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

Porphyry deposits are very important as they contain very large reserves of copper and valuable secondary elements such as molybdenum and gold. Copper-molybdenum or quartz monzonite porphyry deposits are usually structurally related to the magma arc associated with the upper parts of the subduction zone of the continental margin, and copper-gold or porphyry diorite deposits usually form in association with the subduction zone of the island arc (Sillitoe, 2010; Park et al., 2021).
Kahang Cu-Mo deposit is located in the middle section of the Urumieyh-Dokhtra magmatic arc. In 2001, Kahang was identified by processing satellite imagery data and mapping hydrothermal alteration by Rio Tinto Mining and Exploration Limited company. Then, a detailed exploration was carried out by Dorsa mining company from 2002 to 2007 and about 40 million tons of copper ore with a grade of 0.6 percent was established (Asadi, 2007). Since 2008, extensive deep drilling has been performed by the National Iranian Copper Company to increase the proved reserve. The main focus of the previous researchers at the Kahang deposit was mostly based on conceptual studies on magmatic character and hydrothermal alterations (Ayati et al., 2008; Harati, 2011; Azadi et al., 2014; Komeili, et al., 2017; Aliyari et al., 2020). In the present research, ASTER satellite imagery data, geological maps, as well as geochemical and magnetic data were processed and used to identify optimum exploration criteria at the Kahang porphyry Cu-Mo deposit and other similar deposits.

Near-surface mineralization at Kahang deposit is related to altered and brecciated quartz monzonite dykes, and deeper than 200 m is associated with altered quartz monzonite porphyry intrusions showing calk alkaline characteristics. The extensive hydrothermal alteration, from the center to the margin of the Kahang deposit, are phyllic, argillic, and propylitic alterations. Mineralization is mostly related to strong phyllic and potassic alterations.

Detailed geological maps of Kahang area were used to identify geological exploration criteria. Aster satellite imagery data of the area was used to identify hydrothermal alterations. ICP analytical results of elements such as Cu, Mo, Zn, and Pb were used to create uni-element and additive index multi-element geochemical anomaly maps to identify geochemical exploration characteristics. In total 16 rock samples were collected for petrographic studies and XRF analysis. A number of 568 magnetic measurements were used to create magnetic anomalies associated with favorable subsurface hydrothermal alterations possibly associated with Cu-Mo mineralization.

ICP analytical results of the soil samples were used to identify geochemical exploration criteria at Kahang deposit. Basic statical studies were applied to these data to identify the variation of Cu, Mo, Pb, and Zn concentrations in the soil samples that could be associated with subsurface mineralization. Mult-elements additive index geochemical maps of the analytical results of the soil samples showed a Cu-Mo enrichment zone in the central part of the hydrothermal alteration and a Pb-Zn depletion zone in the margin. Based on these additive index maps three porphyry centers were identified at the Kahang deposit for further exploration.

By processing ground magnetic data of the eastern porphyry center at Kahang deposit, residual total magnetic intensity and upward continuation magnetic maps were created to identify magnetic signatures possibly associated with mineralized hydrothermal alterations. These maps showed an ellipsoid-shaped low magnetic anomaly in the eastern porphyry center associated with phyllic alteration hosting Cu-Mo mineralization. These low magnetic anomalies can be used to identify zones of subsurface mineralization at Kahang deposit.

In this research, remote sensing, geological, geochemical, and geophysical studies showed three porphyry centers at Kahang deposit. The world-class economic mineralization only occurred in the eastern porphyry center due to the presence of extensively strongly altered and brecciated quartz monzonite porphyry units showing low magnetic signatures and high Cu-Mo additive index anomalies. By comparing the low magnetic anomalies, high Cu-Mo anomalies, alteration zonation, brecciated rock units, and favorable structures, successful drilling targets can be identified to test subsurface mineralization at Kahang deposit. The integration of this information along with the geochemical and primary drilling information were used to plan systematic drilling. Most of the holes drilled in this zone at depths greater than 150 meters encountered economic mineralization of copper (approximately 0.5%) and molybdenum (approximately 700 ppm). The magmatic arc of Urmia-Dokhtar is considered the most important copper (molybdenum, gold) porphyry province in Iran. Most of the known large porphyry deposits of Iran, such as Sarcheshmeh and Meidok, are located in the southeast of this magmatic arc, and Songun is located in its northwest. In the central part of the Urmia Dokhtar magmatic arc, which is located in Isfahan and Central provinces, no similar deposit was reported prior to the discovery of Kahang deposit. Therefore, these studies have shown that the middle part of this arc may have the potential for many hidden porphyry mineralizations like Kahang deposit. Therefore, the exploration criteria identified in this study can be used for the exploration of similar deposits in this area at various stages of exploration, from identification to detailed exploration.

