جستجوی مقالات مرتبط با کلیدواژه « زمین شیمی » در نشریات گروه « زمین شناسی »

The ​​Karat iron deposit is located in the vicinity of Sangan mining district, in the Northeast of Iran. The basement rocks of the Karat area include hornfels, metamorphosed limestone, marble, sandstone, siltstone and red shale with interlayers of marl, shale and marl, thick-layered red conglomerate and alluvial deposits. The intrusion of a granite batholith in the sedimentary units of the Karat iron deposit has led to the formation of iron deposits in the margin of this batholith. The most important ore minerals include magnetite, hematite, goethite, limonite and a small amount of sulfide minerals such as pyrite and chalcopyrite. Geochemical data indicate a strong correlation between the Ni, Mg, and V to Fe in mineralization zone, which indicates the magmatic origin of the Karat iron deposit. In order to investigate the characteristics of the ore-forming fluid of the skarn Karat iron deposit fluid inclusions of quartz veins were analyzed. The results show that fluids are mainly (L+V) type, low to medium salinity (4.48 to 16.42% NaCl) and the homogenization temperature of 200 to 390 degrees Celsius. Mineralogical, geochemical, and fluid-inclusion data show that the magmatics, meteoric and metamorphic fluids are responsible for Fe-mineralization in the skarn and Isothermal mixing and surface fluid dilution are main evolution factors in mineralization fluids. It seems that the main phase of mineralization has been occurred during the retrograde stage skarn.

The Kalateh Bargh prospect area is located NW of Bardaskan, Khorasan Razavi province. Geology of the erea includes sequence of Eocene volcanic rocks with basalt composition and trachyandesite and andesite. On this sequence, there is a conglomerate unit that its fragments are mainly composed of volcanic rocks. The high porosity of the conglomerate as the host rock provided a suitable space for the formation of Manto copper deposits. Mineralization has formed in conglomerate unit as a particular horizon in the Kalate Barq area. Primary minerals include chalcocite and minor bornite and secondary minerals consist of malachite and covellite. Structure and texture of mineralization are veinlet, open-space filling, disseminated and replacement. Mineralogy of alteration zones is related to mineralization and consist of chlorite and calcite. The average copper geochemical anomaly in surface samples is 1.4 %. The presence of chalcocite and absence or low amount of iron sulfide minerals, the presence of chlorite and calcite as the main gangue minerals and lack of quartz indicate that ore solution is reduced and poor of iron and silica. Based on lithology, alteration, mineralogy and geochemistry of Kalateh Bargh prospect area is similar to manto-type copper deposits.

The Tatros kaolin deposit (southwest of Dansfahan, Qazvin Province) is a product of the alteration of rhyodacitic volcanic rocks of the Middle Eocene age. Mineralogical studies show that kaolinite and quartz are the main mineralogical phases and illite, rutile, pyrophyllite, dickite, alunite, and chlorite are accessory mineralogical phases of this deposit. The decrease in the chemical index of alteration (CIA) and the increase in the ratio of (SiO2+Fe2O3+MgO+CaO+Na2O+K2O)/(Al2O3+TiO2) from the center to the outside in the studied profile indicates the existance of alteration and hydrothermal zoning in this  deposit. The distribution pattern of rare earth elements (REE) normalized to chondrite indicates the strong diferentiation and enrichment of light rare earth elements (LREE: La-Eu) related to heavy rare earth elements (HREE: Gd-Lu) and the occurrence of strong negative Eu and Ce anomalies in the studied kaolin samples. Calculations of mass changes assuming Ti as an immobile monitor element show that kaolinitization of rhyodacite rocks is accompanied by enrichment of elements of Al, Sr, Zr, Hf, Ta, Nb, U, Th, Y, La, and Pr, leaching-fixation of Sm, Nd, and HREE, and depletion of Si, Fe, Mg, Mn, Ca, Na, K, P, Rb, Cs, Ba, Pb, V, Cr, Zn, Eu and Ce. The obtained results reveal that the behavior of elements during the development of kaolinitization processes is controlled by factors such as changes in pH and temperature of fluids responsible for alteration, residual concentrations, surface absorption, scavenging by metalic oxides, and the presence of mineralogical phases resistant to alteration. The occurrence of negative Eu anomaly during kaolinitization indicates the destruction of plagioclase by high-temperature hydrothermal fluids. The presence of diaspore, dickite, and pyrophyllite, the enrichment of LREE related to HREE, the differentiation of HREE from each other, and the occurrence of strong negative Ce anomaly in the studied samples clearly suggest the role of hypogene processes in the development and evolution of the Tatros kaolin deposit. Other evidence such as strong positive correlations (La/Yb)N-LOI and P2O5-LOI along with the values of some geochemical parameters such as Ce+La+Y, Nb+Cr, Rb+Sr, and Y/Ho support this idea.

