Environment
Akram Abdolahadi; Seyed Jamal Sheikhzakariaee; Abdollah Yazdi; Seyed Zahed Mousavi
Abstract
The Plio-quaternary sub-volcanic domes are the products of magmatism in the Turkish-Iranian plateau in the collision zone between Eurasia and Arabia. Intermediate-felsic volcanic rocks are found 50 km west of Ardabil. These volcanic domes make a significant part of the Sabalan volcanic, a Plio-quaternary ...
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The Plio-quaternary sub-volcanic domes are the products of magmatism in the Turkish-Iranian plateau in the collision zone between Eurasia and Arabia. Intermediate-felsic volcanic rocks are found 50 km west of Ardabil. These volcanic domes make a significant part of the Sabalan volcanic, a Plio-quaternary stratovolcano in northwest Iran. The igneous rocks (adakitic) include dacite, trachyte, andesite, trachy-andesite, and trachydacite, associated with ignimbrite and pyroclastic equivalents. They mainly comprise phenocrysts and a microcrystalline groundmass of pyroxene, amphibole, and plagioclase, with biotite and titanomagnetite. These rocks are enriched in Light Rare Earth Elements (LRREs) and Large Ion Lithophile Elements (LILEs) and depleted from Heavy Rare Earth Elements (HRREs) and High-Field Strength Elements (HFSEs). In these rocks, the SiO2 content is 56-66 wt%, Na2O is > 3.5 wt%, Al2O3 > 15 wt%, Yb < 0.2 ppm, and Y < 7 ppm, which are typical of high silica adakitic rocks. The initial ratios of the 143Nd/144Nd range from 0.5127 to 0.5129 and the initial ratios of 87Sr/86Sr for the adakites range from 0.7035 to 0.7060, reflecting the heterogeneity of the mantle and different degrees of crystallization. These geological, geochemical, and Sr, and Nd isotopic data indicate that these rocks belong to the post-collisional adakite type, and are derived from low-degree partial melting of a subduction-metasomatized continental lithospheric mantle (eclogite or amphibolite garnet). In the studied area, mineralization related to Plio-quaternary adakitic rocks has not been observed.
Reza Nouri; Mehran Arian
Abstract
In this research work, the fractal modeling of Au anomalies in the Chaapaan 1:100,000 sheet (NW Iran) is conducted through an investigation of the concentration-distance to lineament (C-DL) relationship. The classification of Au anomalies is based on their proximity to major lineaments. Stream sediment ...
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In this research work, the fractal modeling of Au anomalies in the Chaapaan 1:100,000 sheet (NW Iran) is conducted through an investigation of the concentration-distance to lineament (C-DL) relationship. The classification of Au anomalies is based on their proximity to major lineaments. Stream sediment data is utilized to identify Au anomalies, and the C-DL model demonstrates a strong correlation between the main gold anomalies and their distance from remote sensing lineaments. The findings indicate that gold anomaly values exceeding 12 ppb are found within a distance of less than 1 km from the remote sensing lineaments, establishing a significant association between fault structures and mineralization. Moreover, the average distances to remote sensing lineaments are found to be less than 1.3 km, underscoring the suitability of the C-DL fractal modeling for identifying hydrothermal gold deposits.
Saeed Saadat
Abstract
In this work, the results of nearly 1400 stream sediment sample analysis are processed to better understand environmental pollution caused by mining activities in Eastern Iran. The stream sediment samples are analyzed for As, Sb, Fe, Cr, Ni, Co, Cu, Zn, Pb, Sr, and Hg. The mean concentration of these ...
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In this work, the results of nearly 1400 stream sediment sample analysis are processed to better understand environmental pollution caused by mining activities in Eastern Iran. The stream sediment samples are analyzed for As, Sb, Fe, Cr, Ni, Co, Cu, Zn, Pb, Sr, and Hg. The mean concentration of these elements follows the decreasing order of Fe > Sr > Zn > Cr > Cu > Ni > Co > Pb > As > Sb > Hg. Based on the assessment of pollution, extremely severe enrichment factor Co (EF > 25), and high enrichment of Sb, Hg, Cr, and Sr (EF > 10) are detected. Specifically, Cr and Ni in southern stream sediments show significantly elevated concentrations compared to the others. The range of the contamination factor varies from CF < 1 to CF > 6 for most elements. Geo-accumulation index shows high contamination levels by Cr and Co and high to severe contamination by Sb. The risk indices are low for all elements except for As and Co in the eastern part of the studied area. Principal component analysis, Spearman correlation coefficient, and cluster analysis are used to demonstrate similarities and differences between the elements. Pollution indices show that contaminations in some samples are the consequence of gold mineralization. The high correlation of Cu, Zn, and Sb is due to the sulfide mineralization of gold. The high correlation of Cr and Ni corresponds to ultramafic rocks and ophiolitic series. This study focuses on the impact of mining activities, even at early stages on the dispersion of some heavy metals in stream sediments. Based on the results presented here, while most contamination in the target area is rooted in geochemical and mineralization processes, mining activity also contributes to soil pollution for certain elements such as Cu and Zn. The most affected stream sediments are those within the vicinity of mining areas and attention should be paid to potential risks to the environment particularly during gold mining activities.
A. Zolfaghari; N. Barzegar; M. Amini
Abstract
The gypsum mineralization occurred in the form of Satin Spar and Selenite in the south and southwest of the Fars province in the folded Zagros zone. In this region, Satin Spar mineralization has been formed as stratiform between the red marl and siltstone units of Late Miocene–Pliocene in Agha ...
