The highly deformed Zhob ophiolite comprises the Ali Khanzai, Naweoba, and Omzha blocks. Each of these blocks contains both felsic and mafic dyke swarms. The felsic dykes occur as patches and pods in gabbroic bodies of crustal sections while mafic dykes crosscut the mantle peridotite of these blocks. Felsic dykes are plagiogranite and are composed of quartz, plagioclase and accessory ferromagnesian minerals whereas mafic dykes are basaltic in composition and contain largely plagioclase, clinopyroxene, and hornblende with minor quartz grains. Major, trace and rare earth elements have been analyzed in the felsic and mafic to assess the tectonomagmatic setting of the Zhob ophiolite. The felsic dykes are calc-alkaline oceanic plagiogranites while mafic dykes are tholeiitic in composition. Chondrite normalized patterns for the felsic dykes are characterized by low values of the REEs and positive Eu anomalies which indicate that they were formed by partial melting of basic rocks under hydrous conditions. The mafic dykes show very slight Nb depletion and enrichment in large ion lithophile elements (LILE) over high field strength elements (HFSE) which suggest that mafic dyke swarms are derived from an undepleted mantle source. Oceanic rocks with such characteristics are generally thought to have formed by processes involving a subduction zone component in the source region by fluids released from the subducting slab. These features suggest a subduction related setting which indicates an island arc, back arc or supra-subduction zone affinity for the formation of both felsic and mafic dykes of the Zhob ophiolite.
The Qobadlu intrusive body in the northern part of the Sanandaj-Sirjan Zone (SaSZ) has been recognized as a remnant of Cretaceous magmatic activity in the NW Iran. The Qobadlu gabbroic body has a calc-alkaline affinity. Based on the zircon dating (U-Pb), the coarse grained Qobadlu gabbro were crystallized at 99 Ma. The Low SiO2 and high Mg # Cr and Ni contents of the Qobadlu rocks can be indicate the upper mantle source for parental magma. Positive anomalies of the LILE and LREE, coupled with negative anomalies of Nb and Ti, and high ratios of La/Nb (1.3-3.3) and Ba/Nb (20-90) can be indicate that the samples are sourced from an amphibole enriched spinel lherzolitic mantle and developed through Neo-Tethyan subduction regime. Variations in incompatible elements suggest the crustal assimilation and fractionation crystallization during magma ascent. Considering the Cretaceous magmatic activity of the calcalkaline, these rocks have seemingly formed in the extensional basin related to the Neotethys subduction.
Accurately estimating the construction duration of long tunnels during the feasibility and initiation phases is crucial. Traditional estimation methods often lack precision. This paper introduces novel simulation-based approaches to provide more accurate forecasts of tunnel construction time, thereby minimizing the gap between planned and actual durations. This innovation involves identifying risks influencing tunnel construction, categorized as known and unknown, by experts. These risks are then ranked and weighted using the Fuzzy Analytic Hierarchy Process (FAHP). Significant risks are simulated as inputs in MATLAB software using the Monte Carlo method. The results indicate a six-year construction duration for the identified risks. The probability of adhering to the schedule is 100% in the first year, decreasing to 89% in the second year, 92% in the third year, and 90% in the fourth, fifth, and sixth years. For unknown risks, the probability is 90% in the first year, 93% in the second year, 90% in the fourth year, and 92% in the fifth and sixth years. Based on these findings, contingency and management reserves should be added to the forecasted schedule in accordance with the PMBOK standard to minimize discrepancies between planned and actual schedules.
This paper discusses shortening and strain in folds, highlighting the structural variation in the southern Kerman coal field. In this tectonically active region, the stress resulting from compression and tension in central Iran has largely manifested as folding and faulting, which constitute the major deformation of the area. The research results show compression of the folds in the study area. The results also indicate the complete reversal of the relative ages of ductile and brittle structures, due to faulting that sheared the limbs of most folds in the region. As can be inferred, except for the Kuhbanan and Lekarkoh faults, which existed before the folds and hence played a major role in the area's formation, the remaining faults in the region formed after the folds. In this aspect, the maximum shortening percentage in the area is 70% for the Babnizo fold, and the minimum is 42% for the Eshkli syncline.