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 studied section is located in the 113Km east of Birjand (25Km Asadiyeh City) and east of Pating Village. The mentioned sequence, aged Late Cretaceous, is totally 246m in thickness and mostly consists of thick and medium bedded limestones along rock units. The lower boundary has been limited by basal red conglomerate and the upper boundary has been covered by red-colored sandstone unit. In This research, based on both field and laboratory studies, the main components of carbonate rocks include both skeletal and non-skeletal grains and totally 7 carbonate microfacies have been determined which have been deposited within 3 facies belts including tidal flat, Semi-restricted lagoon and shoal. According to the obtained evidences from the microfacies analysis, the suggested depositional model for the Pating section is a homoclinal ramps type carbonate platform. All of the microfacies are mainly deposited in the inner part of the ramp slope. The obtained geochemical data from carbonate samples analysis indicate a calcitic original mineralogy and dominance of a closed diagenetic system for the studied sequence. Also, according to the geochemical data, a temperate climatic condition could be considered for the formation environment of this sequence which is confirmed by the Late Cretaceous Palaeogeographic global map. The studied limestone samples have been widely affected by different diagenetic processes that the most important of which are micritization, cementation, mechanical and chemical compaction, dissolution, neomorphism, replacement, fracturing and vein-filling cements that have been formed in a variety of marine, meteoric, shallow burial and uplift diagenetic environments.

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.

Bitumen is a mixture of oxidized hydrocarbons with color, hardness, specific gravity and various metamaterials that are in solid or semi-solid forms and can be dissolved in Carbon disulfide (CS2). To evaluate the physical and chemical characteristics of bituminous deposits in Lorestan sedimentary basin (a part of the Folded Zagros zone), 6 fresh and non-weathered bitumen samples were collected from the veins and inside the mines of three areas with high potential of bitumen, including the northern region of Kohdasht, western Poldokhtar and southeastern Sepiddasht. The surface studies of above mentioned area, indicates the appearance of bitumen (tar mats) occurred in Amiran Formation. According to the analysis, the average amount of oxygen, nitrogen and carbon in the studied samples is 6.30%, less than 1% and 74.47% respectively, the average percentage of mineral ash and moisture of the samples is 6.4% and 0.8 percent respectively which indicates the very favorable quality of the studied bitumens .The solubility of studied bitumens in CS2, benzene and ethanol solvents shows that most of these bitumens have compounds with high molecular weight (asphaltene molecules) and low amounts of hydrogen (average 6.02). This example is also consistent with this conclusion. X-ray fluorescence analysis (XRF) on 6 bitumen samples from the studied area shows that Al2O3, SiO2 and Fe2O3 oxides are more abundant than other oxides. This issue can be due to the formation of this mineral in the host rock of the Amiran shale formation, which is rich in the mentioned elements. The values of CaO and K2O in the analyzed bituminous samples can be due to the formation of this mineral from the underlying formations (Ilam and Gurpi) which have found their way into the Amiran formation after formation and migration. The ratio of Ni vs V of the samples of the studied area is low (Ni/V <1) and has an average of 0.57%, so their rock of origin was somewhat carbonate-shale. The current studies reveal that, the origin of the studied bitumen started from deeper and older shale sediments (Ilam and Gurpi Formations), in which the deeper bitumen has migrated upward and washed the younger hydrocarbons to shallower formations and earth surface accumulation.

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.

Sagh mineral occurrence is located southeast of Torbat-e-Heydarieh, Khorasan Razavi province, and in the eastern part of the Khaf-Kashmar-Bardeskan magmatic belt. The rock units of area are divided into two categories: intrusions (monzonite, monzodiorite, diorite, and syenite) in the southern half, and conglomerate in the northern half. One square kilometer of continuous mineralization may be observed as stockwork, while there are other locations where it has a linear trend and is supported by intrusive rocks. Primary minerals include specularite, chalcopyrite, pyrite, galena, and sulfosalt, and secondary minerals include malachite, goethite, hematite, chalcosite, caveolite, and anglesite. The mineralization textures are vein-veinlet, disseminated, replacement, and cloform, mainly with a strong chloritic-silicified alteration. The average amount of copper is 0.8 with a maximum of more than 3%, the average amount of silver is 24.4 with a maximum of more than 113 ppm, and the average amount of gold is 44 with a maximum of 250 ppb. The average amount of lead is 761 ppm with a maximum of 0.4% and the average amount of zinc is 430 ppm with a maximum of 0.1%. The formation temperature of ore-forming fluid is between 159 and 328 °C and the salinity is between 7.2 and 16.7 wt.% equiv. NaCl. The mixing of magmatic fluids with meteoric waters with low temperatures and salinity was the most important mechanism of mineral formation. Based on the evidence of tectonic setting, lithology, type of alteration, shape, and state of mineralization, and the presence of abundant specularity with copper, silver, and gold anomalies, probably the Sagh area is iron oxide Cu-Ag±Au type. 

