نشریه زمین شناسی کاربردی پیشرفته
سال سیزدهم شماره 50 (زمستان 1402)

The Mahura placer magnetite deposit is located in the eastern part of the Miqan Arak sedimentary basin on the border between Urmia Dokhtar and Sanandaj Sirjan structural zones in Quaternary alluvial sediments. Magnetite grains have micron to milimeter in form free grains and also inside the minerals of volcanic rocks found in the alluviums. Based on petrography and mineralogy studies, these mafic volcanic rocks are named , andesite, andesite basalt to basalt, and tiny grains of magnetite are observed inside amphibole and pyroxene mineral grains and at the border between them. According to the microprobe Analysis data of the magnetite ,, this mineral has high TiO2 and is located as a titanomagnetite or a solid solution mineral between magnetite and ilmenite, and according to the diagrams, it is placed in the group of Fe-Ti-V magnetites. The evidence obtained from the chemistry of existing clinoproxen minerals indicates that the source rock of these placers has a calc-alkaline composition and is formed in a continental arc environment , campatible with tectonic setting of Urmia Dokhtar , pressure about 2-5 kilobars and a temperature of 1100 degrees Celsius and depth between 7 to 10 km are condition to form this rocks. High content of iron-titanium, high amount of water about 10%, high fugacity of oxygen according to FMQ+1.5 system, are among the most important factors that caused immicibility and partial crystallization of magma oxide liquids and the formation of magnetite grains in the source rock of this deposit.

In this article, artificial intelligence methods and geological evidence were used to identify promising areas for gold mineralization. Gold grade values in the Zailik prospecting area located in the northwest of Iran were estimated by two artificial intelligence methods, artificial neural network and its integration with particle swarm optimization algorithm, and the type of constituent rocks and alterations of the studied area was chosen as geology parameters. After the summary of expert opinions in geosciences and mining, the geological parameters were weighed, and to score the artificial intelligence methods for estimating gold geochemical values, the coefficient of determination and the root mean square error function were used. All these methods were compared to the analytical hierarchy process (AHP) in expert choice software. The highest score among geological parameters, after summarizing expert opinions related to lithology and also among artificial intelligence methods, due to the higher coefficient of determination and lower error function, is the combined method of artificial neural network with particle swarm optimization algorithm was awarded. Finally, in the Arc Gis software, all the mentioned methods are united by the fuzzy overlay method. According to the final presented modeling, the northern and northeastern parts of the reconnaissance area are considered areas prone to gold mineralization to continue exploration was suggested.

Source candidates for the Middle Cretaceous – Early Oligocene petroleum system in the Chilingar oilfield were geochemically evaluated using Rock-Eval pyrolysis and vitrinite reflectance measurements, along with taking matrix retention, inert OM and maturity effects into account. Moreover, the gas-oil ratio potential (GORP) factor was used to split the average live TOC and S2 parameters into the oil-prone and gas-prone constituents. Based on the results, Pabdeh and Gadvan formations have the highest and lowest hydrocarbon potential, respectively. According to the S2 vs. TOC diagram, the mineral retention effect and inert OM content are negligible for the Pabdeh formation. On the contrary, Kazhdumi and Gadvan samples show a significant mineral matrix effect and inert organic material, resulting in a substantial reduction of the hydrogen index and lower apparent quality. Based on the corrected-original parameters, Kazhdumi and Gadvan formations are categorized as mainly oil-prone and gas-prone source rocks, respectively. However, these formations show a low-to-fair quantity of live OM, due to the activities of the Khark-Mish paleo-high during the Cretaceous. In terms of thermal maturity, Pabdeh and Gurpi samples are immature, but Kazhdumi, Dariyan (the upper shaly layers) and Gadvan formations have entered into the preliminary stages of the main oil generation phase. Indeed, insufficient maturity of the source candidates (maximum Ro: 0.72) could be considered as a possible reason for the absence of hydrocarbon reserves in the Asmari and Bangestan reservoirs of the Chilingar oilfield.