The Mekong Delta is the third-largest delta in the world, with a large population, a significant food production area in Vietnam and home to large-scale biodiversity, is seriously affected by erosion-accretion of the coast, land subsidence. Several dams have been built upstream of the delta (Manwan, Nuozhadu...), and large-scale commercial sand mining in the river and delta channels, along with subsidence caused by groundwater extraction, are the causes of sediment decline in the Mekong Delta. This affects the daily lives of more than 21 million people. Using high-resolution satellite imagery (Landsat) for the period 1989-2020, this paper assesses erosion-accretion rates at the Mekong estuary to Ca Mau cape. Extracting the shoreline using the Normalized Difference Vegetation Index used to measure vegetation change and the Digital Shoreline Analysis System used to analyze changes in the shoreline. The results show that the Mekong estuary is having an alternating process of erosion-accretion, the balance of erosion-accretion tends to imbalance with dominant accretion. The Mekong estuary area, including the Tieu, Dai, Ba Lai, Ham Luong, Co Chien, Cung Hau, Dinh An and Tran De mouths, experiences erosion and accretion ranging from 1.37 to 120.98 m/yr and 74.94 to 117.06 m/yr, respectively. From My Thanh mouth to Ca Mau Cape, with erosion ranging from 66.07 to 115.5 m/yr and accretion from 29.67 to 91.06 m/yr, respectively. Our research emphasizes the fragility of the Mekong Delta coastline and underscores the critical role of remote sensing imagery in effective shoreline management.
This study presents a comprehensive petrophysical evaluation of two wells in LADE field located in the Niger Delta Basin. The study utilized an integrated approach for interpretation which involved the usage of GEOLOGTM and PYTHON 3.12.4 softwares. Geolog was utilized for advanced petrophysical analysis, integrating core data to enhance reservoir characterization and interpretation. Well-log data, including gamma-ray, resistivity, porosity, and permeability logs, were processed and analyzed using Python for data manipulation, statistical calculations, and visualization. The results of the study provide crucial information for reservoir characterization, reservoir modeling and decision-making processes in hydrocarbon exploration and production activities in the Niger Delta region. Reservoir sand bodies A1 and B1 within LADE-001 well have gross thicknesses of 138.9-130.6 ft., net-pay thicknesses of 62.5-21.5 ft. and net-to-gross (N/G) ratio of 0.0215-0.165. Effective porosity stands at 24-25%, water saturation at 28-29%, hydrocarbon saturation at 72-71%, while the volume of shale stands at 7 8%. These parameters collectively classify reservoirs A1 and B1 as robust hydrocarbon-bearing reservoir, showcasing good thickness, moderate net-to-gross, low shale volume and favorable porosity. Sand bodies in LADE-002 well revealed gross thicknesses ranging from 139-1467 ft., net-pay thicknesses of 27.5-148 ft., N/G ratio of 0.019-0.26. The values of effective porosity range from 22-27%, with the other parameters and their ranges expressed as; water saturation: 20-34%, hydrocarbon saturation: 66-80% and volume of shale: 6-8%. Reservoirs B2, C2 and D2 are classified as robust hydrocarbon-bearing reservoir, featuring good thickness, moderate/low net-to-gross, low shale volume and favorable porosity while reservoir A2 revealed fair to good attributes due to poor net thickness, low net-to-gross, low shale volume and favorable porosity. The delineated reservoirs are characterized by favorable porosity and permeability with a high tendency to accumulate hydrocarbons and flow during production.
