جستجوی مقالات مرتبط با کلیدواژه « ایران مرکزی » در نشریات گروه « علوم پایه »

In the western boundary region of Central Iran with Sanandaj-Sirjan, considering the widespread carbonate units in the northeastern Isfahan area, the barite deposits have considerable potential. The Komsheche barite, hosted in the Middle Triassic Shotori dolomite Formation, is the most active mine in the region. Barite mineralization has occurred in two styles, banded-layered and veined-brecciated. Fluid inclusions in the bedded barite homogenize at temperatures from 78 to 122 ºC, with salinity between 10.9 to 17.0 wt.% eq. NaCl, while the homogenization temperature for two-phase inclusions of the second type barite is between 130 to 187 ºC and associated halite-bearing tri-phase inclusions range from 192 to 210 ºC, with an average salinity of 14.3 and 36.6 wt.% eq. NaCl, respectively. The δ34S values of the samples range from 18.40 to 26.34 per mil CDT, and their δ18O values range from 8.9 to 14.7 per mil SMOW. Based on conducted studies, ore-forming fluids were formed in an open and near-bottom seawater system during the early diagenetic stage. The heavy isotope values related to pore water are locked in a closed system during the final stages of diagenetic. Sedimentary type, associated minerals, REE composition, finding of fluid inclusion and isotope reveal that Komsheche barite has the most similarity to diagenetic/cold-seep types of marine barites.

In order to study the biostratigraphy and palaeoecology, the Qom Formation has been studied in the Ghamsar section of Kashan. The studied section, with a thickness of 314 m, consists of medium to thick-bedded to massive limestones and shale. The Qom Formation overlies the Eocene volcanic rocks in the Ghamsar section and is covered by the Recent alluvial sediments. A total of 21 genera and 9 species of benthic foraminifera were identified in this section and the results indicated the age of Rupelian-Chattian. According to the above palaeoecological conditions, in the lower parts of this section (Rupelian), light conditions are euphotic and nutrient conditions are first eutrophic and then Meso-oligotrophic with mainly normal sea salinity. During Chattian, the trophic state was mainly meso-oligotrophic with normal salinity, and salinity varied between 40 and 50 PSU. Light conditions also were between aphotic and mainly meso-oligophotic. Large benthic foraminifera with hyaline walls, such as Amphistegina, Lepidocyclinide and Nummulitide, in shallow environments with high energy, have thicker shells and smaller shell size, and in deep environments, due to reduced light intensity and low water circulation, they have thinner and more elongated shells. The results of the morphometry of 186 samples of Amphistegina show that the seawater depth in Ghamsar section (Rupelian-Chattian) fluctuated from less than 11 meters to less than 44 meters.

Hashemabad deposit is located in southeastern part of Esfahan province (Naein), in Central-Iran Zone and within Cretaceous-volcanic rocks. This system is a part of Naein-Ardestan basin which consists of Cretaceous sub-seafloor lava, volcano-sedimentary rocks, and ultrabasic-rocks which formed in extensional environment. This complex located in a tectonic zone (strike-slip fault) adjacent to Urumieh-Dokhtar magmatic arc. Main altered and metamorphosed rocks in this area include Middle-Upper Cretaceous basaltic-lava, andesite, basaltic-andesite, rhyolite and rhyolitic-tuff and younger subvolcanic masses which emplaced in relation to strike-slip faults. Andesite and basaltic andesite which well distributed in whole area are the main host of copper mineralization. Propylitic, argillic, sericitization, silicification, carbonatization and sulfidation are main alterations which well distributed along fault and fractures. However, the intensity of silicification and carbonatization increases in proximity of the mineralized zone. Ore mineralization generally is concomitant with bedding of host basaltic andesite lava in form of disseminated and lens shape and has observed with stratabound geometry along local and cross-cutting faults. Ore minerals have vein-veinlet, open space-filling, disseminated and replacement textures. Ore minerals include chalcocite, bornite, chalcopyrite and pyrite along with secondary minerals such as covellite, chalcocite, malachite, hematite, goethite and azurite. Geochemical studies proposed high potential and enrichment of copper (less Ag&Mo) in this area. The presence of relatively good amounts of gold in tuff units containing jasper as well as in the place of argillic-alteration is one of the unique features of this area. Considering the above evidences, this deposit could be considered as Manto type copper deposit.