Razgah, Kalibar, and Bozghosh intrusive rocks, located in East Azarbaijan province, are among the most important alkaline nepheline syenite rocks known in Iran. Several theories reported regarding the geochemical characteristics as well as the geotectonic environment of the Tertiary igneous rocks exposed in the Ahar-Arasbaran belt (Jamali et al., 2012). Some workers have considered the magmatism of this belt as an important extensional phase of the late Cretaceous, while, some others believe it is related to subduction zones. Although the mineralogy, petrology, geochemistry, and petrogenesis of these rocks have been studied by several people (i.e., Esmaeili, 1997; Ameri, 2004; Ashrafi, 2009), in none of them the origin and geotectonic setting of the area has been discussed in detail. Thus, for the present study, mineralogical, petrological, and geochemical studies are applied to understand the origin, the petrogenesis, and the geotectonic setting of the intrusive rocks from the nepheline syenite exploration areas, particularly the Razgah intrusive rocks.

 Regional Geology:

The Razgah intrusive. a part of the Western Alborz-Azarbaijan zone lies on the southern edge of the Ahar-Arasbaran volcanic belt. Geologically, the Eocene volcanic rocks cover the Jurassic-Cretaceous flysch is intruded by the Oligo-Miocene plutonic rocks (Mahdavi and Fazli, 2008). The Razgah nepheline syenite intrusive intruded the sediments of evaporate basins including gypsum marl, limestone marl, sandstone, and the Miocene conglomerates. Their contact with previous rocks has vanished due to weathering and erosion of itself and the Quaternary sediments surrounding it. Copper mineralization (malachite and azurite) can be identified in the western part of Razgah intrusive. In addition, a number of dykes are distributed especially in the western and northwestern parts. Also, numerous silica veins were observed in different parts, mainly along, in parallel, and in contact with dykes, more widespread in the western part.

Following the sampling (150 rock pieces) and preparation of 70 thin sections for petrographic and mineralogical investigations, trace and REE were determined on 93 samples using the ICP-MS method.

Petrography:

The Razgah intrusive rocks are dominated by olivine-bearing nepheline gabbro, nepheline monzosyenite, pseudolucite syenite, and K-feldspar nepheline syenite. Also, basic dykes (lamprophyre), similar to their host (altered syenite nepheline), syenite and microsyenite dykes and finally altered dykes with siliceous and mineralized veins are present. Nepheline, pseudolucite, potassium feldspar, plagioclase, clinopyroxene, and olivine are among the most important major minerals. Apatite, zircon, and iron-oxide are the minor while chlorite, calcite, adularia, and hematite along with sericite, epidote, kaolinite, and biotite present as secondary minerals. Granular and porphyroid textures, as well as poikilitics, graphics, and replacements (causing pseudomorphous forms), are the common textures of the rocks under study. Lamprophyre dykes with porphyry texture and olivine, pyroxene, and Kaersutite (brown amphibole) are present. The other dykes, to some extent, have similar mineralogical characteristics as nepheline syenites, in which clay minerals occur.

The Co and Th contents, the amount of Ce/Yb, Ta/Yb, and Th/Yb ratios along with low TiO2 content point to the nature of the parent magma as a high potassium calc-alkaline type (shoshonite). The pattern of REE, LILE, and HFSE, the negative Nb, Ti, and HFSE anomalies as well as Pb and LILE positive anomalies, indicate the mantle metasomatism process or continental crust contamination occurrence (Rollinson, 1993; Soesoo, 2000). In addition, the decrease in P solubility with the high level of K and REE gave rise to the separation of apatite from the parent melt (Green and Adam, 2002). The similarity of REE patterns indicates the same magmatic processes involved in the generation of the rocks under study. The mineralogical and geochemical data on Razgah intrusive rocks and the associated lamprophyres point to 1% partial melting of a spinel lherzolite source. Based on the presented tectonic model, following the Arabian plate subduction beneath the Iranian plate, several processes including the slab breakoff, extensile regime, magma formation from the enriched mantle, and subducted slab melting took place which followed by crystal fractionation and contamination at the base of the crust and finally differentiated melts intruded the high levels. As the gases release, the lamprophyre dykes injected into the fractured roof and the other dykes crosscut the Razgah intrusive rocks.