Poorly predicted abnormal pressure has contributed to drilling non-productive downtime in most exploration fields in Niger Delta Basin. However, several advances have been made to improve pressured-related non-productive downtime during drilling. Despite the advances, it has become more critical during pre-drill geopressure prediction. This study has estimated Eaton's and Bower's prediction models ahead of the drilling bit in a recent drill campaign. The aim is to reduce non-productive downtime for a proposed 1000ft untested hydrocarbon reservoir (Kulon XII deep well) in the Onshore/Shelf, Niger Delta Basin. The study projected the accuracy level of Eaton's or Bower's prediction model ahead of drilling the Kulon XII deep well. Offset well result closest to the proposed High Pressure, High Temperature (HPHT) Kulon XII deep exploration well confirmed that pore pressure prediction at shallow depths (less than 11,750ft) confirmed that Eaton's model predicted pore pressure below hydrostatic gradient, while Bowers model at same condition overestimated it. At depths greater than 12,000ft, the Eaton and Bowers prediction model matched with the measured pore pressure. Both models were used to predict pore pressure at deeper intervals of the proposed well. The predicted pore pressure profile from the offset well revealed the onset of mild overpressure at depths greater than 11,900ft. Therefore, the seismic velocity was scaled by a factor of +/- 5% to determine the mud weight that will be required for drilling of the Kulon XII deep well in order not to experience kick at depths greater than 13,000ft.
Biostratigraphy and paleoecology of the Azkand and Anah formations were investigated in Wadi Al-Khazgha Algarbi, Anah area, Anbar Governorate, Western Iraq. Twenty-two samples were taken from one section close to the asymmetrical ENE Anah Anticline (Wadi Al-Khazgha Algarbi), containing twenty species of larger benthic foraminifera and skeletal fragments of brachiopods, corals, pelecypods, gastropods, and calcareous algae. The carbonate deposits of the Azkand Formation from the Chattian age consisted of white, fossiliferous larger benthic foraminifera (Lepidocyclina), well-bedded, chalky limestone in the lower part, and recrystallized limestone. Anah Formation was mostly composed of creamy, porous, massive-bedded, hard recrystallized, fossiliferous (coralline red algae and larger benthic foraminifera) limestone. Based on the identification of the larger benthic foraminifera and other skeletal grains, two biozones (Lepidocyclina Partial-Range Biozone and Miogypsinoides complanatus-Rotalia viennoti Assemblage Biozone) of Azkand Formation and two assemblage biozones (Austrotrillina asmariensis-Archaias kirkukensis Assemblage Biozone and Peneroplis evolutus-Austrotrillin asmariensis-Dendritina rangi Assemblage Biozone) for Anah Formation of Late Oligocene-Early Miocene (Chattian-Lower part of Aqutanian) age have been recognized. The biotic relationships found in this study imply that the Azkand Formation carbonate sedimentation occurred in a marine environment, tropical to subtropical, under oligotrophic to mesotrophic conditions at depths water of 12-80m, and Anah Formation was thriving in normal to slightly saline, tropical to subtropical waters, at depth of 40-80 m.
This research used the Ground Penetrating Radar (GPR) technology to elucidate the geological and structural attributes of gypsum deposits in the Bala area of Ankara. Ground Penetrating Radar (GPR) is a prevalent method for high-resolution imaging of subsurface formations, identifying discrepancies in electrical characteristics attributable to lithology and groundwater concentration. Ground Penetrating Radar (GPR) measurements were conducted along 19 profiles inside the research region, and the underlying structures in these profiles were meticulously studied. The collected data were analysed to delineate the thickness and distribution of gypsum deposits and their effects on groundwater. Regions with elevated resistivity indicates gypsum formations, while regions of reduced resistivity correspond to clay strata and water-saturated sediments. Specifically, karst cavities were absent in the majority of the profiles, suggesting that the gypsum deposits in the region exhibit resistance to karstification. Furthermore, it was determined that the gypsum resources are commercially viable and appropriate for extraction. This study pointed out that Ground Penetrating Radar (GPR) is a proficient method for delineating gypsum deposits in intricate evaporitic settings, with maximal deposit thicknesses of up to 10 meters in certain profiles and an absence of substantial karstic cavities, hence enhancing operating safety.
