Using spectra of field samples, the pixel-based algorithm of Spectral Information Divergence enhanced greenschist and marble lithological units because of their significant spectral differences in VNIR region. Overall accuracy and kappa coefficients resulted by using this algorithm for detection of rock units were 0.83 and 0.72, respectively. Using data of USGS spectral library, the outputs of the sub-pixel algorithm of Adaptive Coherence Estimator successfully identified pixels with high abundances of chlorite and ankerite. Results showed that chlorite areas with its abundances more than 50% overlapped greenschist units, and the areas with chlorite abundances above 75% had acceptable conformity with the copper deposits, most prominent of which is Mazaijan copper deposit. The areas with more than 50% ankerite overlapped the marble units, and its abundances above 75% indicated an increase of the abundances of this mineral compared to the minerals of calcite and dolomite in this rock unit with approaching iron mineralization. So, based on study results, the Adaptive Coherence Estimator technique can be suggested to accurately detect and distinguish the minerals of the mineralogical reservoirs in study area.

The calcareous terrain of Ilam-Sarvak Formation at Leylia-Keynow Anticlines in the northeast of Khuzestan province has formed a very rich karst aquifer under the influence of geological structures. Many dolines at the heights of these anticlines, and also karstic springs such as Sousan spring with super-high discharge, springs of Tange-Sard and Dare-kool with a relatively high discharge indicate that the regional karst is well developed. Studies of geological structures show that the study area is affected by the basement faults of the Izeh and Balaroud shear zones. As a result, in addition to the development of fractures, the anticlines of the area have been merged with each other through structural interferences. The aquifer (anticline) of the Leylia-Keynow is the result of the same structural development, which, based on water budget estimation, can also be linked to the adjacent aquifers (or anticlines). The fault structure of another important in the study area is Mafaroun thrust fault which has played a substantial role on occurrence of above springs by placing the Ilam-Sarvak Formation in front of the Pabdeh-Gurpi impenetrable Formation, as well as creating high fracturing. Field surveys also show that faults and fractures are more frequent in the study area. These types of fractures and faults play a key role in controlling the pattern of general flow and water transfer. In sum, these results indicate that the karstic aquifer in the study area is controlled by a specific hydrotectonic regime.

Momen Abad Mining area is a part of the Eastern Iranian Bentonite Zone. Mineralogical studies revealed the presence of cristobalite and smectite as the main phases and plagioclase, feldspar and amorphous silica occur as the minor phases and this mineralogy favors the application of this mineral assemblage in pelletizing industry of iron concentrate. Scanning Electron Microscopy of bentonite clumps indicates that smectite clays show wavy sheet like morphology with overgrowth of cristobalite and bentonite sheet grains occur as aggregates with flocculated appearance and spherical and angular grains with popcorn texture. Based on the Na and Ca contents it was found out that the bentonites are compositionally Na members. Water absorption tests on 104 samples indicate that the Momen Abad samples from trenches shallower than 15m are not favorable for pelletizing however deeper samples show acceptable parameters for this purpose. In addition, the results obtained from comparison of eight mines indicate that Momen Abad and Deheshk mines with absorption of higher than 600 are more convenient than samples from Sanajan, Tighab, Khosh’hal, Ebrahimi, Mortezanejad, and Shirazi mines.

Investigations on Tectonic setting of Mud Volcanoes show that these located mainly in active convergent margins with high rate of seismicity along fault zones, fault related folds and anticlinal axes. In this research, firstly, investigated on their relationship with geological structures (such a faults and folds) and regional seismicity and then, focused on determination of tectonic setting of mud volcanoes in Western part of Golestan province. This research shown that approximately 45 mud volcanoes spread in study area that five mud volcanoes: Gharnyaregh, Naftalijah, Suficam, Incheh and Gomishan are active. These mud volcanoes have tectonic related indicators such as: alignment along the main faults and seismic trends and also, located on anticlinal axes with hydrocarbour reservoir. In regard to these facts, we can deduced that these mud volcanoes are related to tectonic in a Transcurrent plate boundary which located in western Kopet dagh (with Continental crust) and south Caspian Basin (with oceanic crust) boundaries in a zone with North-South trend and 30 Km width.

The Kazhdumi Formation is a Middle Cretaceous whose base in the Abadan plain is composed of sandstone, shale and limestone, and is equivalent to the Burgan Formation in Arab countries. In this study, we investigated the reservoir quality of one of the major oilfields of the Abadan plain using thin sections, core data such as hydrocarbon impregnation, porosity, permeability, and well logs. According to petrographic studies, 4 sedimentary microfacies and 5 lithofacies have been identified in the Burgan Formation deposited in the carbonate ramp to the Delta. Diagenesis processes include dissolution, fracture, cementation, dolomitization, condensation, glaconite, hematite and pyrite occurring in three marine, meteoric and burial environments. Among the diagenesis processes, dissolution and fracture have had a special role in enhancing reservoir quality, and cementation, dolomitization and compaction have been the most important determinants of reservoir quality studied. Core studies and wellbore diagrams show that the sandstone and carbonate facies have the highest and the lowest amount of porosity, permeability and hydrocarbon impregnation, respectively, and the Chilean facies is in terms of reservoir quality between these two facies. Quartz Arenite rock facies was identified as the main reservoir zone in the studied oil field.

Gardeneh-Shir zinc and lead deposit is located at 38 km southwest of Ardestan in Central Iran. The host rocks of this deposit includes carbonates of Middle Triassic Shotory Formation juxtaposed over Upper Triassic Naiband Formation by thrust faulting. The mineralization in these deposits is in the form of vein-veinlet, breccia and filling of karstic cavities with dolomitization and silicification and mainly controlled by Strike-slip faults with the normal component and normal faults with strike slip component those are cross cutting older generation of thrust faults. The results of fluid inclusion studies of on quartz and dolomite in Gardeneh-Shir deposits Area show a fluid with a salinity of 23.2-18.6% by weight of salt, temperature range of homogeneity between 91 -162 ° C and a density of 1.09-1.056 g/cm3. The combination of fluid inclusion and EPMA analysis of Zn / Cd (879%) elemental ratios in sphalerite mineral has confirmed low temperature generation of Gardeneh Shir deposit. According to the results of our studies including host rock type, mineralogy, mineralization control structures, salinity and temperature it can be considered that the mineralization of zinc and lead are the mining region of Gardeneh-Shir deposits in the category of MVT type deposits

Landslide is a destructively geohazard in hilly regions that is responsible for remarkable devastations. Due to geological and geomorphological features as well as land-uses, Masjed Soleyman area is prone to landslide disaster so that 70 landslides record in the region. For this reason, producing the landslide susceptibility map and studying landslides triggering factors are essential for mitigating damages. For this purpose, nine landslide causal factors were considered, including altitude, slope, aspect, stratigraphy, faults and lineaments, rain, land use, proximity to roads and drainages. Then, landslide susceptibility maps were developed by coupling the analytic hierarchy process (AHP) and the frequency ratio (FR) methods in a GIS environment. The resulting maps were categorized into five classes, namely, very high, high, moderate, low, and very low. Results demonstrate that about 69.45% (AHP) and 56.94% (FR) of the study area belongs to the very high and high classes, respectively. Furthermore, prepared maps were validated using 21% of all mapped landslides considered for testing the model. The percentage of validating landslides locations in moderate, high and very high classes in each map was computed (AHP=66.67% and FR=73.33%). Although both models produced reasonable accuracy, the FR model is more accurate than the ones. Therefore, the FR map is trustworthy for planning future developmental activities and environmental protection throughout the study area.