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.

The geochemical separation pattern and environmental behavior of rare earth elements (ΣREE) have been investigated in 5 different sedimentary systems related to the Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using multi-acid digestion and mBCR (Modified Community Bureau of Reference, European Commission) selective extraction method. The normalization patterns of the total concentration of ΣREE are drawn based on the average North American Shale Composition (NASC) and Upper Continental Crust (UCC). General trends of concentration changes in the five sedimentary systems are very similar to each other, and the concentration of LREEs is higher than that HREEs, just a sample taken from under the rock dump that contains sulfide-leached elements shows a pattern different from other samples and standard patterns. Opposite of the changes in the concentration of ΣREEs, more enrichment is seen in HREEs compared to LREEs. This pattern of enrichment changes is consistent with the higher tendency of HREEs than LREEs for mobility during weathering and oxidation. The geochemical separation patterns of ΣREEs in natural sediment and samples containing iron and manganese oxides are mainly dominated by the residual fraction. Surprisingly, considering the different conditions of formation and stability in the samples taken from the waterways leading to the mine, evaporite deposits and sediments washed from the rock dump, the separation pattern of ΣREEs is controlled mainly with two parts soluble in Acid and reducible fraction. According to the enrichment trends, the trend of mobility and bioavailability from LREEs to HREEs increases with an upward slope. These results show that speciation, geochemical separation pattern and environmental behavior for ΣREEs without considering key environmental factors lead to a lack of understanding or even misinterpretation. The results of this study can be used as a reference in organizing the mine development and environmental planning of the Dar-e-Allo copper mine.

The aim of this research is to investigate the primary mineralogy and the type of diagenesis systems in the south-west of Lorestan based on elemental geochemistry. The Talezang F ormation is formed in this section with a thickness of 84.5 meters and the predominant lithology is limestone and sandy limestone. From this section , 20 samples were selected for EDS and EPMA analysis. The change trend of Sr element to Na compared to Mn showed that the studied samples are in the range of Gordon aragonite limestones of Tasmania . Also, the trend of changes of Mn element against Sr in the studied samples showed that are in the same range as the primary mineralogy of the aragonite of the Mo zdooran Formation, which is a proof of the aragonite mineralogy of the primary limestones of the formation. The high ratio of strontium to manganese (average 63.70) strontium to calcium (average 21.01), low amounts of iron elements (average 1.75 ppm) manganese (average 24.70 ppm), the high concentration of Sr (average of 750.35 ppm) in the studied samples and the plotting of Sr / Ca values ​​against Mn , Mg, Fe indicate a closed to slightly open diagenesis system with exchange of water to rock bottom. (W/R) is for carbonates of Talezang Formation. The relatively open diagenesis system in this formation can be due to the influence of atmospheric fluids due to the presence of an erosional discontinuity that is at the top of the Talez ang Formation.

The Mazraeh manganese deposit (southwest of Maku, north of West-Azarbaidjan Province, NW Iran) is developed in the form of scattered lenses at the contact of pillow basalts and pelagic limestones, belonging to the Khoy-Maku ophiolitic complex. Mineralogically, the ores mainly contain pyrolusite, psilomelane, manganite, and braunite which are accompanied by lesser amounts of hematite, goethite, quartz and calcite. The distribution pattern of REE normalized to chondrite along with some geochemical parameters related to lanthanides, such as La/Ce, (La/Nd)n and (Dy/Nd)n, show a hydrothermal origin for this deposit. This idea is supported by some geochemical diagrams (Co/Zn vs. Co+Ni+Cu, Zn-Ni-Co, and Mn-Fe-[(Co+Ni+Cu)]×10) and elemental ratios such as Mn/Fe, SiO2/Al2O3, U/Th, and Co/Zn. The high concentration of lanthanides in ores (on average of 767 ppm), compared to known hydrothermal manganese deposits, reveals the effects of diagenetic processes on this deposit. The occurrence of negative anomalies of Eu and Ce indicates the low-temperature hydrothermal fluids, responsible for the mineralization. The presence of detrital materials in the ores can be inferred by the concentration values of oxides like Al2O3 and TiO2.