Assessing the impacts of drilling and production activities on induced stresses in oil and gas wells is crucial for addressing various geomechanical challenges such as wellbore instability, sand production, and potential blowout incidents. Mechanical instability arises when induced stresses surpass the strength of the formation. Since reservoir rock behaves as a porous medium, accurately calculating effective stress around the wellbore, based on Biot's theory, is essential for estimating induced stresses. Understanding Biot's coefficient is pivotal, particularly in high-pressure and soft rock reservoirs, as it influences the effective stress derived from total stress and pore pressure. However, laboratory measurements for Biot's coefficient are expensive and timeconsuming. Therefore, this paper developed the analytical solution for induced stresses in the anisotropic stress field in both Darcy and non-Darcy flow regime and investigated the impact of variations in Biot's coefficient on induced stresses around wellbores, focusing on radial, tangential, and vertical stresses. The study highlights the significance of Biot's coefficient in modulating effective stresses in oil and gas wells. Additionally, it addresses the prevalence of non-Darcy flow alongside Darcy flow in scenarios involving gas reservoirs, HPHT wells, and hydraulic fractures. Thus, the effect of Biot's coefficient on induced stresses is explored in both Darcy and non-Darcy flow regimes. Results indicate that increasing Biot's coefficient in the Darcy flow regime reduces radial, tangential, and vertical stresses around the wellbore, suggesting lower stress levels in the soft rock relative to hard rock. Conversely, in the non-Darcy flow regime, increasing Biot's coefficient reduces radial stress while initially increasing tangential stress near the wellbore wall, followed by a decrease at farther distances. The opposite trend is observed for vertical stress, highlighting the dependence of stress patterns on the flow regime. Solving stress equations for a typical reservoir under both Darcy and non-Darcy flow regimes, it is concluded that the variation in Biot's coefficient has a negligible effect on induced stresses under low drawdown pressure reservoirs. This research provides valuable insights into the complex interplay between Biot's coefficient, flow regimes, and induced stresses in oil and gas wells, aiding in developing effective strategies for mitigating geomechanical risks.
The Gazu is the only Cretaceous-Paleocene Cu porphyry deposit in Iran and is located in the Tabas block with outcrops of scattered basement fragments attributed to the Neoproterozoic northern Gondwanan active margin continental arcs. The main question is why only a small, uneconomic porphyry deposit formed in this region? In this paper, we discuss this issue by calculating the oxygen fugacity of ore-bearing and barren intrusive rocks and zircon trace element geochemistry. The ore-bearing intrusions have both Cretaceous magmatic and Neoproterozoic inherited zircons. The Cretaceous-early Paleocene magmatic zircons have very low to moderate (10-385, mean 110) Ce4+/Ce3+ ratios. These ratios are lower (26-143, 68 on average) for inherited zircons. The oxygen fugacity (estimated log fO2) of Cretaceous Gazu porphyry magmas ranges from O FMQ-1.4 (+/- 1.3) to O FMQ +2.3 (+/- 1.3) (OFMQ similar to +1 on average). The log fO2 from Neoproterozoic inherited zircons are in the range of OFMQ-1.2 (+/- 1.3) to OFMQ + 1.6 (+/- 1.3). A more positive range of Ce4+/Ce3+ and OFMQ values for Cretaceous zircons compared to those of inherited Neoproterozoic zircons indicates a more oxidized source magma during the crystallization of Cretaceous magmatic zircons. As the magma ascended through the reduced continental crust, AFC and mixing processes in the MASH zone reduced the log fO2 of the parental magma. Low-volume melting of the subcontinental crust, influenced by low-volume slab-metasomatized mantle magmas, led to the formation of a single, small porphyry copper deposit (Gazu).