The country of Iran is part of the Alpine-Himalayan orogeny belt and is divided into different tectonic seismic states. Based on the classification of tectonic seismic states, Kerman province is located in the central Iran zone. The city of Hojedk is also located in the seismic state of central Iran, which is in a relatively high-risk zone in terms of seismicity and has experienced large earthquake events. In this research, for the first time, the city of Hojedk has been comprehensively investigated in terms of seismic conditions to facilitate the decision-making process for preventive measures, especially the improvement and strengthening of buildings against earthquakes. In this research, data from the catalog of earthquakes of the University of Tehran's Geophysics Institute were used to analyze the earthquake hazard, and geological maps of the Geological Organization were used in the geological surveys and faults in the area.Earthquake hazard analysis in Hojedk City has been done in a probabilistic way. In this method, seismic springs have been identified and determined for the area. The information on the faults in the region and the earthquake catalog have been used for this research stage. At this stage, seismic springs are considered regionally. After determining the seismic springs, the seismic parameters were calculated and then the strong ground motion was estimated and finally, the earthquake hazard analysis was done by combining the uncertainties in the earthquake position and the magnitude of the strong ground motion parameters in the specific time period.The city of Hojedk is placed in a very high seismic risk zone. Major earthquakes have occurred in the area of this city. Due to geology, this city is located on the Shemshak, Badamo, Hojedk and Shotori formations. There are many faults in the city of Hojedk, the closest fault to this city is the Deh Zana fault. The length of this fault is 18 km and its mechanism is thrust. The area of Hojedk City is an active area in terms of the occurrence of earthquakes. In this area, 6 historical earthquakes have occurred, the largest of which occurred with a magnitude of 6.1 in 1897. Historical earthquakes are in the large range and the smallest of them has a magnitude of 5.5. 4141 earthquakes occurred in the range from 1900 to 2023, of which 4 earthquakes occurred in this time range with a magnitude of 6 or more. 8 seismic springs of regional type were identified based on the trend of faulting and accumulation of earthquakes in Hojedk city. Research on aftershocks has shown that the number of events with a magnitude of about 3.4 to 5 is the highest, and the depth of most earthquake events is between 10 and 20 kilometers.The seismic coefficients a, and b calculated in this range are 0.86 and 3.88, respectively. The seismicity rate in the studied area for magnitude 4 and greater is 1.47. The hazard analysis of the area for the return period of 475 years shows that the maximum acceleration of the bedrock in the area is 0.45, which is in the area of Hojedk city is 0.25-0.35. The acceleration map shows that the highest accelerations are in the northwest-southeast trend, which is in good agreement with the trend of the faults. Therefore, in terms of construction laws, the studied area is of special importance, so by having soil boreholes in the area, seismic micro zoning can be done and its results can be used to improve construction and select and use materials.

Saghand Anomaly 2 is located in 180 km NE of Yazd, 40 km east of Saghand village and east of Tashk mountain. This area is part of the Bafgh-Saghand metallogenic zone in the Central Iran Zone. The early Cambrian volcano-sedimentary unit consisting of intermediate- acidic volcanics, dolomitic limestone and small amounts of gypsum layers hosts iron-uranium mineralization in Sagand region. Uraninite is the main host of uranium associated with magnetite and pyrite. Molybdenite is rarely present in some parts f mineralization zones. Fe and U mineralizations occurr in two separate stages. coarse-grained Magnetite and pyrite are related to the Fe-mineralization stage while their fine-grained types form in the U-mineralization stage. The U content varies between 1365 and 4764 ppm in the analysed samples. As well as, Ce, Fe, Hf, Nb, S, Sc, Ta, W, Yb and Zr show enrichment, and Fe and S have the largest ranges of changes. The major and rare earth elements can be divided into two groups according to their association with U. The first group includes S, Fe, Ce, Dy, Er and Gd that show positive correlation with U and form in the same condition. The second group including Ti, Hf and Nb, have negative correlation with U and probabely form in the different condition. The rare-earth elements diagram show depletion in Eu and Pr and enrichment in Ce and Sm. The chemical composition of uraninite and the similarity of the distribution pattern of rare earth elements in uraninite of Saghand Anomaly 2 with metasomatic deposits show that the uranium mineralization in Saghand Anomaly 2 is metasomatic type and based on the chemical composition and distribution pattern of rare earth elements in the uraninite its formation temperature is between 200 and 350 ̊C.

Uranium is the main raw material for the production of nuclear energy. The development of nuclear energy significantly increases the extraction of uranium, therefore it is very important to pay attention to this metal and the environmental effects of its mining in our country.Iran's uranium deposits are mostly located in central Iran. Several deposits have been identified in this zone, one of which is the anomaly located 170 kilometers northeast of Yazd city. Chah Juleh area is located in the northeast of Yazd city and in the east of the 1:100,000 map of Ariz. It is bounded from the north by the Saghand desert, from the west by the Khashumi mountains, from the east by the Chadormello iron ore mine, and from the south by the Zarigan region (Figure 1).
The general morphology of the area is rocky and rough. This area was identified for the first time by aerial flights, during which two anomalies were identified in the north and south of the area. The anomaly in the south of the region was not followed due to the lack of surface outcrop.The development of nuclear energy will reach its peak in the next few decades. Since uranium is the main raw material of nuclear energy, the environmental problems caused by mining must be taken seriously by government agencies.