The geological settings, hydrothermal alteration, and mineralizing fluid compositions vary among the deposits of “IOCG-type” (Hitzman et al., 1992; Sillitoe, 2003). However, they belong to a family of Cu ±Au deposits that include substantial hydrothermal alkali (Na/Ca/K) alteration and a lot of low-Ti iron oxide (magnetite and/or hematite). According to Williams et al. (2005), these deposits likewise exhibit strong structural constraints and a temporal but not a tight geographical relationship with igneous rocks. They formed in rift or subduction settings (Hitzman, 2002) from the Late Archean to the Pliocene (Groves et al., 2010).
Sagh mineral occurrence is located the southeast of Torbat-e-Heydarieh, Khorasan Razavi province, and in the eastern part of the Khaf-Kashmar-Bardeskan magmatic belt (Fig.1). This belt has a high potential for iron oxide copper-gold type deposits and sometimes skarn and porphyry copper (Karimpour, 2004).
The purpose of this research is geological studies and determine the relationship of intrusions with mineralization, examine the total paragenesis sequence, geochemistry, fluid inclusions studies and finally determine the mineralization model, and the formation of mineral occurrences in the Sagh area, for the first time is done.

To investigate the lithology, alteration, and mineralization of the Sagh area, 61 samples were taken mainly from the intrusions. 32 samples for the thin section and 10 samples for the polished thin section and polished block were selected, prepared, and studied. Then, the geological and alteration-mineralization map with a scale of 1:5000 was prepared in Arc GIS software. Furthermore, for geochemical studies of mineralization zones and veins, 24 samples were taken and sent to the Zarazma laboratory for analysis. Analysis was done by the ICP-OES method. Furthermore, 11 samples were selected for gold analysis with Fire assay, and sent to Zarazma laboratory. Using a cooling and heating system made by Linkam Company, model THM 600, microthermometric tests and salinity determination were performed on 2 wafers of quartz minerals and 31 fluid inclusions at Ferdowsi University of Mashhad.

The rock units of the area are divided into two categories: subvolcanic and plutonic intrusions in the southern half and conglomerate units in the northern half. Intrusive rocks are composed of monzonite, monzodiorite, diorite and syenite. Mineralization can be seen in the form of stockwork in a wide and continuous zone with an area of about one square kilometer, but in some places, it has a linear trend (NE-SW and NW-SE trend) which is hosted by intrusive rocks. Primary minerals include specularite, chalcopyrite, pyrite, galena, and sulfosalt, and secondary minerals include malachite, goethite, hematite, chalcosite, covellite, and anglesite. Vein-veinlet, disseminated, replacement, and cloform mineralization textures are seen, with a dominant chloritic-silicified alteration. The average concentration of copper is 0.8%, with a maximum concentration of more than 3%, silver is 24.4 ppm, with a maximum concentration of more than 113 ppm, and gold is 44 ppb, with a maximum concentration of more than 250 ppb, according to geochemical data. The average amount of lead is 761 ppm with a maximum of 0.4% and the average amount of zinc is 430 ppm with a maximum of 0.1%. Based on fluid inclusions studies, the formation temperature of ore-forming fluid is between 159 and 328 °C, and the salinity is between 7.2 and 16.7 wt.% equiv. NaCl.

