مجله پژوهش های دانش زمین
پیاپی 55 (بهار 1403)

The Syahoo salt dome is in the north of Bandar-Abbas in Hormozgan province and structurally it is located in the geological zone of the Zagros. Potash prospecting studies in the south of Zagros have identified the Syahoo salt dome as an important area. Some of them, such as Angore, are currently active and there is still salt extraction in them, and in some, such as Pahl, Kouh Namac, and Siha, the salt extraction has been completed or is in the final stages. The purpose of this research is geological, remote sensing and geochemical studies on potash mineralization along with salt domes, which can be a potential for this type of deposits in southern Iran.

In order to find the areas of accumulation of potash mineral in the area of ​​ Syahoo salt dome, satellite images of ASTER were first used to identify promising mineral areas for sampling and geochemical studies. Then, based on remote sensing studies, sampling was done for XRF, XRD chemical analysis.

In order to identify rock units and areas containing salt and iron oxide, ester satellite images and methods of false band composition (RGB), spectral angle mapper (SAM) and principal component analysis (PCA) were used. The results of these studies show that all three methods have worked well in highlighting iron oxide areas and areas containing salt and show a good agreement with the geological map. Meanwhile, the spectral angle mapper method has better and higher accuracy. The results of remote sensing studies show that the west and east areas of the Syahoo salt dome contain a higher potential for potash mineralization. Also, in order to determine the potassium mineral, 17 samples were chemically analyzed by XRD method; the results show that potassium mineral was sylvite.

According to the geological, telemetry and geochemical studies, the grade of potash in many parts of the Syahoo salt dome, such as north, south and south-east are of less than one percent and have no exploratory value. Based on the studies, the proposed areas for exploration will be limited to the west (Target 1) and east (Target 2) of the salt dome. The highest grade of potash is related to the samples of the western part of the salt dome, on the other hand, secondary potash is also observed in this part; therefore, more attention has been paid to the potential of the western part. Based on the results of geochemical analysis, the western edge of the dome shows a high potash potential compared to other areas of the dome. The highest grade of potash in this section is 16.6%. The small outcrop of potash in this ridge and its low expansion in this section, with an average grade of 2.4%, makes this ridge the second priority, the highest grade of potash in this section is 10%.

Fault interaction creates areas of local concentration of stress and disturbances that affect the geometry and cognitive movement of faults. This stress concentration can create secondary structures in damage. In this article, the influence of the interaction or relationships between the Zagros and Arabian faults in the Zagros foreland on the formation and different geometry of the Rag Sefid and Tango anticlines is investigated and explained.

Due to the occurrence of the phenomenon of fault interaction between the faults that cause the Rag Sefid and Tengo anticlines, the three-dimensional interaction theoretical models between the fault segments are first introduced. By comparing the geometrical condition of fault parts in the study area with theoretical models, the types of fault interaction in this area are introduced. Finally, due to the dependence of the folds in the region on the fault, and with a detailed study of the geometry and dimensions of the underlying faults, the factors affecting changes in the pattern of folds are examined and the development of folds with different geometries, dimensions, extensions and mechanisms is justified.

Regarding the length more than 3 times of the Rag Sefid fault respect to the southern part of the Hendijan-Izeh strike-slip fault, the mean slope of 47 degrees of the Rag Sefid fault relative to the Hendijan-Izeh fault of 80 degrees and according to the general compression direction of N22E in the Southwest of Iran and the southern part of the Hendjan-Izeh fault trend (N20E), as well as the Rag Sefid fault trend, which is approximately perpendicular to the general compression direction, the deformation amount of the Rag Sefid fault is more than the Hendijan fault. In this condition, the stress field of the Rag Sefid thrust fault is dominated and due to the less resistance of the rising, folding with a larger amplitude occurs on the the Rag Sefid anticline; so that the folding amplitude in the Rag Sefid anticline is more than twice as large as the Tango anticline, and the tip of the Tango anticline is about 1,200 meters lower than the Rag Sefid anticline.

It can be concluded that in a set of faults where the interaction between the faults has occurred, larger, shallower faults with a plane slope of about 45 degrees, which have a diagonal or vertical orientation compared to the general orientation, they can create large and clearer folds similar to the folds with large dimensions in the Rag Sefid anticline compared to the Tango anticline.

The Cretaceous system includes carbonate sediments and covers a large part of Zagros. Gadwan and Darian formations are located in the upper part of Khami group. These formations have been investigated by many researchers in several terms. The purpose of this study is to investigate the biostratigraphy of Gadwan and Darian formations, as well as to identify sedimentary facies to reconstruct their paleo-environment.