In order to carry out lithology, mineralogy and geochemical studies, about 125 rock samples (35 samples for preparing thin sections, 23 polished sections, 10 samples for X-ray diffraction analysis and about 60 samples for X-ray fluorescence analysis from the Different areas of the region, especially the mineralized points, were collected and studied .Among the alterations in the region, we can mention hematitization, chloritization, epidoteization, silicification, carbonateization, and kaolinization.Zarigan leucogranite in the studied area has been affected by Sodic metasomatism in some parts and has turned into albitite, these parts, which are seen in red color (Figure 2-b, p), have radioactivity and sometimes with a scintillometer device show the radiation intensity of 2500 cps and their radiation is related to the opaque minerals in them. These opaque minerals form a dark red halo around the opaque mineral as a result of the radioactive decay, which can be seen in the hand sample and is one of the evidences of the radioactivity of these minerals (Figure 2-P). Of course, white albitites can also be seen in the region, which do not show any special radioactivity.According to petrographic studies, Zarigan leucogranite has a porphyry to granular texture, and the samples that have been affected by metasomatism have a coarse-grained granular texture. Its main minerals include: quartz, alkaline feldspar andplagioclase. Alkaline feldspar in Zarigan leucogranite includes perthite and microcline. In the samplesaffected by metasomatism, albite mineral was formed as a result of substitution instead of alkaline feldspar and calcic plagioclase. Albit with a checkerboard pattern is one of the specialties of Sodic's metasomatism.According to mineralogical studies, the opaque minerals of albitites include titanomagnetite-dividite (Figure 2-e), which are named as U-Ti oxide phases, and their red color is due to the presence of iron oxide in the microfractures of the albite mineral.Among the secondary minerals found in leucogranite and albitites, we can mention zircon, monazite, sphene and rutile, which sphene and rutile are the result of alteration of opaque minerals.At present, the main methods of remediation of decommissioned uranium mines are to ensure the non-proliferation of pollution (Gasem Shirazi, 1401). Physical methods are used to isolate the contaminated area to prevent further damage to the surrounding environment. Conventional physical removal and chemical washing are usually expensive and can easily cause secondary damage to the environment. Phytoremediation is economical and environmentally friendly, but inefficient and limited inenrichment capacity (Gavrilescu et al., 2009). These factors make it difficult to commercialize such methods on a large scale. Uranium contamination is mainly concentrated in underground water. Considering the difficult treatment of groundwater after pollution, it is necessary to strengthen the protection of groundwater during the extraction process (Zheng et al., 2023).According to the results of the analysis of about 60 samples by X-ray fluorescence method, Zarigan leucogranite is a siliceous leucocratic rock (SiO2 W%: 76.944-78.936), peraluminous (A>CNK) and sodic (Figure 3-a) and according to the Rb diagram in Its tectonic environment is related to volcanic arcs (VAG) (Figure 3-b).Environmental solution can be done in three steps. Before extraction, the hydrogeological characteristics and chemical indicators of underground water in the mining area are carefully examined and based on this, the mine construction plan and revitalization goals are established. In the mine drilling design, the direction of underground water flow and arrangement of wells from upstream to downstream should be considered, which can reduce the halo on both sides. During the operation, the extraction volume of the leaching solution should be considered larger than the solvent injection. This can lead to negative pressure in the area and prevent the release of pollutants. After completion, a monitoring system should be set up in the vicinity, especially downstream. A periodic monitoring program should be modified to determine the range of halo emissions (Zheng et al., 2023).

Chah- Juleh area is located in the northeast of Yazd city and in the central Iran zone. The local geological setting consists up Zarigan leucogranite, quartz diorite and diabasic dykes. The Zarigan leucogranite has pervasively influenced by Na- metasomatism and has converted to albitite. These albitites are main hosted of U mineralization. U mineralization consists of U- Ti Oxide phases (Dividite- Titanomagnetite). According to geochemical studies, albitites are enriched in alcalies, Al2O3, U, Th, Nb, and REE. Also spider diagrams are shown enrichment in Ba, Th, U, Zr, Sr, Nb, Ce and depletion in zn, Cr, Ni, Rb, Pb, This enrichment reflect communion of continental crust in genesis of productive magma. Acording to field observations, petrography and geochemistry studies U- mineralization is supposed to be associated with late magmatic albitites. Uranium extraction, especially in dry weather conditions and poor drainage, can have environmental consequences, and environmental measures must be taken to prevent pollution.

The present study investigates lithofacies and petrofacies in details and also reconstructs the depositional environment of the Paleocene siliciclastics of the Kerman Formation located in NE Central Iran, which is composed significantly of polymictic conglomerate bodies intercalated with some minor sandstone beds. Through detailed sedimentological studies (e.g., dominant grain size, degree of clast rounding and sorting, texture, and stratification), five lithofacies have been identified: clast-supported massive conglomerate (Gcm), matrix-supported massive conglomerate (Gmm), horizontally stratified conglomerate (Gh), horizontally bedded sandstone (Sh), and massive sandstone (Sm). Petrographic analysis revealed three petrofacies composed of petromict conglomerate, volcanic arenite, and feldspathic litharenite; gravels chiefly made up of basalt and andesite, as well as fewer limestone and agglomerated tuff. The lithofacies associations are related to sedimentary gravity flow (SG) and channel-fill sandstone bodies (CH) deposited in alluvial fan and braided fluvial systems. This research provides important insights into the sedimentary environments of the Kerman Formation.