Data inversion is one of the most important and challenging steps in geophysical data analysis. One of the vital issues in doing so is underdeterminacy, that is, the available data being less than the parameters of the model. Tikhonov Regularization, which is done by adding a stabilizing functional to the misfit and making a target function, is one of the most common methods for solving this problem. The important challenge in Tikhonov Regularization is determining the regularization parameter automatically in each iteration. Unbiased Predictive Risk Estimator (UPRE) is one of the usual methods proposed for tackling the mentioned challenge. Due to its high convergence rate and acceptable results in synthetic and real data, especially in geomagnetic and gravity explorations, it has received much attention. Therefore, here, the method above was used for the inversion of the 2D magnetotelluric data, and its results were compared with the methods of Activated Constraint Balancing (ACB) and Discrepancy Principle. To do so, the standard program "MT2DinvMatlab" was used as a basis, which uses the methods Lavenberg-Marquardt and ACB for inversion and automatic estimation of the regularization parameter, respectively. Next, this program was modified to estimate the regularization parameter with both ACB, UPRE, and Discrepancy Principle. In order to compare the results of these methods, a relatively complicated synthetic case and a real case of geothermal exploration in the Sabalan region were employed. Finally, the efficiency of UPRE was established in terms of yielding accurate models, low computation time, and high convergence rate.
This paper discussed the depositional environment and provenance analysis of the siliciclastic rocks of the Kerman Formation for the first time. To determine the Kerman Formation's depositional environment and provenance sedimentological, petrographic, and geochemical investigations have been conducted accordingly. The Kerman Formation (similar to 1017 m-thick), lithologically consisting of massive polymictic conglomerates interbedded with some minor sandstone layers, is well-exposed in NE Central Iran. Through detailed sedimentological studies, six lithofacies were recognized: matrix-supported massive conglomerate, matrix-supported conglomerate, clast-supported massive conglomerate, clast-supported crudely bedded conglomerate, horizontal bedded coarse to fine-grained sandstone, and massive coarse to fine-grained sandstone. The lithofacies associations of Gmm, Gmg, Gcm, and Sm are related to sedimentary gravity flow architectural elements and the lithofacies associations of Gh and Sh are related to channel-fill sandstone bodies architectural elements deposited in alluvial fan and braided fluvial systems. Petrographically, the Kerman Formation's conglomerate is categorized as a petromict conglomerate, and the sandstone is divided into volcanic arenite and feldspathic litharenite petrofacies. Gravels are made up mainly of basalt and andesite, as well as fewer limestone and agglomerated tuff. The sandstone plot on the QtFRF suggests that the sandstone of the Kerman Formation derived from volcanic lithic fragments. Geochemical analysis indicates a volcanic arc source area in an active margin tectonic setting, which can relate to the Sabzevar oceanic closure (a branch of Neotethys) volcanic activities. Low values of the Chemical Index of Alteration suggest cool and arid climate conditions alongside a near absence of intense alteration and recycled materials.
Cretaceous volcanic rocks are extensively developed in the Alborz structural zone, located in northern Iran. The petrogenesis and evolution of the northern Alborz basalts and other volcanic rocks have been studied before, but various theories have been proposed regarding their petrogenesis and geodynamic settings. To further explore their petrogenesis, we are conducting a study featuring three different regions of the northern Alborz dominated by extensive outcrops of Cretaceous volcanic rocks. The study area consists of the southern part of Amol city, JavaherDasht village in the east of Gilan province, and south of Lahijan in NarenjLengeh village in the west of Gilan province. Petrographic examination of the studied rocks shows evidence of primary magma, indicating the presence of alkaline magma in the region. Feldspathoids such as nepheline and nosean dominate most samples, providing evidence of alkaline magmatism. All analyzed samples from these three regions fall within the alkaline series. Geochemical studies point to a rift tectonic with significant crustal contamination. In a spider diagram of incompatible elements, an increase in the Nb/La ratio indicates crustal contamination, which is generally observed in continental rifts. All samples exhibit depletion of Y, confirming intraplate magmatism within the region. Chondrite-normalized rare-earth-element (REEs) patterns show a notable enrichment in light REEs (LREEs) relative to heavy REEs (HREEs). Our study suggests a rift tectonic setting for the northern Alborz rocks with prevalent alkaline magmatism during the Cretaceous.