Intrusive rocks are exposed in southwest of Naqdeh in the Sanandaj-Sirjan zone, northwest Iran. There are mafic-intermediate appinitic rocks with calc-alkaline affinity. The accompanying granite is strongly evolved with the affinity of calc-alkaline and rich in potassium. The geochemical analysis of appinite and granitic rocks display LREE enrichment relative to HREE, enrichment of LILE elements, and negative Th and Nb anomalies. According to discrimination diagrams, appinite and granite rocks formed in the continental arc tectonic setting. The appinitic rocks have a lithospheric mantle with subducting slab fluids source. The granitic rocks have an asthenospheric-lithospheric mantle with metagreywaky continental crust contamination. We suggest that appinitic magma formed by roll-back of subducted Neo-Tethys oceanic lithosphere and granitic magma formed by breck-off the subducted Neo-Tethyan oceanic slab. The asthenospheric upwelling would also have provided enough heat for the partial melting of continental crust. It is possible that magma formed at a great depth and underwent a long period of fractional crystallization. Finally, evolved granitic rocks have been placed at a shallow depth of the crust.

The Aralan intrusion is located about 35 Km southwest of Marand in northwestern part of the Central Iran. This intrusion is composed of Codomain granitoid rocks that intruded into Precambrian Kahar Formation. The composition of the intrusion varies from Alkali feldspar granite to granite and mineralogically includes quartz, alkali feldspar, plagioclase, zircon and opaque minerals. These rocks display granular, perthitic, granophyric and myrmekitic textures. Evidences such as decreasing in grain size, cracking, fracturing, twin bending, kinking, recrystallization and myrmekitization indicate the role of shear zone in the study area, which has partly caused some deformation in the study rocks. This intrusion, based on textural evidence, is a hypabyssal intrusion and probably emplaced at low level crust. The study rocks have hypersolvus to transsolvus alkali feldspar textures, calc-alkaline to high K calc-alkaline affinity, high LILE+LREE and low HREE. Comparing with the standard spider diagram pattern for several tectonic setting, the Aralan intrusion is compatible with post-collision and within-plate tectonic setting. The study rocks belong to the A2-type subgroup of A-type granitoids. The Aralan intrusion is associated with tensional phase after finishing the compressional phase of Pan-African orogeny.

Study area is located in Eastern Azerbaijan province, 27 km far from east Bostanabad, and the north of Qarehchaman geological map. According to field tracking and surveys, host rock of mineralization is a Subvolcanic rocks of Oligocene period. Based on microscopic studies, the most important of supergene part, containing primary oxide minerals (Magnetite), secondary oxide minerals (Malachite, Hematite and Goethite) and also sulphide minerals such as Chalcocite, Covellite, Pyrite and insignificance Chalcopyrite. Among the most important alterations, argillic, silicification, carbonization and propylithic can be noted. Geochemical studies shows that host rock of mineralization with Monzosyenitic composition, placed in high chalc-alkaline to shoshonitic and metaluminous range. Formation environment of host rock of mineralization is a volcanic arc of subduction zone that confirmed by normalized rare earth elements diagrams.

The Kimia copper area is located in the Eocene volcano-sedimentary complex northwest of Bardskan in Razavi Khorasan Province. The geology of the area includes volcanic rocks with andesite-basalt composition, conglomerate with andesite fragments, nummulitic limestone and tuffaceous sandstone. Mineralization is found in andesite and conglomerate units as well as at the border between these units in the form of vein-veinlets, disseminated, replacement and open space filling. Primary minerals are chalcocite, pyrite, and secondary minerals are malachite, caveolite, and iron oxide. The faults in this region are formed in two directions, northeast-southwest and northwest-southeast, with a slope of 45 degrees. The main veins in this zone are calcite-quartz-pyrite, calcite-chalcocite and calcite-barite-pyrite. Alterations related to veins are siliceous and carbonate and are related to igneous, propylitic, carbonate and chloritic units. The amount of copper element ranges between 6950 and 47935 ppm and other elements have low values. Based on fluid inclusion study, the minimum formation temperature ranges between 228 and 368 °C and the salinity is between 10.4 and 16.9 percent. Based on the evidence of the host rock, structure, textures and existing alterations, copper mineralization in Kimia area is Manto type.