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

The Lower Oligocene basic dikes are cropped out in the Chah-e-Alikhan area (Northeast of Isfahan province, North of the Daq-e-Sorkh desert). These dikes show NE-SW and NW-SE trends and cross cut the Eocene volcanic rocks and associated flysches. NW-SE dikes are younger and cut the NE-SW ones. These dikes are similar in petrography and are composed of plagioclase, clinopyroxene, olivine, sanidine, Cr-spinel and ilmenite. Zeolite, serpentine, calcite and magnetite are secondary minerals. These dikes represent the porphyritic, glomeroporphyritic, poikilitic and trachytic textures. Intergranular and granular textures can be seen at the center of the larger dikes. These basalts are enriched in alkalis (Na2O+K2O), LREE and LILE (Cs, Rb, Ba, Pb) and have high values of LREE/HREE ratio (La/Yb=8.9-10). In the classification diagrams, which are based on the incompatible elements and HFSEs, they are classified as alkali basalts. The primitive magma of these basaltic dikes has been produced by partial melting of a garnet-spinel lherzolite of the mantle previously suffered the carbonate metasomatism. The formation of the alkali basalt dikes of the Chah-e-Alikhan area can be ascribed to the former subduction of the Central- East Iranian Microcontinent (CEIM) confining oceanic crust and decompression melting induced by the extensional basin of the Anarak‒Jandaq area in Early Oligocene. The primary basaltic magma has been formed by low degree of partial melting of a metasomatised mantle lherzolite during continental crust extension episode in the lower Oligocene and has been ascent through the faults. 

In the Northwest of CEIM (Central-East Iranian Microcontinent), along the Great Kavir fault, volumes of alkali basalts with the lower Oligocene age are outcropped as volcanic and subvolcanic (Dike) rocks. In this research, the subvolcanic exposures of this basic magmatism in the the Chah-e-Alikhan area is discussed. The Lower Oligocene basic dikes are cropped out in the Chah-e-Alikhan area (Northeast of Isfahan, Northeast of Zavareh, and Northwest of the CEIM). These dikes show NE-SW and NW-SE trends and cross cut the Eocene volcanic rocks and associated flysches. In this paper, the geological and petrological aspects, as well as the geodynamic setting of alkali basalt dikes of the Chah-e-Alikhan area are discussed. Study of these dikes, as a part of the Cenozoic alkaline magmatism from Northwest of the CEIM, will be useful in understanding the geodynamical evolution of the Central Iran.

 The method of study is including petrography (field, library and microscopic studies) and whole rocks geochemical analysis of rocks. 13 fresh whole rock samples of alkali basalts from the Chah-e-Alikhan area were selected for the major and trace elements chemical analyses.
Whole rock geochemical analyses carried out by using a Bruker S4 Pioneer XRF at the Central Laboratory of the University of Isfahan. Trace element compositions of the selected samples were achieved by ICP-MS (Inductively coupled plasma-mass spectrometry) at the Zarazma Mineral Studies Company (Tehran, Iran). 

The rock-forming minerals of the Chahe-e-Alikhan basic dikes are Cr-spinel, olivine, clinopyroxene, plagioclase, sanidine and ilmenite. Zeolite, serpentine, calcite and magnetite are secondary minerals which are formed as a result of the alteration of primary minerals. Petrographical characteristics indicate that these dikes are alkali basalt and represent the porphyritic, glomeroporphyritic and trachytic textures. Intergranular and granular textures can be seen at the center of the larger dikes.
These basalts are enriched in alkalis (Na2O+K2O=4.5-5.4 wt%), LILEs (Cs, Rb, Ba, Pb) and have high values of LREE/HREE ratio (La/Yb=8.9-10). Trace elements ratio diagrams such as La/Nb versus La/Yb, Dy/Yb against La/Yb, Sm/Yb versus La/Yb (Bogaard and Worner, 2003) and Ce/Yb-Ce (Ellam, 1992) are used in order to determination of the depth, type and degree of partial melting of the source rock. Based on the geochemical characteristics and diagrams, the primitive magma of the Chah-e-Alikhan alkali basalts possibly have been produced by about 5 to 10 percent partial melting of a garnet-spinel lherzolite, which is located at the depth of about 105 km, as a part of a mixed asthenospheric–lithospheric mantle. The elevated values of the Zr/Hf ratio and the Na2O + K2O versus TiO2 diagram (Zeng et al., 2010) indicate that the primitive magma of the studied basic dikes previously suffered the carbonate metasomatism.
The Chah-e-Alikhan alkali basalts show high values of the Alkalis (Na2O + K2O), enrichment in LREE, HFSE and LILE. The subducted oceanic slab is the source of carbon and LILEs are the mobile components of subduction (Shaw et al., 2003). Considering that Cs is a highly fluid mobile element, enrichment in Cs relative to Rb suggests that the fluid phases derived from a subducting slab are probably the metasomatic agents.
The lower Oligocene alkaline magmatism in the Chah-e-Alikhan area and the enrichment of the mantle with incompatible elements (metasomatism) can be attributed to two oceanic crust subduction events: (1) Northeast ward Neotethys subduction along the Zagros Thrust Zone beneath the Central Iran from the Triassic to the Eocene (Torabi, 2010); and (2) Subduction of an oceanic crust along the Great Kavir Fault, which is situated to the western margin of the CEIM. The spreading of the last ocean crust started in the Triassic and ended in the Eocene. The remnants of this oceanic crust are found as ophiolitic melanges on the western side of the CEIM, such as the Nain, Surk, and Ashin ophiolites (Rajabi and Torabi, 2012; Torabi, 2010). The geological history and position of the Chah-e-Alikhan alkali basalt dikes suggests that the the carbonate metasomatism of the mantle peridotites can be attributed to the subduction of the CEIM confining oceanic crust.
Several tectonic discrimination diagrams have been used for determination of the tectonic setting of the Chah-e-Alikhan basalts. The La/Yb versus Th/Nb (Hollocher et al., 2012), Ta/Yb against Th/Yb (Gorton and Schandl, 2000) and DF1 versus DF2 (Verma and Agrawual, 2011) diagrams suggest a within-plate (continental) tectonic setting.
The activity of the major faults of the area such as Great Kavir, Chah Mishury and Chah Gireh Faults has been created a suitable inter-plate extensional system to ascending the Lower Oligocene alkali basalt magma in the Chah-e-Alikhan area.