Urbanization and the increase of impermeable materials cause significant changes in the thermal properties of the region, which leads to the creation of urban thermal islands, on the other hand, the change of use caused by human activities leads to adverse effects on the region's environment. Plains areas are a clear example of these phenomena. The purpose of this study is to analyze the spatial and temporal changes of land use/land cover and its effects on the surface temperature of the plains of Dezful city. Landsat images in 2000-2020 were used to analyze the changes of (LU/LC) and its thermal bands to investigate LST using remote sensing techniques. Significant changes in land use were observed in this fertile plain during the study period. The highest percentage of land use change was related to the change of barren to agriculture and gardening, the second percentage land use change of water use to agriculture and gardening. During the monitoring period of 151,189, water areas decreased to half of 66,712 hectares. urban areas increased almost twice from 97,462 to 174,713. The Land surface temperature has increased during the monitoring period, the average temperature has increased in all classes of land use, but temperature increase in urban and barren classes are more than agricultural and gardening classes. The vegetation cover index increased during the monitored period, but this increase was not enough to prevent the temperature increase.

The early-mid Cretaceous carbonate sequences in the northeast of Rafsanjan city contain abundant and diverse foraminifera assemblages. A stratigraphic section of these sequences has been sampled for biostratigraphical and paleoenvironmental studies. The studied section was subdivided into two informal lower and upper units based on lithological characteristics. The former is composed of coloured marls intercalated with a few limestone intercalations. Planktonic foraminifera, oligosteginids and radiolarian are most components of it. The upper unit consists of fossiliferous limestones with intercalation of marls, rich in benthic foraminifera and calcareous algae that form cliff walls. The lower unit is characterised by r-selected hedbergellids, reflecting nutrient-rich/eutrophic marine environments. Whiles an abundance of cone-shaped orbitolinids, calcareous algae, and invertebrate organisms (echinoids, corals, and Mollusca) reflect deposition in the photic zone of shallow water marine platforms with stable temperature and salinity conditions. The biostratigraphic data allow us to date the Lower Cretaceous successions between Barremian and probably the early Cenomanian. One planktonic and five benthonic foraminiferal biozones are identified which include:Hedbergella spp. Assemblage ZonePalorbitolina lenticularis ZonePraeorbitolina spp. Assemblage ZoneMesorbitolina parva ZoneMesorbitolina texana ZoneMesorbitolina subconcava Zone

In order to manage water resources, it is necessary to know the current situation of the resources and predict it in the future .In this research, in order to investigate the nutritional effects of irrigation and drainage network of Gaveshan Dam in wet and dry periods on underground water resources of Myandarband plain, after collecting geological, meteorological, hydrological and hydrogeological information, geophysical tests and exploratory boreholes, rainfall statistics and the level of the underground water level in the discharge wells and the construction of a conceptual model, simulation, calibration and verification of the underground water level were done using the GMS10.1 software. The results of the calibration of the model indicate a very good fit of the observed and calculated water level data of the model with R²=0.99. According to the recalibrated model, the effects of return water from the irrigation and drainage network of Gaveshan Dam in two periods, wet and dry, which were determined through the trails test, were predicted with the percentage of infiltrations of 10, 20 and 40% for the spring season of 2016. The results of the research clearly show the positive effect of the construction of irrigation and drainage network on the increase of the underground water level, as well as the difference of the positive effect in wet and dry conditions.

In this research, we investigate the seismic hazard associated with the Kheyrabad blind thrust fault at the north of Birjand, Eastern Iran. Field measurements from a structural transect through the Kheyrabad anticline indicate fault-propagation folding above a 38° northeastward-dipping blind thrust fault which probably reaches into a horizontal detachment at a depth of ~500 meters. In this research, in order to evaluate the seismic risk of Khayrabad blind fault have been investigated, parameters such as average slip rate, maximum earthquake (Mmax) and its recurrence. Obtaining estimates of the slip-rate on the blind fault, and of the rate of crustal shortening are difficult, but we assume that transport of material on the horizontal decollement at depth is balanced by extrusion of material at the surface, we can produce approximate measurements of slip-rate and shortening by using area balancing. In this method, the rates of fault slip, horizontal shortening, and uplift have been estimated as 0.75, 0.59, and 0.46 mm/yr, respectively. Using the regression equation between earthquake magnitude and rupture area, magnitude of the maximum earthquake is estimated at 4.7. Also, using the empirical relationships between magnitude, coseismic displacement and slip rate, the recurrence of this earthquake is predicted to be 577 years. According to the obtained slip rate (0.75 mm/yr), the activity grade of Khairabad blind fault is considered moderate.