The Balestan iron deposit is located about 55 km southeast of Urmia city. The main host rock is the quartz sericite schist unit of the Early Precambrian age. Major mineralization occurred along the schistocytes of the host rock. However, open space filling structure is also abundantly observed in the fault zones. Based on field evidence and microscopic studies, the dominant iron mineralization is in the form of magnetite, which is observed along with pyrite and chalcopyrite. Geochemical investigations revealed that the distribution patterns of trace elements and major oxides are very similar to other hydrothermal iron deposits. The microthermometric studies of fluid inclusions shows an average homogenization temperature and salinity of about 276°C and 7.3 wt% NaCl equivalent, respectively.The variation trends in salinity and Th of fluid inclusions can be explained by a cooling and pressurization of ore-bearing fluids. Also, these data show that the Balestan iron ore deposit is located within the field of mesothermal ore deposits.

Kalateh Pialeh prospect area is located in the Kopeh Dagh zone, approximately 15 km northeastern of Esfarayen city. The area is composed of sedimentary rocks deposited during the Jurassic, Cretaceous, and Tertiary periods, which include microconglomerate, dolomitic limestone, sandy limestone, limestone, conglomerate, and marl. Mineralization occurs as epigenetic deposits hosted by dolomitic limestone and limestone. Two mineralization stages were identified. The first stage consists of a pyrite-galena-sphalerite assemblage with replacement and breccia textures, and the second stage comprising a galena-sphalerite assemblage with vein-veinlet, open space filling, and replacement textures. Dolomite and calcite are the most abundant gangue minerals associated with lesser amount of quartz and barite. Main alterations consist of calcitization and dolomitization. Galena mineral exhibits maximum geochemical anomalies of 1843 ppm for zinc, 7 ppm for arsenic, and 11 ppm for copper. Microthermometric studies on primary fluid inclusions (LV) reveal homogenization temperatures ranging from 180°C to 265°C for stage 1, and from 167°C to 214°C for stage 2. Salinities for these stages were found to be between 7.8 wt.% to 14.5 wt.% NaCl equiv., and 11.7 wt.% to 12.2 wt.% NaCl equiv., respectively. Based on evidence such as structurally controlled mineralization, the type of alterations and their linear expansion, simple mineralogy of ore, geochemistry, and fluid inclusion data, Kalateh Pialeh prospect area is similar to lead-zinc epithermal deposits.

The Gano bauxite deposit is located 90 km northeast of Semnan city in the eastern Alborz Mountains, northern Iran. The bauxite ores occur as stratiform discrete lenses with a length of 6 km and thickness of 2–20 m along the contact between carbonates of the Elika Formation and shale, sandstone, siltstone, and coal of the Shemshak Formation. Mineralogical analyses revealed that the bauxite ores consist of diaspore, hematite, kaolinite, chlorite, anatase, illite, zunyite, goethite, quartz, and dolomite minerals. Fluctuations of the groundwater table level, acidic atmospheric waters, and an increase in pH of the weathering solutions close to carbonate bedrocks played an important role in the concentration of Fe-poor ores in the upper parts and Fe-rich ores in the lower parts of the studied profile. An increase in oxidation, the possible presentence of secondary phosphate minerals, fluctuations of the groundwater table level, and the role of carbonate bedrock as an active buffer played an important role in the extent of Ce anomaly in the ores (0.79–12.25). The pH variations of weathering solutions, fluctuations of the groundwater table level, the role of carbonate bedrock as a geochemical barrier, and simultaneous precipitation of Fe-bearing minerals and preferential scavenging of LREE(La–Eu) by hematite played an important role in the distribution and fractionation of rare earth elements in the bauxite ores. According to geochemical considerations (Eu/Eu* vs. TiO2/Al2O3 and Sm/Nd bivariate diagrams), the Gano bauxite deposit probably derived from the weathering of intermediate igneous rocks.