The Lower Oligocene alkali basalts of the Chah-e-Alikhan area is a part of the intra-continental alkaline magmatism crosscuts the Eocene volcanic rocks. The area provides a setting to study the Cenozoic alkaline magmatism of the northwest of the CEIM.
These basalts are enriched in total Alkalis, TiO2, LREE and LILEs. They have been produced by about 5 to 10 percent degree of partial melting of a garnet-spinel bearing lherzolite of a mixed lithospheric-asthenospheric mantle which is previously metasomatised. The mantle enrichment can be ascribed to the subduction of the CEIM confining oceanic crust beneath the Central Iran from the Triassic to the Eocene. The Grate Kavir Fault and related faults have played an important role in the Lower Oligocene alkaline magmatism in northwest of the CEIM.

The authors thank the University of Isfahan for financial support.

In central part of the Mesozoic Ashin ophiolite (Northwest of Anarak, Isfahan province, Iran), the Upper Eocene monzonitic stock cross cuts the Ashin ophiolite and Middle Eocene volcanic rocks. Amphibolite xenoliths are enclosed in the stock and associated Eocene volcanic rocks. Xenoliths are more abundant in the margin of the monzonitic stock. Rock-forming minerals of the stock are plagioclase with andesine to labradorite composition (An=34-60%), Alkali-feldspar with orthoclase composition (Or= 70.8 to 96.1%), diopsidic clinopyroxene with (Mg# =0.71-0.90), and phlogopite mica with (Fe#=0.3). Opaque minerals are magnetite and titanomagnetite (TiO2=1.6-4.4 wt.%). Main textures of samples from this intrusive body are granular, intergranular and poikilitic. Samples from the margin of this stock represent porphyritic texture. 
Geochemistry of minerals and whole rock samples of this stock indicate that they belong to the calc-alkaline magmatic series and are similar to the samples from the continental magmatic arcs.
These magmatic rocks possibly were formed by subduction of the CEIM (Central-East Iranian Microcontinent) confining oceanic crusts (Ashin and Nain oceanic crusts) during Mesozoic and Early Cenozoic eras.

Iran is a part of the Alpine-Himalayan orogenic system, including the Paleozoic to Cenozoic ophiolites, magmatic and metamorphic rocks (Takin, 1972; Berberian and King, 1981; Berberian et al., 1982; Dercourt et al., 1986; Alavi, 1994; Mohajjel et al., 2003; Shahabpour, 2007). The main pulse of the Paleogene and Neogene magmatic (volcanic and intrusive) activities of Iran can be attributed to the two Cenozoic subduction events, including the western Neo-Tethyan oceanic crust subduction beneath the Sanandaj-Sirjan block in the west and the eastern Neo-Tethyan oceanic crust subduction beneath the Central Iran (e.g., Shirdashtzadeh et al., 2022). The former subduction possibly caused to the formation of the Urumieh-Dokhtar Magmatic Arc, but the later subdution results is not well studied yet. 
In the this research, the target region is located in the west of the Yazd block (Central Iran), where the Eocene volcanic and plutonic rocks represent subduction-related characteristics (Jamshidzaei et al., 2021). The investigated subduction-related monzonitic stock that cross cuts the central part of the Ashin ophiolite in the Kuh-e-Kalut-e-Ghandehari region, in the northwest of Anarak (Isfahan Province, Iran). The main lithologies in the Kuh-e-Kalut-e-Ghandehari are Mesozoic lithologies of Ashin Ophiolite, Paleocene limestone, Eocene volcanic rocks, monzonitic stock, Lower Red Formation, and Akhoreh Formation. Ashin ophiolite was formed in the mesozoic (Shirdashtzadeh et al., 2022) and emplaced in the Late Paleocene (~60 Ma; Pirnia et al., 2020; Shirdashtzadeh et al., 2022), before than Eocene volcanism and plutonism. The studied monzonitic stock of the Kuh-e-Kalut-e-Ghandehari intrudes the Mesozoic Ashin ophiolite and Middle Eocene volcanic rocks.
The calc-alkaline affinity of the volcanic and plutonic rocks of the area, tectonic activity of the Great Kavir fault caused to the crushing and mylonitization of the surrounding rock units, as well as the alteration evidences in the field studies point to suitable conditions for the ore deposit exploration in the area (e.g., copper). In this research, the petrology, mineralogy, and whole rock geochemistry of the Upper Eocene monzonitic stock are considered. This research will expand our understanding of the geochemical nature of subduction-related Cenozoic magmatism in Central Iran.