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The gypsum mineralization occurred in the form of Satin Spar and Selenite in the south and southwest of the Fars province in the folded Zagros zone. In this region, Satin Spar mineralization has been formed as stratiform between the red marl and siltstone units of Late Miocene–Pliocene in Agha Jari, Bakhtiari, and the Gachsaran formations. The reserves of Satin Spar in this area are at least 200,000 tons. Satin Spar due to its chatoyancy, has been able to distinguish itself from gypsum. This beautiful light phenomenon (chatoyancy) results from the regular and parallel arrangement of the Satin Spar fibers. The mineral was first identified by its physical properties, and then by the X-ray diffraction analysis. They were also examined by scanning electron microscopy for its structure and also the structure of fiber crystals and their optical properties. In order to examine the polishing condition of Satin Spar, several samples of this gemstone were also selected for fantasy and Cabochon cut. For the first time in Iran, the exploration of Satin Spar gemstone in the Fars region can be a model for its discovery in the other evaporative formations in the country.
M. Yazdi; A. Bahrami; Z. Alaminia; H. Jamali; M. A. Mackizadeh
Abstract
This research work introduces the Early Triassic, Late Triassic-Early Jurassic, and Early Cretaceous silica-rich sand levels at east and central Alborz, Kopeh-Dagh, and Central Iran, and compares them with the Permian silica-rich sand level in the Chirouk mine at east Iran. Ghoznavi and Gheshlaq loose ...
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This research work introduces the Early Triassic, Late Triassic-Early Jurassic, and Early Cretaceous silica-rich sand levels at east and central Alborz, Kopeh-Dagh, and Central Iran, and compares them with the Permian silica-rich sand level in the Chirouk mine at east Iran. Ghoznavi and Gheshlaq loose sand in Alborz (Early Triassic-Early Jurassic), Soh quartzite in Central Iran (Early Triassic-Early Jurassic), Firuzeh sands with mud levels in Kopeh-Dagh (Early Cretaceous), and Sarnaza in Central Alborz (Late Triassic-Early Jurassic) silica-rich levels are studied in this work. Geochemical analysis and physical factors of the studied silica levels are checked regarding grain size, heat resistance, and steel molding. The laboratory and industrial methods used for washing, sieving, heating, molding, and controlling the purity of refractory sand levels show that the main difficulty of these levels within the molding process is intra-grain cracks, which spoils the alloy’s final product. The Early Triassic level in the Ghoznavi area has a high purity but the average grain size is below the steel molding standard. The Late Triassic to Early Jurassic levels in Alborz and Central Iran are oversize with grain cracks but can be fixed by the industrial refinery methods. The size of Early Cretaceous refractory sands of Firuzeh (Kopeh-Dagh) is below the standard molding process; it can be fixed by the washing and refinery methods. The systematic exploration methods show that all the studied silica-rich sand levels have an intra-grain collapse within the molding process. Final test shows that the Chirouk silica-rich levels can be used as refractory sand for cast and molding in the steel industry.
S. Moghaddam; S. Dezhpasand; A. Kamkar Rohani; S. Parnow; M. Ebrahimi
Abstract
Protection of water resources from contamination and detection of the contaminants and their treatments are among the essential issues in the management of water resources. In this work, the time-lapse electrical resistivity tomography (ERT) surveys were conducted along 7 longitudinal lines in the downstream ...
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Protection of water resources from contamination and detection of the contaminants and their treatments are among the essential issues in the management of water resources. In this work, the time-lapse electrical resistivity tomography (ERT) surveys were conducted along 7 longitudinal lines in the downstream of the Latian dam in Jajrood (Iran), in order to detect the contamination resulting from the direct injection of a saltwater solution in to the saturated zone in the area. To investigate the pollutant quantities affecting the resistivity of this zone, the temperature and electrical conductivity measurement were carried out using a self-recording device during 20 days (before and after the injection). The results obtained from the self-recording device measurements and ERT surveys indicated that in addition to the salt concentration changes in water, the resistivity changes in the saturated zone were dependent on other factors such as the lithology and absorption of contaminants by the subsurface layers. Furthermore, the expansion of contamination toward the geological trend, sedimentation, and groundwater flow direction of the area were shown.
Feridon ghadimi; Mohammad Ghomi; Abdolmotaleb Hajati
Abstract
Altogether 20 groundwater samples were collected around the Lakan Pb and Zn mine in Iran. Samples were analyzed for 8 constituents including Fe, Pb, Hg, Mn, Zn, CN, SO4 and Cl using standard method. The results show that the average concentrations of constituents were 0.01, 0.60, 0.10, 0.01, 0.40, 35, ...
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Altogether 20 groundwater samples were collected around the Lakan Pb and Zn mine in Iran. Samples were analyzed for 8 constituents including Fe, Pb, Hg, Mn, Zn, CN, SO4 and Cl using standard method. The results show that the average concentrations of constituents were 0.01, 0.60, 0.10, 0.01, 0.40, 35, 0.01 and 5.95 mg/kg for Fe, Mn, Pb, Zn, Hg, SO4, CN and Cl, respectively. The computed contamination index ranged between 2.38 and 443. It was concluded that contamination index shows a medium to high contaminated situation for Pb and Hg in groundwater around the tailings dam. Based on a multivariate analysis, four main sources of these hydrochemical data were identified. (1) Zn, Mn, TDS and SO4 have both natural and anthropogenic sources; (2) Hg constituent represents a natural source and Pb shows a anthropogenic source due to Lakan mine; (3) CN and Fe have anthropogenic source and mainly originated from the plant processing; (4) Cl represents a natural source.