Comparing the characteristics of Sagh prospect area with other copper-bearing deposits shows that this area is very similar to iron oxide copper-gold deposits. An empiric definition of IOCG deposits is summarized as having the following five characteristics (Williams et al., 2005): (1) copper, with or without gold, as economic metals, (2) hydrothermal ore styles and strong structural controls, (3) abundant magnetite and/or hematite, (4) Fe oxides with Fe/Ti ratios greater than those in most igneous rocks and bulk crust, and (5) no clear spatial associations with igneous intrusions as, for example, displayed by porphyry and skarn ore deposits.
Sillitoe (2003) proposed a close genetic relationship between IOCG deposits in northern Chile, and dioritic plutons. Mineralization in the Sagh area has a close relationship with monzonitic, monzodiorite, and diorite, which are similar to Kuh-e-Zar, Bahariyeh, Namaq, Fadiheh, Chenar, and other KKBMB deposits (Table 3).
The main alteration related to mineralization in the Sagh is propylitic-silicified, and its propylitic alteration is characterized by chlorite mineral. Extensive chlorite alteration in the Sagh area is similar to Monteverde deposit in Peru (Vila et al., 1998), Mont-del-Aigle in Canada (Simard et al., 2006), Kuh-e-Zar Tarbat Heydarieh (Karimpour et al., 2017), and other IOCG type deposits in the KKBMB belt (Almasi et al., 2015; Taghadosi and Malekzadeh Shafaroudi, 2018; Najmi et al., 2023; Sahebi Khader et al., 2021; Behnamnia et al., 2023) and Qala Zari (Karimpour, 2005) in the Lut block, where the temperature and salinity of ore-fluid are lower than some IOCG type deposits in the world.
Based on the available evidence, the mineral occurrence of the Sagh includes 1) the presence of oxidant intrusions formed in the subduction zone in the KKBMB, 2) mineral paragenesis of specularity, chalcopyrite, pyrite, and galena, 3) structural control of mineralization, 4) copper, silver, gold, and lead geochemical anomaly, 5) chloritic-silicified alteration, which is very compatible with iron oxide copper-silver-gold systems. The location of this area in the KKBMB belt, which has great potential for IOCG deposits, and near other IOCG deposits that have many similarities (Almasi et al., 2015; Karimpour et al., 2017; Sahebi Khader et al., 2021; Najmi et al., 2023), is a confirmation of this claim.
Although monzonitic, monzodiorite, diorite, and syenitic intrusions are the host rock of mineralization and mineralization is controlled by structures and faults, this magmatism can be represented of source rock at deep. The mineral paragenesis of the Sagh and the abundance of specularity with sulphide minerals of copper, lead, and silver, which are associated with quartz and chlorite, show that mineralization generated from a high fO2, Fe-Si rich ore fluid.
The metal originated from an oxidan magmatism from deep, and moved up through faults, joints, and fractures. The mixing of magmatic ore solution with higher temperature and salinity with meteoric water with lower temperature and salinity has finally led to the deposition of sulfides, and the formation of mineralization. Temperature-salinity and alteration evidence show that we are currently in the upper parts of the system, and we need more information. The relevance of this magmatic belt in eastern Iran as a significant metallogenic zone for deposits of copper, gold, and silver is growing as more and more IOCG mineral occurrences are found there.

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.

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.

The felsic intrusive rocks in the Piranshahr plutonic complex consist of three groups: syenite, nepheline-syenite, and alkali-feldspar granite. They are co-genetic and formed approximately 40 million years ago. Textural relationships, major oxides, and trace element composition of the selected felsic rock samples were studied using SEM, EPMA, and LA-ICP-MS methods. In the studied samples, apatite appears as euhedral to subhedral crystals with prismatic forms and has a homogeneous texture without zonation. The low amounts of MnO and the REE pattern of apatites confirm their magmatic nature, indicating that post-crystallization processes did not affect the composition of apatites. All apatite crystals fall into the fluorapatite category. The amounts of fluorine and chlorine vary in different felsic rocks, and the F/Cl ratio decreases from granites towards syenites and nepheline-syenites. The determination of the apatite saturation temperature indicates that alkali feldspar granites have a higher crystallization temperature range (858-844°C) than both syenites (818-783°C) and nepheline syenites (668-610°C). Analyzing the manganese levels in the examined apatites suggests a consistent oxidizing setting with minimal fluctuations in fO2 conditions (logfO2= -8 to -9.8). Trace elements in different apatites show significant differences; for instance, apatites in granitic samples are enriched with HFSE and rare earth elements (REE), while apatites in nepheline-syenites have a higher concentration of components such as silica, Cr, Ni, and V. The composition of trace elements and the F/Cl ratios in apatites demonstrate consistent variations and alignment with the host rock composition. The results of the apatite mineral composition confirm previous petrological findings regarding the impact of volatile phases separation on magmatic evolution in the Piranshahr felsic rocks.

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 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.

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.