After detailed field studies and sampling, the selected fresh samples were used for microscopic thin section and polished-thin section studies by the polarizing binocular microscope (Olympus BH-2). The microprobe analyses were performed at the School of Natural Systems, College of Science and Engineering, Kanazawa University (Kanazawa, Japan) using a wavelength dispersive electron probe microanalyzer (EPMA) (JEOL JXA-8800R). The mineral analysis was achieved under an accelerating voltage of 20 kV, a probe current of 20 nA, and a focused beam diameter of 3μm. 14 whole rock samples analyses were performed by Brucker S4 PIONEER XRF in the central laboratory of the University of Isfahan and 3 samples were analyzed in the Isfahan Nuclear Technology Center by neutron activation analysis (NAA).

Based on the field relation ships, this gray to light gray pluton intrudes into the Middle Eocene volcanic rocks and belongs to the Upper Eocene. The Middle Eocene volcanic rocks and Upper Eocene monzonitic stock crosscut the Ashin Ophiolite. This Eocene stock and volcanic rocks contain amphibolite xenoliths with the same mineralogy and petrography. Xenoliths are more abundant in the margin of the monzonitic stock. Gradual decreasing of modal plagioclase content indicates that the xenoliths range from amphibolite (plagioclase + amphibole) to hornblendite (only amphibole) in composition.
Rock-forming minerals of the stock are plagioclase with andesine to labradorite composition (An = 34-60 %), alkali-feldspar with orthoclase composition (Or = 70.8 to 96.1%), diopside clinopyroxene with Mg# = 0.71-0.90, and phlogopite mica with Fe# = 0.3. Opaque minerals are magnetite and titanomagnetite with TiO2 = 1.6-4.4 wt%. The main textures of samples from this intrusive body are granular, intergranular and poikilitic. Samples from the margin of this stock represent porphyritic texture. The SiO2 value in the whole rock compositions ranges from 47.9 to 61.65 wt.% (basic to intermediate). The average content of alkalis is 9.75 wt.%). The Kuh-e-Kalut-e-Ghandehari rocks show sodic affinity by higher Na2O than K2O, based on the Na2O/K2O versus SiO2 and K2O/Na2O versus SiO2 diagrams (Jaques et al., 1985). The Eocene intrusive and volcanic rocks of this area are similar in terms of mineralogy and texture. Petrography and whole rocks chemical analyses indicate that the studied stock is geochemically composed of gabbro, monzodiorite to monzonite in composition with metaluminous affinity. Monzonite is the predominant rock.

Various tectonomagmatic discrimination diagrams are used to determine the tectonomagmatic setting of the Kuh-e-Kalut-e-Ghandehari stock. Mineral chemistry and whole rock geochemistry of the Kuh-e-Kalut-e-Ghandehari monzonitic stock indicate a calc-alkaline magmatic series similar to the subduction-related magmas in the normal continental magmatic arcs formed during the mantle metasomatism. According to the the temporal and geological situation, as well as the geochemical characteristics of the Kuh-e-Kalut-e-Ghandehari stock, it is considered as a part of an arc magmatism, related to the subduction of Neo-Tethyan oceanic crust beneath the CEIM (Central–East Iranian Microcontinent) during the Late Mesozoic and Early Cenozoic eras.

We are grateful to the University of Isfahan and the Department of Geology of Kanazawa University (Japan) for their supports. We are also grateful to anonymous reviewers for their useful comments and suggestions that improved the quality of this paper.

The Anar fault in the east of Yazd city, with a north-northwest-south-southeast strike, is a basement fault that separates the Yazd block from the Posht Badam block, and its current activity is a dextral strike-slip with a reverse component. The paleostress analysis was done on this fault in order to obtain the tectonic history of central Iran in the period from Devonian to Cretaceous. After analyzing 110 fault data in 13 stations of 2 tectonic phases, it was determined that the maximum stress obtained is between the azimuths of 90 to 110 and 190 to 220 and the angle of stress direction changes in the period from Devonian to Cretaceous is 130 degrees. Based on the studies on the barite veins and the dextral displacements that were seen on them, the separation of the stress phases was done, which indicates that the NNE stress direction is older. Further, according to the previous studies of sedimentology and tectonics in central Iran, it was concluded that the cause of this change in tension was the movement towards the northeast along with the 130 degree counter-clockwise rotation of central Iran.

