In this paper, tectonic and geothermobarometric environments have been studied with respect to the combination of pyroxene, olivine and plagioclase in volcanic rocks in the southeast of Bam. The combination of volcanic rocks in the region consists of olivine basalt, basalt, alkaline basalt, andesite, trachyandesite and pyroxene andesite. This combination is the result of the processes of crystallization and sometimes contamination. Plagioclase, clinopyroxene, olivine, and amphibole constitute the major minerals (rock forming minerals) in these rocks. Porphyritic to mega-porphyritic textures with microlithic, glumero-porphyritic and amigdaluidal matrix are observed. Based on the thermometric calculations, plagioclase, pyroxene, and olivine minerals and the rocks of this region are crystallized at a pressure of 1.5 to 7 kb and temperatures ranging from about 700˚C to 1250˚C.
Kamoo region (northeast of Isfahan) has an anticline structure with a northwest-southeast trend. The exposed part of this anticline consists of siltstone-sandstone and Jurassic shale, which is located below the Cretaceous formation as an unconformity. Penetration by magmatic masses (dikes) and mineralization events are mainly related to fault systems and fractures in the region and follow the trend of the anticline. In addition, the intensity and variety of alterations are affected by tectonic factors, with alteration and metasomatic haloes having developed next to crushed areas. The alteration process is the main controller of mineral mass grade in the study area; therefore, iron grade in the Kamoo ore has increased by the effects of alteration. The alteration effects include propylitic haloes, iron hydroxides (limonite), and clay mineralization (argillic). The host rock consists of Jurassic shales with siltstone, sandstone, and Cretaceous limestone. Calcareous formations adjacent to granodiorite masses are the main hosts of iron skarns. The results of this study showed that the mineral samples from Kamoo were relatively rich in Light Rare Earth Elements (LREEs); the average La/Yb ratio is about 18.61 and Eu anomaly is between 0.52 and 1.94. Based on the findings of this study, the origin for Kamoo skarn was consistent with the model presented by Meinert, and the region’s mineralization and alteration characteristics correspond to the conditions prevailing in oceanic subduction and back-arc basin environments.
Identification and determination of areas with mineral potential is one of the major and important applications of remote sensing in the field of mineral exploration. The aim of the present study was Identification of hydrothermal ultrason region using Landsat multispectral satellite imagery and hyperion hyperspectral imagery. To conduct this research, first the Advanced Space Borne thermal reflection radiometric data and the base metal mapping of the harvest were examined. Using principal component analysis using the key spectral change properties of key minerals, PC 2 enhanced the altered regions. Then we studied the MF spectral library and laboratory spectra of samples in the study area. In this study, two different methods, principal component analysis (PCA) and matched filter processing (MF), were compared and combined for mapping. In both methods, the key properties of changing the range of minerals in the study area were used. The results of the present study showed that from the top of the deposit to the bottom, the type of mineralization is gradually increasing. Chalcopyrite spraying gradually decreases from the depth of the deposit to the outer regions and vice versa, the amount of pyrite spraying increases. In Sungun, the main mineralization of copper in the second (main) stage of the activity of mineralized solutions has taken place, during which chalcopyrite has been extensively left in the form of vessels and sprays in rocks. Molybdenite is formed in a wide range of second stage mineralization processes in several successive phases. In the early processes, this mineral is sprayed and less in the form of veins and in later stages more in the form of veins. Thus, the copper-molybdenum porphyry deposit of Sungun Ahar, with a very high reserve of 7.1 billion tons and an average copper grade of 0.75 ٪ And molybdenite by-mineral in the early 80's will certainly be exploited among the largest copper mines in Iran.
O batólito de Shirkuh, Yazd, faz parte da zona estrutural central do Irã, localizada a sudoeste da província. O batólito é composto por cinco unidades de rochas, a saber monzogranito, granodiorito, quartzo monzonito, quartzo monzodiorito e sienogranito. O batólito, após cortar a formação de bandas nay (Triássico Superior), possui calcários cretáceos e uma unidade de arenito e conglomerado (Cretáceo Inferior). deitado no topo como uma inconformidade angular, provavelmente remonta ao Jurássico. Investigações experimentais e de campo revelaram vários minerais acessórios na massa de granito, incluindo granada, turmalina, anfibólio, zircão, esfeno, apatita, biotita, moscovita e epídoto. A granada, a turmalina e os anfibólios foram investigados por um Electron Microprobe (EMP), revelando que a massa de granito era do tipo almandina, grossular e uvarovita, a turmalina do tipo rossmanita e foitita e anfibólios dos tipos tschermakita e hornblenda.