Khomain deposit is situated in the western north part of the Sanandaj-Sirjan belt in western Iran. The main host rocks of the mineralization zone are shale, sandstone Jurassic to lower Cretaceous limestone. Main mineralization deposit includes galena and sphalerite minerals in Khomain. In this research, 170 samples from 33 boreholes were selected to determine the possibility of Pb and Zn anomalies. Lower geochemical anomalies determined by statistical and multifractal models. The Lepeltier, composite halo, factor analysis, original singularity and weighted singularity models were used to identify three dimension anomaly. The coefficient of areal association (CAA) is used to determine similarity of results of different models and is 0.90 and 0.61 for Pb and Zn in weighted singularity model. It indicated that Pb and Zn were confirmed by weighted singularity model in three dimensional studies. Therefore, it can be said that weighted singularity model is suitable relative to other models in identifying weak anomalies. It was determined that the mineralization has a northeast-southwest trend based on the weighted singularity models and is matches with the trend of faults in the mineralization place.
The present study conducted a geochemical analysis of the core sediments from the Jouybar and Zaghmarz areas located on the South Coast of the Caspian Sea in northern Iran. The aim of the study was to investigate the paleoclimate conditions and recycling effects of these sediments. The cores, named AZS (Azad University Shorsahra area) and AM (Amirabad), have depths of 9.3 m and 8.2 m, respectively. They consist of three lithological units, including sandy mud, mud, and silty sand. A total of 50 samples were collected from these units for X-ray diffraction (XRD), geochemistry (ICP-AES), and radiocarbon analyses. The X-ray diffraction analysis revealed that the samples predominantly composed of clay and non-clay minerals (e.g., Quartz, Feldspar, and Calcite). Various chemical indexes based on major and trace elements were used to assess the intensity of weathering. The results showed that sandy mud and muddy sediments experienced slightly higher weathering compared to silty sand sediments, indicating a weak to moderate degree of chemical weathering in the source region. Additionally, the A-CN-K and SiO2 vs. (Al2O3+K2O+Na2O) plots supported the conclusion of weak to moderate chemical weathering in arid and semi-arid paleoclimate conditions. Furthermore, the index of compositional variability (ICV) and the relationships between Zr/Sc and Th/Sc ratios suggested that sedimentary recycling in the core sediments was negligible. Binary plots of V/Cr vs. U/Th and Ni/Co vs. U/Th indicated that dysoxic/oxic conditions predominantly prevailed during the deposition of the two cores' sediments.
The middle Eocene-early Miocene deposits have been sampled in the stratigraphic sections of Isa Abad and Imamzadeh Gahroo, Chaharmahal, and Bakhtiari, to determine the sedimentary environment based on microfacies analysis. Nine carbonate microfacies have been identified based on microscopic studies, where the inner, middle, and outer ramps are located in three facies belts. In the inner ramp, the MF1 and MF2 microfacies indicate an enclosed lagoon considering the presence of perforate benthic foraminifera in huge numbers, corallinaceae algae, ostracods, gastropods, and peloid. Also, the MF3 and MF4 microfacies indicate a lagoon with free water rotation and the absence of a continuous reef due to the simultaneous presence of perforate and imperforate benthic foraminifera. In Shoal (Microfacies MF5), bioclasts and ooids are the major grains, along with peloids, intraclasts, corallinaceae algae, echinoids, bryozoans, and corals. In the middle ramp (microfacies MF6 to MF8), considering the presence of large hyaline species (Lepidocyclina, Miogypsina, and Nummulitidae), the stretched shape of these species, the large size of the allochems, their association with corallinaceae algae, the diversity and abundance of species, the small presence of planktonic and porcelaneus species are evident. In these sections, the outer ramp (Microfacies MF9) can be identified by the presence of planktonic species, the small number of benthic species, and the abundance of the matrix. Due to the gradual conversion of microfacies into each other, the lack of abundance of shoaling ooid and peloid microfacies, and the absence of turbidities and collapse breccia's, the sedimentary environment of these deposits can be attributed to a homoclinal ramp.