Band-e-Cherk prospect is located in the north of Isfahan province, on the western boundary of the Central Iran zone. The rock outcrops in this area are mainly comprised of Anarak Palaeozoic-Mesozoic metamorphic complex, Lower Cretaceous sedimentary sequence, Paleocene conglomerate, and Eocene volcanic rocks. The host sequence involves two units, from bottom to top: 1) Palaeozoic-Mesozoic metamorphic complex, and 2) Lower Cretaceous succession. Mineralization is occurred as vein/veinlet, replacement, banded, breccia, banded, spotted, and microbial remains (botryoidal, radial, and needle). The main ore minerals are hematite, goethite, pyrolusite, braunite, psilomelane, and minor todorokite, cryptomelan, and manganite associated with pyrite, galena, and chalcopyrite. Gangue minerals mostly are dolomite, quartz, calcite, barite, and amorphous silica. Magnetic survey reveals a high-positive magnetic anomaly (up to 2900 nT) which coincides with the location of a magnetite-enriched metagabbroic body, east of the study area. Interpretation of the magnetometry results using geological evidence points to an asymmetric anticline, and occurrences of hematiteare found on its limbs. the ore samples have higher Ba, Pb, Si, and Sr contents, and lower Co, Ni, P, and Ti concentrations .Our results indicated that the mineralization form during the three metamorphic, hydrothermal, and supergene processes, respectively. Based on mineralogy, textures, and chemical variations, Band-e-Cherk mineralization is similar to those typical of hydrothermal deposits where the circulation of fluids into the fractured Anarak metamorphic complex has provided the conditions for the formation of iron and manganese mineralization.

The study area is part of the Troud geological quadrilateral, which is located in the central Iran zone from the perspective of structural geology of Iran. The two main faults of Troud in the south and Anjilo in the north, with their vertical movements and the extension of their left slip, play an important role in structural events and the movement of mineral fluids and mineral deposits. The study area is composed mostly of volcanic rocks and less volcanic-sedimentary rocks with a combination of intermediate to basic and Upper Middle Eocene.
Gazkhizan region has a mineralization zone 350 meters long and 50-70 meters wide with an almost "east-west" trend. The fracture geometry in this region was determined using Win Tensor and Georeient software.
There is also a northeast-southwest shear zone with copper veins. Fracture analysis in this area shows that most vein fractures are consistent with T-type fractures due to the function of a left lateral shear area. These vein fractures are located north, northeast-south, southwest.

The investigated area is located in the south of Qom. In this study, quantitative morphometric and qualitative components of structural geology have been investigated in the evaluation of the active tectonics of the region. Among the quantitative indicators used in this research, we can mention the hydrometric integral, basin asymmetry, reverse topographic symmetry, dip-length of the river, sinuosity of the mountain front, longitudinal profile of the river, dip of the basin and shape of the basin, and for the components Qualitative, geometrical analysis of Bidhand fault system has been used. In this research, the drainage basin area of the region was divided into 4 sub-basins based on the separation of sub-basins based on 1:50,000 topographic maps, Landsat 30 and 15 meters satellite images, IRS (5.5m), SRTM (90m) and geological maps of Qom and kahak is on a scale of 1:100,000. the level of relative tectonic activity (Iat) of the studied area was divided into three categories of relative tectonic activity. With the qualitative assessment of lithology and geological structures affected by the Bidhand fault in each basin, it was determined that there is a significant relationship between the results of geometrical investigations of structural elements as qualitative components and morphometric measurements as quantitative components, which is due to This alignment of the level of relative tectonic activity of the region in the sub-basins of Kermejegan, Fordo and Kahak was evaluated as very active and in the sub-basin of Sarm were also evaluated as active.

In order to study  the Lower Cretaceous deposits' coral fossils, the Baghin section was chosen and sampled. This section consists of a sequence of green marl, limestone and shaly limestone deposits. In this section, diverse groups of microfossils (orbitolinids, algae and ostracods) and macrofossils (corals, echinoids, bivalves, brachiopods, gastropods,…) are present. The presence of diverse collection fossils, especially large orbitolinid foraminifera indicated a favorable environmental conditions and absence of planktonic foraminifera indicated shallow environmental conditions. Also, the presence of platycopid and podocopid ostracods and corals confirm the shallow, warm, light and suitable paleoecological conditions.

The Kuh-e-Kalut-e-Ghandehari is located about 40 Km northwest of the Anarak (northeast of Isfahan). This area is a part of the Central Iran that is situated in west of the Yazd block; near to the Ashin ophiolite and drastic directional changes of the Great Kavir Fault. In the northwest of Anarak, the Ashin ophiolite is covered by the Cretaceous limestones, and crossed by the Eocene volcanic rocks. The Upper Eocene gabbro-diorite stock cross cuts the Eocene volcanic rocks. Andesites are the predominant unit of the Eocene volcanic rocks. They are grey to dark- grey in colour and have amphibolite xenolith. The main textures of these volcanic rocks are porphyritic, poikilitic, trachytic, sieved texture and glomeroporphyritic. The main phenocrystic minerals of andesites are plagioclase, amphibole and clinopyroxene situated in a matrix of the same minerals and sanidine, magnetite and apatite. Secondary minerals are formed as a result of the hydrothermal alteration and comprise zeolite, chlorite, epidot, sericite, kaolinite and calcite. Mineral chemistry indicates that plagioclases are andesine to labradorite (An= 30-52%), K-feldspars are sanidine (Or= 68-71%), amphiboles are calcic with pargasite composition (Mg#= 0.58-0.71), and clinopyroxenes are diopside (Mg#= 0.91-0.93) in composition. Whole rocks chemical analyses indicate that these andesite and trachy-andesite rocks have calc-alkaline property. The chondrite and primitive mantle-normalized REE and multi-element patterns show LREE and LILE enrichment and HFSE (Ti, Ta, Nb) depletion, which are characteristics of the subduction-related magmas. These data indicate that the primary magmas were genarated by medium degrees of partial melting of the lithospheric mantle spinel lherzolite. Subduction of the Central-East-Iranian Microcontinent (CEIM)-confining oceanic crusts (Naein and Ashin oceanic crusts) are possibly the reason of this volcanism. Geochemistry of these volcanic rocks are similar to the arc-related ones.