The Sarkuh porphyry Cu deposit located in the Urumieh – Dokhtar Magmatic Belt (UDMB), is associated with the emplacement of Miocene intrusions mainly containing granite – granodiorite within Eocene units including tuff, andesite, basaltic andesite, and pyroclastic breccia. Potassic alteration of the deposit (dominated by magnetite, secondary and re-equilibrated biotites as well as anhydrite) is well extended. In this study EDX spectra of accessory minerals within potassic alteration was assessed to trace the occurrence of rare minerals. Additionally, EMPA results of magnetite paragenesis were linked to physicochemical attributes of rare minerals occurrences. Results indicate that unusual occurrence of Ce-La rich epidotes with REE-enriched monazites and Ce-bearing titanites are accompanied with apatite, anhydrite, hydrothermal biotite, quartz, and magnetite assemblages in the potassic alteration. Magnetite composition implies that early-stages high temperature magmatic – hydrothermal fluids (>500 °C) with low rates of fluid – rock interaction were contributed in the magnetite crystallization. Commonly, these magnetites are accompanied by hematite and anhydrite providing insights into the very high oxygen fugacity conditions (near magnetite - hematite buffers ~ ΔFMQ+4). Considering the chemistry of magnetite paragenesis, it seems that the occurrence of rare minerals are mainly associated pre-ore stages in the potassic alteration

Mahin village is located in Alborz-Azerbaijan area in Tarom-Hashtjin magmatic- metallogenetic sub-area. According to petrographic studies done around the south of Mahin, the outcrop rocks include trachyte andesite, andesite, basaltic andesite, pyroxene andesite, pyroclastic, and porphyritic gabbro, affected by the alteration process. In geochemical studies, the samples are located in the basalt, alkaline basalt, andesite, and basaltic andesite domains. All rock samples are in the magmatic series of calc-alkaline to high-potassium calc-alkaline (shoshonite). The primary magma is alkaline in nature. Amphibole and mainly phlogopite have been present in the original melt. Accordingly, the primary magma was probably formed at a depth of about 70 km. The composition of high-potassium calc-alkaline, the decrease of FHSE elements, especially Zr, the high ratios of Nb / U, Th / U, Ba / Nb, Nb / Th, and the low ratio of Ce / Pb and the diagrams all confirm the existence of active continental. Arc island evidence in some diagrams, and the association and simultaneity of igneous rocks with green tufftite and sedimentary rocks in and around the area, all confirm the existence of continental(ensialic) back-arc basin. According to these indications, there might have been active normal continental arcs and ensialic back arc simultaneously in the area.

In comparison with other geological zones of Iran, the Makran geological zone has been studied less. This study aims to introduce and study the Late Cretaceous fossiliferous successions (part of the Chah-Mirak Unit), in the southeastern Kahnuj (the northwestern part of the Iranian Makran geological zone) to draw the geologists’ attention to the area. Given the note that most of the rock units in the region are non-sedimentary (ophiolitic) complexes or Quaternary continental sediments, every fossil evidence is of great value for investigating and reconstructing the paleo-environmental condition of the region. Lithologically, the studied successions mainly consist of tuffaceous limestones, which were deposited after the reduction of pyroclastic material to the basin; its lower and upper contacts are composed of volcanic rocks. The studied successions present different fossil groups such as abundant gastropods, corals, algae, bivalves, and foraminifera. The gastropod-rich sequences and younger marine layers are Cenomanian and Cenomanian-early Santonian in age, respectively. The shallow marine lagoonal environment (accompanied by mollusks, especially abundant gastropods), and slightly deeper settings containing coral and algae, are suggested for the deposition of these successions. Further studies are necessary for a more detailed examination of the fossil groups.

To determine the probability of sewage infiltration into foundations of unborn structures, the Werner and the dipole - dipole arrays were used in an electrical resistivity tomograph operation in Masjed Soleiman City which is located in south west of Iran. Using Robust Constraint and Combined Marquardt and Occam algorithms, the measured apparent data were inverted to true electrical resistivity values separately then joint inversion was carried out using the data gathered by both arrays. Three drilled boreholes along the electrical resistivity profile were very useful in accurate interpreting the results. The Combined Marquardt and Occam algorithm provided better results than the Robust Constraint for presenting a subsurface electrical resistivity mode. Also, the electrical resistivity model resulting from the joint inversion of the Werner and dipole - dipole array data is more consistent with reality than the individual inversion of the data for each array.