The article describes the method used in experimental petrological studies of rock-forming mineral solid solutions. It describes in detail the concept of initial preparation of the materials. The article presents the description of the piston-cylinder type apparatus used in our experimental studies. Such equipment is suitable for the synthesis of high-pressure phases of the silicate systems with the pressure values up to 4.0 GPa and the temperature up to 1700 degrees C. The article also presents the details and describes special features of our method of conducting experiments with the piston-cylinder apparatus. To synthesis the phases the obtained homogeneous glasses are used which determine the equability of the substance distribution. It is revealed that the high-pressure cells made of sodium chloride are more suitable then the water-containing and silicate-containing ones usually used in similar experiments. The analytical methods applied to the obtained data analysis are also outlined.
This study focuses on delineating the potency of geothermal energy within part of the Middle Benue Trough (MBT) via analyses of airborne geophysical datasets. The integrated analyses of airborne magnetic and radiometric data is to foster collaborative imaging and enhance the localization of target resources. A spectral analysis was performed on the total magnetic field of the study area to reveal the essential parameters that could be indicators of a potential geothermal reservoir. The analysis evaluated Curie point depth (CPD), geothermal gradient (GG), and heat flow (HF). Estimated values of CPD, GG, and HF range from 10 to 22.65 km, 25 to 55 degrees C/km, and 60 to 140 mW/m2, respectively. Also, radiogenic heat production (RHP) range from 1.13 to 6.40 mu W/m3 was evaluated via analysis of airborne radiometric data. The RHP was estimated with respect to the lithologies in the study area. Sampling of element concentration and heat generation revealed that granitic rocks, schist, and shale hosted more radioelements and consequently contributed more to RHP within the study area. Viable HF and RHP for geothermal resources were observed at the mid-portion of the northern region, corresponding to Mada, Nasarawa Egon, Akwanga, and at the western and south-eastern edges, covering Udeni and Keana. The delineated major structures in NE-SW direction might serve as migration conduits and channels for crustal HF within the study area. The regions of high HF coincide with those of anomalous RHP, which might be attributable to the geological stability of the study area. This agreement is of priority and interest for geothermal exploitation in the study area.
In the northwest of Iran, in the Sanandaj-Sirjan zone, type A granitoid masses related to the Late Neoproterozoic-Lower Cambrian (Ajab Shir rhyolites, Chaipareh, Mahneshan, Misho, Saqez and Sufi Abad), Mesozoic (south of Dehgolan, Ebrahim-Attar), Cenozoic (Harris and Takab) exist. In terms of geochemical characteristics, the granitoid rocks of Late Neoproterozoic-Lower Cambrian time show the characteristics of magmas related to volcanic arcs, which were formed due to a tectonic window (SCLM) in the final/post-pan-African orogeny stages. In other words, the magmatism of the active continental margin of Cadomin in Iran occurred after the main phase of Pan-African orogeny and simultaneously with the stretching of the continental crust in the Arabian-Nubian shield. But the granitoid rocks of the Mesozoic era (Late Triassic- Early Jurassic) were formed by Paleo Tethys subsidence. Cenozoic (Eocene) granitoid rocks were formed in a tensile environment after the collision of the Arabian and Eurasian plates. Most A-type granites are peraluminous, rich in iron and show enrichment of LREE elements compared to HREE. Also, the amount of MgO, CaO, Sr, Ba, Nb-Ta and Eu is low in them. Most of the granites of Sanandaj-Sirjan zone are located in the A1 range, but some are also located in the A2 range, which is due to metasomatism by fluids originating from the oceanic crust or slab-derived melts. All these granites were formed in a tensile environment.