The northwest zone of Saveh city is located in the Indes, Kooshk e Nosrat, Avaj, and Aipak fault zones. Indes, Kooshk e Nosrat, Avaj, and Aipak faults are considered the major faults in central Iran, which are also active in the Quaternary, and their last movements are attributed to the present time. Therefore, the estimation of morphometry to identify the effect of active tectonics on the tectonic evolution of drainage basins seems necessary. In this study, six important morphotectonic indices were analyzed including the longitudinal gradient of the river, asymmetry of the drainage basin, hypsometric integral, drainage basin shape, the ratio of the floor width to the valley height, and mountain front. To model the formation of basins in the studied area, Arc Hydro software (Arc GIS add-ins) was used based on data derived from a digital elevation model. Then, 6 morphotectonic indices were compiled and classified on each of the basins. Finally, the Active Tectonic Index (IAT) was calculated, according to which the study area was classified into 4 categories including very high, high, intermediate, and low tectonic activity. According to the IAT index, 5% of the study area shows very high tectonic activity, 25% of the studied area has high tectonic activity, 65% of it has average tectonic activity and about 5% of the tectonic activity is low. Moreover, seismic acceleration was prepared to confirm the result of morphological indices in the estimation and analysis of active tectonics in the region. In this study, the highest level of tectonic activity can be seen in the north-eastern part of the area. In most sectors, the level of activity is high and intermediate, which is related to the activity of Kooshk-e-Nosrat, Aipak, and Avaj faults.

The Lachinag synformal anticline is located to the northwest of the Mil anticline and the western end of the Dochah Fault in northern central Iran. This synform includes the terminal members of the Qom Formation (members E and G) and the Upper Red and Pliocene conglomerates. Additionally, with an axial surface plunge from the northwest to the southeast, this fold trends toward the southeast, resulting in its asymmetric geometry. In this synform, the deformable marl and gypsum layers of the E and G members of the Qom Formation have contact with the competent conglomerate and sandstone layers from the Upper Red Formation. The juxtaposition of these layers and the occurrence of deformation phases resulted in the migration of ductile layers as well as a significant increase in the thickness of the marl and gypsum deposits of the Qom Formation (particularly in the E member). Due to the migration of these layers towards low pressure areas and their substantial thickening at the hinge of the Lachinag synformal anticline, the layers as well as the limbs of this fold were overturned. Finally, a synformal box fold was formed. Structural investigations have revealed that this fold initially formed as a result of the right-lateral strike-slip shear parallel to the Dochah Fault. This process occurred during the post-Miocene under the influence of counterclockwise left-lateral strike-slip shear forces around a pole axis at approximately 135 degrees from the north. Consequently, the fold acquired a synformal geometry. The left-lateral shear force may be due to the clockwise rotation of the South Caspian basin and the application of left-lateral shear forces on the northern parts of Central Iran, similar to what has been observed in the Kushk-e Nosrat Fault.

Macroscopic, microscopic and geochemical studies carried out on albite-bearing metasomatites and metasomatic rhyolites hosting the magnetite-apatite deposit of Chogharat indicate the presence of three generations of albite with different concentrations of REE-Y-Ti-Th, in response to T-P reduction and chemical changes of the fluids and the ratio of fluid to rock. The geochemical analysis of the low Ca/Na fluids shows a deficiency in REE-Th mineralization in the white albites, while in the fluids with medium Ca/Na, the REE mineralization (REE>Th) has occurred in the pinkish albites. In contrast, fluids with high Ca/Na indicate Th mineralization (Th>REE) in the red albites. The stable isotopes of C-O on the paragenetic calcites show REE-Y-Ti-Th mineralization of albites due to High-T hydrothermal fluids. Otherwise, the stable O-C isotopes of the Ghoghart apatites and stable isotopes of S in the ore deposits of the BMD verify the role of evaporitic brines and fluid-rock interaction on the mineralization. The presence of calcite and titanite, associated with the calcic-amphiboles and clinopyroxenes, Ca-inclusions in the thorite structure and Ca-content of the thorites, indicate thorite mineralization from the Co32- and Ca2+ fluids due to low activity of the chlorine. According to this study, the source of metasomatism is mainly evaporitic brines with a minor amount of magmatic and related hydrothermal fluids. Mineralization is the result of interaction of the magmatic and hydrothermal fluids of the Late Ediacaran- Early Cambrian plutonic/ subvolcanic intrusions with the evaporitic brines, derived from the synchronous evaporitic sequence.