The study area is located 5.5 km north-east of Kamo County and 30 km north-east of Meymeh, Isfahan. Kamo Index comprises an anticline with a northwest-southeast trend, the outcrop of which consists of siltstone-sandstone and Jurassic shale rocks that lie along a cretaceous unit. Based on field studies as well as petrographic and geochemical investigations, mineral assemblages and minerals in the area include chalcopyrite, pyrite, marcasite, and magnetite as primary ores and malachite, bornite, covellite, chalcocite, hematite, goethite, and hydrous iron oxides as secondary ores. The secondary ores have been formed by oxidation and biogenic processes. The primary textures are granular, disseminated, vein-shaped, and layered and the secondary textures are boxed and martitized, shear zones, replacements, and veins. Tectonic, metamorphic, and oxidation factors are involved in the formation of these textures. Due to tectonic activity in this area and the presence of faults, replacement, vein, and shear textures, which have developed after mineralization, are observed. Among alterations, hematite, propylitic, sericitic, limonitic, and kaolinitic are highly prevalent and they are important in the formation of iron deposits. The sub-alkaline granitoids of the region are related to the continental subduction-zone orogenic series. Studies on the decomposed iron samples from Kamo show that most of the samples are in the sub-alkaline series and the chemical and mineralogical composition of the magma derived from this series is calc-alkaline with a large amount of iron. According to mineralogical, lithological, and geochemical evidence and based on isotopic results, Kamo deposit is a skarn-type deposit.
The intrusive rocks of Naqadeh are features of Laramide magmatism in the Sanandaj–Sirjan zone. According to petrographic studies, the composition of intrusions consist of acidic, intermediate, and basic rocks. including syenogranites, monzogranite, granodiorites, quartz diorites, quartz monzonites, quartz monzonite, quartz syenite, and olivine gabbro—in order of abundance. Minerals forming intrusive rocks include alkali feldspar (orthoclase and microcline), quartz, plagioclase (andesine to anorthite), amphibole (magnesiohornblende to tschermakite hornblende), pyroxene (diopside), olivine (hyalosiderite to hortonlite), apatite, titanite, zircon, muscovite, and opaque minerals. The chemical analysis of the granitoids revealed their potassium-rich calc-alkaline nature, falling within the meta-alumin to per-alumin range in terms of alumin saturation. Tectonomagmatic diagrams for the studied rocks suggest that they are compatible with granitoids of the continental-subduction zone. Primitive-mantle- and chondrite-normalized spider diagrams indicated no depletion in any elements, exhibiting a negative overall slope which is consistent with subduction patterns (negative Ta, Ti, Zr anomalies, and positive K anomaly). Overall, a review of field observations, mineralogy, geochemistry, and diagrams illustrating the sources of granites showed that the intrusive rocks in the study region are, in fact, I-type granite and that the magmatism is a result of the subduction of the oceanic crust, Neotethys, under the Iranian continental crust.
The study area is located 5 km southwest of Mahdasht city in Karaj on the Urmia-Dokhtar magmatic arc. In this area, Eocene volcanic and pyroclastic rocks are observed including basaltic andesite lavas, andesite, Trachyandesiticand trachyte lavas, tuff, and ignimbrite, along with plutonic rocks. There are two spectra of basic and acidic for the rocks in the area, of which basic rocks are chemically calc-alkaline in nature.Among the signs of subduction rocks in the area are enrichment in the Ta, Nb, and Ti lavas, as well as the anomaly of the HFSE index relative to the LILE of incompatible elements content. The geochemical and petrogenetic studies indicate the origin of the area’s plutonic rocks and the role of differential crystallization accompanied by the crustal rocks-contamination and digestion of magma in the evolution of the magma forming these rocks. This magma has been originated from the low-grade partial melting of an enriched mantle origin beneath the continental lithosphere with the lherzolite garnet composition at a depth of 100 to 110 km in a post-collision tensile environment. Investigating the fluids involved in the region, the homogenization temperature with the temperature of copper veins formation is between 120 to 306 ° C, with the salinity percentage varying between 6.45 to 15.96% of sodium chloride weight. Accordingly, this metamorphic hydrothermal orebodyis located in the mesothermal category. The presence of sub-faults, joints, and cracks in the host rock has provided a low-pressure environment for a proper place for copper mineralizationas veins.
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