The carbonate deposits of the Taleh Zang Formation are exposed extensively in the southeastern to northern Lorestan zone, SW Iran. The thickness of the shallow water carbonate Taleh Zang Formation in Ritt Anticline is 84.5 meters. It overlies on top of the turbidity Amiran Formation and it is overlain by the clastic-dominated Kashkan Formation. Petrographic examinations revealed seven facies deposited in tidal flat, lagoon, shoal and open marine. Detailed analysis of sedimentary facies indicates that in the Late Paleocene interval, the depositional system of the Taleh Zangi Formation was a ramp carbonate platform. Changes in the depositional facies and cycle stacking patterns indicate one transgressive-regressive sea-level cycle from the bottom to the top of the section, which is equivalent to the last eustatic sea level rise in the Late Paleocene (Thanetian).  This depositional sequence is separated by type 2 and 1 sequence boundaries at its lower and upper boundaries, respectively. Elemental geochemical evidence indicates a closed to weakly open digenetic system, with low water-rock interaction for carbonates of the Taleh Zang Formation. The relatively open digenesis system in this formation could be due to the influence of meteoric fluids in the erosional discontinuity at the border between the two formations, the Taleh Zang and Kashkan formations.

Marshoun area located 120Km Southeast of Zanjan, is a part of the Tarom-Hashtjin metallogenic-magmatic subzone within the Alborz-Azarbaijan zone. Similar to most parts of the Alborz-Azarbaijan zone, the Eocene-Oligocene volcanic and the intrusive rocks of this subzone were formed as a result of the Alpine orogenic phase, which has a close spatial and temporal relationship with metallic mineralization (Kouhestani et al., 2019). Several studies have been conducted on metallic mineralizations in different parts of the Tarom-Hashtjin subzone. The petrological studies carried out in this subzone are mainly focused on intrusive rocks (e.g., Seyed Qaraeini et al., 2020) and volcanic rocks' geochemical and petrological characteristics have been less considered. Marshoun area is composed of volcanic-sedimentary sequences which are hosts for Pb-Zn-Cu mineralization (Kouhestani et al., 2019). A detailed scientific study has not been done on the lithological sequence and their geochemical and petrological characteristics in the Marshoun area so far. In the present study, the lithological and geochemical characteristics including Sr, Nd, and Pb isotopic data, as well as the tectonomagmatic environment of the volcanic rocks of the area have been investigated.

During fieldwork, a 1:25000 geological map prepared from different lithological units of the area and over 30 samples were taken. Also, 17 thin sections for petrographical studies, 10 samples for chemical and 4 samples (2 andesites and 2 dacites) for iaoopic analyses. Chemical analyses (XRF and ICP–MS methods) were carried out at Zarazma Laboratory, Tehran, Iran., and isotopic studies (i.e. Nd, Sr, and Pb isotope studies at Institute of Geology and Geophysics, Chinese Academy of Geosciences, Beijing, China.

The predominant rock units in the Marshoun area are Eocene acidic tuffs, dacitic-rhyodacitic lava, and occasionally ignimbrite at the base and alternation of intermediate tuff with minor andesite and basaltic andesite intercalation in the top, along with some intrusive rocks with (Zajkan intrusion), and some gabbroic dykes.Zajkan intrusion including pyroxene quartz monzodiorite, quartz monzodiorite, and granodiorite composition intruded acidic volcano-sedimentary rocks with a total thickness of 930 meters can be divided into 9 parts.Volcanic rocks of the Marshoun area are classified as rhyolite, rhyodacite, dacite, andesite, basaltic andesite, and trachy-andesite with high-K calc-alkaline affinity. Dacitic-rhyodacitic rocks have porphyritic, flow, and spherolitic textures, composed of plagioclase, quartz, alkali feldspar, and mafic minerals (amphibole and biotite) set in a quartz-felspathic groundmass whereas, andesitic rocks show porphyritic, glomeroporphyritic, and amygdaloidal textures, composed of plagioclase and mafic minerals (amphibole and some pyroxene) set in a fine-grained and occasionally microlithic groundmass.All samples under study on primitive mantle normalized spider diagrams, have similar patterns indicative of their genetic relations. LILEs and HFSEs.negative anomalies are remarkable features of these rocks. Chondrite-normalized REE patterns demonstrate a relatively steep to low slope pattern with LREE enrichment and a high ratio of LREE/HREE, (La/Yb)N, and (La/Sm)N ratio between 3.8-30.1 and 1.2-8.25, respectively. On tectonomagmatic setting discrimination diagrams, volcanic rocks of the Marshoun area have been formed in an active continental margin tectonic setting. Isotopic data of Sr (0.70485-0.70622), Nd (0.512695-0.712733), and Pb (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb between 18.743-18.803, 15.5938-15.6112 and 38.8138-18.0721, respectively) point to dominant role of mantle in the formation of the investigated rocks. According to the Pb isotopes, the area's acidic rocks originated either from a more enriched mantle or were contaminated by crustal materials during ascending magma.