In this study, thin sections were prepared from cores and cutting and examined with a microscope. A microscopic study was done to identify microfossils (Loeblich and Tappan 1988). Also, skeletal and non-skeletal elements and microscopic characteristics were determined (Flügel, 2010). These were named according to Dunham's method (1962).

Biostratigraphy in Well A: 1) Choffatella decipiens - Pseudocyclammina littus -Trocholina elogatus assemblage Zone. It is introduced from the depth of 4740 m (the lower limit of Gadvan Formation) to 4623 m.
2) Mesorbitolina texana - Choffatella decipiens assemblage Zone. This zone is introduced from the depth of 4623 m to 4552 m.
Biostratigraphy in Well B: 1) Choffatella decipiens - Pseudocyclammina littus -Trocholina elogatus assemblage Zone. Zone No. 1 is introduced from the depth of 4860 m (the lower part of Gadvan Formation) to 4744 m.
2) Mesorbitolina texana - Choffatella decipiens assemblage Zone. This zone is introduced from the depth of 4744 m to 4677 m.
Facies of Darian Formation (Well A): MF1) Mudstone. This facies is associated with deep basin microfacies.
MF2) Planktonic Foraminifora Wackestone. This microfacies represents the low-energy environment.
MF3) Bioclastic Planktone Foraminifora Packstone. The presence of micrite indicates a low energy zone.
Facies of Gadvan Formation: MF4) Bentic Foraminifera Bioclast Packestone. It indicates a high salinity and indicates a lagoon.
MF5) Bioclastic Wackestone. It indicates low-energy environment of the middle ramp.
MF6) Mudstone. This microfacies represent a lagoon environment.
Facies of Darian and Gadvan formations (Well B)
Facies of Darian Formation: MF1) Mudstone. The facies formed in the outer ramp.
MF2) Planktonic Foraminifora Wackestone. The facies deposited in a low-energy in the external ramp.
MF3) Bioclastic Plankton Foraminifora Wackestone. The facies deposited in the outer ramp.
MF4) Orbitolina Peloid Packstone. The facies indicate an environment with high salinity in shallow waters and in the lagoon environment.
MF5) Bioclastic Wackestone. The facies deposited in the middle ramp.
MF6) Mudstone. The facies composed of micrite and has less than 10% bivalves and bryozoans.

Sedimentary environment: 

These facies were deposited in the marine environment and in the outer and middle ramp and a small part of the inner ramp.

In order to study the depositional environment of Gadvan and Dariyan formations in Gachsaran oil field, thin sections have been studied. Based on the biostratigraphy data, the age of Barremian to Aptian for Gadvan and late Aptian for Dariyan was considered. Microfacies study of Dariyan and Gadvan formations led to recognition of 6 microfacies in 3 facies belt, Inner ramp, Mid-ramp, Outer ramp in marine environment. Also, based on variation of microfacies, the studied area predicted as hemoclinical carbonate ramp.

The Niaz Cu prospect is located 25 km west of Meshkinshahr, east of the Qaradagh metallogenic zone. The intrusion Oligo-Miocene magmatic bodies into the Paleocene-Eocene rock units has led to alteration and mineralization. The rock units of this area include batholiths Ι and ΙΙ (Khanbaz granodiorite and Khankandi granodiorite), Niaz quartz-monzonite/ quartz-monzodiorite and ore-bearing rhyodacite breccia.

In this research, the geological features, alteration, mineralization and physicochemical conditions of mineralizing fluids have been studied. In this regard, sampling from altered, mineralized zones and drilling cores were carried out and 23 samples were analyzed by XRF and 18 samples by ICP-OES methods and microthermometric measurements were performed on 8 doubly-polished thin sections.