The late Triassic metabasites in the southeast of Borujerd area in the middle part of Sanandaj Sirjan zone (SaSZ) are associated with marble and locally intersected by mafic dykes. Metabasites rocks are metamorphosed in the lower green schist facies and are mainly composed of plagioclase and amphibole. However, they locally preserve ophitic and porphyritic igneous textures. The electronmicroprope analysis showed that feldspars are albite, oligoclase and anorthoclase. Also, according to this analysis, type of amphiboles is calcic and includes actinolite, actinolite-hornblend, magnesiohornblend and tschermakit-hornblend to tschermakit. According to geochemical studies, these rocks have alkaline magmas characteristics. The chondrite normalized REE patterns show enrichment in LREE and the Primitive-Mantle normalized multi-element patterns show uniformly enriched LREE, Th, Nb, Ta. These characteristics are similar to those of basalts derived from OIB-like mantle sources. Trace-element ratios, including Ce/Nb (1.22– 2.20), Hf/Nb (0.08–0.2), Zr/Nb (3.63–6) and high TiO2/Yb and Nb/Yb ratios, indicate that these magmas were derived from a deep OIB reservoir, i.e. an enriched asthenospheric mantle source. These rocks underwent slight crustal contamination. These geochemical characteristics of these late Triassic metabasites suggests that they formed in an intra-continental rifting regime.

One of the most important problems in mining is the flow of groundwater into the pit mines. The location and amount of these waters are often dependent on the permeable zones. Therefore, geostatistical methods can be used to identify these zones. Hence, geostatistical research has been done on variable data of the rock quality designation (RQD) to identify permeable zones in the area of Takht e- Gonbad copper mine pit, Sirjan. This mine is located in Kerman province, northeast of the Sirjan city and it is an open-pit type. A total of 69 exploration boreholes have been dug in the area around the pit. During the drilling, the variable data of the RQD was recorded during a spatial distance of 3 m along the entire length of the boreholes. Identifying areas with high permeability in the rock units of the region, especially in the subsurface of the aquifer, is necessary to carry out the drainage plan in the future. In this research, geostatistical simulation methods have been used to identify permeable zones. The results of the preliminary statistics showed that the RQD has an increasing trend with increasing depth. The spatial continuity of the RQD based on the directional variogram and the spherical model was estimated about 81 meters, and was greater in the east-west direction. Finally, by geostatistical simulation, the areas with high permeability in the region have been determined which are mainly located in the northeast and southwest of the pit.

The Fahliyan Formation, located in the Abadan Plain, is one of the most significant productive units in the Zagros Basin. Its Mesopotamian Basin equivalent, the Yamama Formation, also contains large quantities of hydrocarbons. Due to the geochemical similarities of these two reservoirs, investigating trapped oils and correlations can yield significant results. However, there have been limited studies describing the relationship and oil-oil correlation between the Fahliyan and Yamama oil samples. In this study, geochemical analyses such as GC, GC/MS, and stable carbon isotope were used to analyze the Fahliyan oil samples. Furthermore, Yamama data were taken from previously released studies in the Mesopotamian Basin. The results showed that both Yamama and Fahliyan oils were non-biodegraded and mostly paraffinic and light, indicating peak mature or late mature levels. The indices also suggested that the oils had a marine carbonate source with type II kerogen, which was deposited under anoxic and low salinity conditions of the deposition environment. The Jurassic source rock of these reservoirs was confirmed by the geological age biomarkers. Following this and previous research, it was concluded that the Sargelu and Garau (Sulaiy) formations are the most likely source rocks. Investigations of the oil biomarkers and the results of other studies in these areas deduced that the Fahliyan and Yamama oils in study areas are classified in the same genetic family. These results will affect the field development plan.

The Qori metamorphic complex in the northeast Neyriz (Sanandaj-Sirjan zone) formed due to the different metamorphic phases during the Jurassic to Cretaceous as a result of the subduction of the Neotethys oceanic crust beneath the Iran microplate. The whole-rock compositions revealed that some of the complex units formed from the metamorphism of basic protoliths. Petrographic investigations showed that the metabasites contain assemblage actinolite + zoisite + plagioclase + chlorite + epidote + quartz ± titanite in the lowest metamorphic grade (green schist facies) that was replaced by hornblende + plagioclase + garnet + clinopyroxene + quartz ± titanite assemblage at the peak of the metamorphism (lower granulite facies). Based on the thermodynamic phase diagrams (pseudosection) calculated for these rocks, the metamorphism at the green schist facies occurred at T < 550 C° and P < 5 kbar, while the peak condition occurred T and P 640 to 750 C° and 6.5 - 10 kbar, respectively. The other phase diagrams indicate that the low MgO content in the protolith and CO2</sub> content in the metamorphic fluid played an important role in the formation and stability of the metamorphic assemblages observed in the metabasites of the Qori metamorphic complex.