As the geochemical data indicate the primary magma of Marshoun volcanic rocks is generated by the partial melting of subcontinental metasomatized mantle lithosphere as a result of the subduction process within the continental margin environment. According to data obtained from the present study as well as the previous research, it can be concluded that the result of the subduction of the active continental margin and the shortening of the crust in Alborz during the Eocene gave rise to the thickening of continental crust and further led to the separation and subsidence of the lower part of the subcontinental lithospheric mantle (delamination).As a result of this event, the ascending of asthenosphere currents has led to an increase in the thermal gradient and partial melting of the subcontinental lithosphere and generation of basic magma which during ascending contaminated by crustal materials. Finally, the differentiation process led to the formation of intermediate and acidic rocks.

The Fatehabad Cu deposit is located in the Khorasan Razavi province, 35 km SE of the Torbat-e Heydariyeh and in the Khaf-Kashmar-Bardaskan metal belt. The vein and veinlet mineralization consist of chalcopyrite, pyrite, magnetite, chalcocite, bornite, covellite, malachite and iron oxides associated with siliceous-sericite, argillite and propylitic alteration in the volcanic rocks formed parallel to the sub-faults that branch off from the Dorouneh fault. The similar pattern of REE and trace elements in the mineralized veins and associated volcanic rocks suggests an magmatic-hydrothermal origin of the ore elements. In the vein system of Fathabad district, quartz, pyrite, chalcopyrite, and magnetite veins with propylitic alteration in the early stage of mineralization, quartz, pyrite, chalcopyrite and magnetite veins with sericite alteration in the main stage of mineralization and quartz, pyrite and chalcopyrite veins were identified along with argillic and iron oxide alterations. Calcite veins along with sericite and iron oxide alterations were also identified in the late stage of mineralization. The enrichment of trace, LREEs/HREEs ratio, positive Eu anomalyand negative Ce anomaly, indicate reducing conditions and a high pH of the mineralized fluids. Fluid inclusion studies with low salinity (13.9 to 4.74 wt% NaCl eqv.) and low temperature (111 to 192 oC) indicate dilution and mixing of the sulfur- and element-rich magmatic-hydrothermal fluid with meteoric water, leading leaching and precipitation of trace, rare and copper elements. The δ34S isotopes values (-1.58 to -2.86‰) in the chalcopyrite minerals indicate the magmatic origin of sulfur. The geology, geochemistry, and fluid inclusions evidences indicate that the Fathabad Cu deposit is belong to epithermal style mineral systems.

The aim of this research is the geochemical study of the major and trace elements of the alteration systems in the Kamar-Gov district (south of Hashtjin, Ardabil province). The rock units of  the studied area include volcanic rocks with the composition of basaltic-trachy andesite to rhyolite and crystal vitric-tuff with Eocene and Oligocene age. These rocks have calk alkaline and shoshonitic affinity and belong to post-collisional arc tectonic setting. In the Kamar-Gov district, the alteration zones include silicic, sericitic (quartz + muscovite + pyrite ± illite ± rutile), sericite-argillic (quartz + sericite + kaolinite + dolomite), intermediate argillic (quartz + kaolinite + illite), advanced argillic (quartz + kaolinite + alunite + diaspore ± anatase ± muscovite), and chloritic (quartz + chlorite + illite). The distribution pattern of the normalized-BSE major and trace elements and the mass change calculations (volume factor method) show that the silicic and advanced argillic alteration zones have more elemental depletion and different distribution patterns from the parent rock. However, chloritic, intermediate argillic, and sericite-argillic alterations have relatively little mass change and almost similar distribution patterns to the primary parent rock. The major elements like Ca, Mg, Al, Na, and Fe have frequently depleted. Ti shows slight depletion. K has frequently enriched. Trace elements such as Zr, Nb, Sc, and Th have mass reduction. Co, Cr, Ni, and Rb have experienced depletion and enrichment processes. Sr and V show relatively high depletion. Sb, S, and As (chiefly) have enriched. LREEs have depleted more than HREEs. Elements like Pb, Zn, and Cu only in the siliceous and sericite-argillic zone show enrichment. This research shows that factors like pH of hydrothermal fluid and primary rock-forming and secondary minerals resulting from alteration have caused differences in the behavior and concentration of elements in different alteration zones in the Kamar-Gov district.