The intrusive units have high-K calc-alkaline to shoshonitic nature, and the geochemical characteristics of their trace elements indicate similarities with subduction-related magmas. The negative anomaly of Ti and Nb in these rocks can be due to the magmatism related to the subduction processes, as well as the stability of the phases containing these elements during partial melting or their separation during the differentiation process. The enrichment of Pb, La, K, U, and Th elements and the depletion of Sr, Ti, and Nb can be attributed to crustal contamination. Hypogene alterations at Niaz include potassic, phyllic, propylitic and intermediate argillic types. Mineralization has occurred during early, middle, and late stages. Based on the mineralogy and paragenetic sequence, at least five types of veins/veinlets can be distinguished in Niaz deposit. Group A veinlets contain quartz+pyrite+chalcopyrite+magnetite, group B veins are also present in the potassic and phyllic alteration zones, veinlets of group C are mainly formed in the middle stage of mineralization, group D veins are mostly observed in the phyllic alteration zone, which are formed in the middle and later stages of hydrothermal activities and group E veins are almost devoid of sulfide minerals and mainly contain bright-color minerals (quartz and/or calcite)±tourmaline and are mostly present in the propylitic alteration zone. Studies on fluid inclusions (FIs) within the quartz veinlets showed that there are four types of FIs at room temperature, (1) mono-phase vapor, (2) liquid-rich 2-phase, (3) vapor-rich 2-phase, and (4) multi-phase solid containing daughter solid phases. The ranges of FIs are about 280-360°C in the potassic, 280-360°C and 280-300°C in phyllic and 170-330°C in propylitic alteration zones.

The petrology and petrogenesis of magmatic host rocks, mineralogy, hydrothermal alteration in the Niaz area testify to a porphyry-type Cu mineralization. The main sulfide mineralization includes vein-type pyrite, molybdenite, chalcopyrite, sphalerite and galena. Fluid inclusion microthermometry results show a Th range of 170-360 °C and salinity values of 0.2-60 wt%NaCl equiv., corresponding to the ranges of porphyry Cu deposits. Boiling and simple colling of ore-bearing fluids were the main processes for ore precipitation.

Since the Garau Formation is important as a source rock in the Zagros sedimentary basin, in this research, tried to identify and introduce microfacies, sedimentary model, and sedimentary geochemistry of this formation in Aligudarz section located in the southeast of Lorestan.

Aligudarz section (southeast of Lorestan) is located in the high Zagros zone and in the geographical range of north latitude 33°04′05″ and east longitude 49°00′17″. To identifying microfacies and sedimentary environment, 235 thin sections were prepared and studied. Also, 40 samples were analyzed by atomic absorption spectrometer (AAS) to determine the range of values of major and minor elements (Ca, Mg, Sr, Na, Mn, and Fe).

The Garau Formation thickness in Aligudarz section is 483 m, and lithology consists mainly of limestone, shale and shaly limestone. The lower boundary of the Garau Formation with brrecia limestones is equivalent to the Gotnia Formation in the form of unconformity and the upper boundary is not clear due to its location in the syncline core. Study of this section microscopic sections led to the identification of 7 microfacies in the deep-sea facies belt. Based on the major and minor elements and the ratio of these elements to each other, original mineralogy composition has been mainly aragonite and have been affected by two types of dissolution in closed and open systems. And also has anoxic conditions or an increase in the effect of meteoric diagenesis. The original mineralogy composition has been mainly aragonite and have been affected by two types of dissolution in closed and open systems. Due to anoxic conditions or an increase in the effect of meteoric diagenesis.

Thickness of this section is 483 meters, and lithology consists mainly of limestone, shale and shaly limestone. The lower boundary of the Garau Formation with brrecia limestones is equivalent to the Gotnia Formation in the form of unconformity and the upper boundary is not clear due to its location in the syncline core.The most important biological components identified in different parts of the Garau Formation include radiolarian, planktonic foraminifera (Globigerinelloides, Hedbergella, Leupoldina). Among the most important non-carbonate compounds are iron oxides.The Garau Formation is formed in the deep-sea facies belt belonging to a ramp-type carbonate platform. The original mineralogy has been mainly aragonite and have been affected by two types of dissolution in closed and open diagenetic systems, possibly due to anoxic conditions or an increase in the effect of meteoric diagenesis

Evapotranspiration is one of the important components of water balance. Estimation of evapotranspiration has been the focus of many researchers in Iran and the world. Accurate estimation of evapotranspiration is very important in hydrological modeling, irrigation design, and water resources management. This variable is one of the most important and effective components in the water balance. Evapotranspiration after rainfall is considered the second largest component of the earth's water cycle on a global scale. The assessment of the future climate and climate change and its effects is done through the output of climate models.

In this research, the average daily minimum and maximum temperature data were scaled according to the CanESM2 model under RCP scenarios using the SDSM for 6 synoptic stations in the southern part of the Aras River basin to draw the perspective of ETp using the Hargreaves-Samani method until the 2050s. For this purpose, observational data of stations and reanalysis data (NCEP) in the daily period (1985-2005) as well as historical data of the CanESM2 model (historical-2005) under RCP scenarios (for the period 2006-2100) has been used.

Estimated ETp values for the Aras basin during the coming period based on the downscaled temperature data of the CanESM2 model under RCP scenarios showed that the value of this variable under the RCP2.6 scenario compared to the base period, slightly decreased and under the RCP4.5 and RCP8 scenarios will have a slight increase. The amount of ETp in this basin will have a decreasing change in the Ardabil, Ahar, and Khoi stations and an increasing change in the Pars-Abad and Jolfa stations. The monthly ETp value of the Aras basin in the future period in January, April to June, and August was estimated to increase with a range between 0.1 to a maximum of 24.3 mm compared to the base period. Comparing the estimated ETp values of the future and the past period showed that the ETp estimated by the Hargreaves-Samani method in the past period compared to the evaporation data of stations except Pars-Abad and Khoi was overestimated by more than 100 mm per year, and it was less in other stations. Hargreaves-Samani ETp values, except for Mako, which is higher from 1985 to 2005 than in 1992-2005, in the other stations in the period of 1992-2005 are greater than the values of the base period.

The estimated ETp values for the Aras basin during the coming period showed that the value of this variable at the annual basin level will increase slightly compared to the ETp of the base period (by the Hargreaves-Samani method), which means that the water requirement of plants will increase in the future in the growing season and this increase means an increase in the water requirement of plants in the future in the growing season, a decrease in infiltration and an increase in evaporation of water resulting from rainfall and snow melting, and a decrease in the feeding of aquifers.

As a result of the problem of pollution in the metropolitan areas and the amount of energy consumption, the effort to solve this problem is that it can be identified as the introduction of systems and models to replace the systems and the existing models of energy supply. In this research, quantitative modeling for energy in Tehran metropolis is considered according to environmental, economic and climatic goals.

In this research to analyze the collected data from experimental and quantitative methods and analytical software GIS and Windographer have been used. To better process the solar radiant energy status, a series of radar images from the PALSAR sensor from the ALSO satellite were selected and processed and solar energy modeling was performed using the Area Solar Radiation model.

Solar Energy: Due to the radar analysis process, Palsar radar images were obtained from the JAXA database. DEM radar images were used in ArcGIS software, in which the initial operation was performed. After converting the desired images into a single image, the image of the study area was extracted from the radar image. Finally, to create a better view of the study area, a map of the solar energy has been prepared. This map shows us in which areas of the region there is more possibility to use solar energy and in which areas this possibility is less. In the metropolis of Tehran, the northern half of the study area has more potential to use radiant energy.

Wind energy:

 In order to obtain a general of the situation in the region, wind energy potential in sample stations including: Chitgar, Firoozkooh, Geophysics, Imam Airport, Mehrabad Airport and Varamin has been calculated. Analysis of data related to wind energy in the region showed that the western and southern regions have the most potential for wind power generation capacity in the metropolis of Tehran.
Biomass energy (municipal waste): Today, biomass is recognized as one of the world's largest renewable energy sources. One of the types of biomass compounds is municipal waste. The amount of waste produced in Tehran is more than 7600 tons. The analysis of the obtained data showed that due to the huge volume of daily waste production in the metropolis of Tehran, with optimal modeling and proper planning, a good renewable energy source can be achieved for the region.

In relation to modeling, according to the obtained results, the model was created based on three groups of renewable energy, including solar energy, wind energy and biomass (municipal waste). To provide an integrated model for the Tehran metropolis, solar, wind, and biomass (municipal waste) data had to be analyzed on the same scale. Therefore, in order for the solar, wind and biomass energy data to have the same scale, first these data were evaluated using multi-criteria evaluation and then these values to have the same scales, the fuzzy membership function was used. Finally, the final output of the model will be in the form of a zoning map, in which there are three groups of energy (solar, wind and biomass).

Coastal land use changes of Qeshm Island can have different reasons that haven’t been investigated. Researchers have used images by medium resolution, especially RS with pixel 30m. in this research, a series of high-precision aerial photos with scales of 1:10,000 and 1:20,000 were used to extract patterns of coastal land use for the 51 years ago. The goals are investigation of coastal land use changes of Qeshm Island during the last half century.

The study area was defined in a buffer of 2500 m from the coastline to the land side of Qeshm Island, and the beach use patterns in this area were investigated and analyzed. At first, information sources were used to extract the coastline and determine the study area, by aerial photos of Qeshm Island in the years of 1346, 1369, 1374, 1386 and 1396. The aerial photos were ground-referenced and existing borders and land uses. In order to predict the area of ​​man-made use and its relationship with geographical effects and environmental criteria in the coastal areas of Qeshm Island, a geographically weighted regression model was used.

The results showed that barren lands, rocky hills and scattered forests are the dominant patterns of Qeshm coastal land use with relative frequency of 29.3%, 23.7% and 10.3% respectively. In the years 1346 to 1396, barren lands, agriculture, rocky hills, mangrove forest and coastal rocks have decreased by 4851, 297, 7099, 219 and 2938 hectares respectively; However, human settlements, Tepe Mahor, clay beaches, sandy beaches, wharf-ports and industrial areas have increased by 2094, 3813, 136, 5351, 644 and 1249 hectares, respectively. In the eastern areas, especially the Darghan-Qeshm axis, the most coastal land use changes related to human constructions include the construction of the Tula industrial town, the development of Qeshm and Darghan urban settlements, the construction of Bahman and Zakari wharves, the development of Darghan city and the Laft wharf. The area of ​​the coastal city of Qeshm on the east coast increased from 450 ha in 1386 to 730 ha in 1396 and the growth of the city has been towards the south and southwest. The geographically weighted regression model showed that with the variables of distance from natural habitats, distance from protected areas, beautiful coastal views and distance from the port, the area of ​​man-made use in the coastal areas of Qeshm Island can be predicted.

Analysis and review of aerial photos of Qeshm Island in the coastal area 2500 meters wide from the coast line in 1346 to 1396 in a period of 51 years showed the use of barren land that lacks forest cover. are, rocky hills and thin and scattered forest covers are the dominant uses of the coastal areas of Qeshm Island; But the planning, policies and development of the ecotourism industry as well as the capacity of marine and energy industries lead to human development and industrial, commercial and residential constructions in the coastal areas of Qeshm, especially in the year 1374 to 1396.

Climate change has had irreversible effects on the planet Earth. The impacts of these changes are observable in all natural and human phenomena. One of the affected phenomena by climate change is dust storms. Besides their short-term and long-term effects, these storms significantly influence air quality on both local and global scales. In recent decades, the frequency of dust storms has increased due to climate variations and human activities, and it is predicted that this increasing trend will continue in the future. Investigating the effects of climate change on dust storms in Southwest Asia, as one of the most significant dust storm hotspots globally, holds great importance. The objective of this research is to examine the impacts of climate change and forecast dust storms in Southwest Asia using the GRDL-ESM4 model from the CMIP6 model ensemble under the optimistic scenario (SSP1.2.6) during the near-future period (2021-2060).

Southwest Asia is located in the global desert belt. The intensification of climate change in this region has distinct impacts on the trends of dust storms, especially mineral dust storms. Therefore, this study focuses on forecasting dust storms in Southwest Asia using the CMIP6 model ensemble, specifically the GFDL-ESM4 model, under the optimistic scenario (SSP1-2.6). The research methodology involves initially using a 40-year historical period (1975-2014) to analyze dust storm anomalies. Then, the CMIP6 model ensemble, specifically the GRDL-ESM4 model, is utilized to examine the dust storm trends until the end of the present century. Furthermore, the optimistic scenario (SSP1-2.6) is employed for the near-future forecasting period (2021-2060).

The results show that the maximum amount of dust storms occurs during the summer and spring seasons. In the summer season, the significant increase in temperature and decrease in precipitation contribute to the highest level of dust storms. The spring season exhibits a high level of dust storms compared to other seasons, with northern latitudes having more dust storms than southern latitudes. The minimum dust storm occurrence is observed during the autumn and winter seasons. Autumn is characterized by decreasing temperatures and increasing precipitation processes, leading to a reduction in dust storm frequency. In the winter season, the semi-Arabian Peninsula, especially the eastern regions, experiences the highest dust storm occurrence. In the spring season, the eastern part of the Arabian Peninsula, during the summer season, the southeastern regions of the Arabian Peninsula and southeastern Iran, and during the autumn season, the northern half of Arabia and eastern Iran have the highest frequency of dust storms. According to the optimistic scenario, the summer and spring seasons have the highest dust storm occurrence. Furthermore, it is evident that the intensity of dust storm trends will be higher in the southeastern regions of the Arabian Peninsula, the Makran coasts, the northern half of Iran, northern Arabia, and between the rivers compared to other areas.

In general, southern latitudes experience higher levels of dust storms compared to northern latitudes. The primary center of dust storms is located over the Arabian Peninsula in early winter, gradually shifting towards the eastern regions. During this season, the center of dust storms moves from eastern Arabia to southeastern parts of the Arabian Peninsula and southeastern Iran.