Economic Geology
Hadi Mohammadian; vartan simmonds; kamal Siahcheshm
Abstract
The Sarikhanloo area is located within the Qaradagh metallogenic zone in northwest Meshgin Shahr. Igneous rocks cropped out in this area include successions of Paleocene-Eocene pyroclastic rocks (tuff and andesitic-dacitic lavas with intercalations of ignimbrite) and basaltic andesite lava flows. Igneous ...
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The Sarikhanloo area is located within the Qaradagh metallogenic zone in northwest Meshgin Shahr. Igneous rocks cropped out in this area include successions of Paleocene-Eocene pyroclastic rocks (tuff and andesitic-dacitic lavas with intercalations of ignimbrite) and basaltic andesite lava flows. Igneous rocks show high-K calc-alkaline to shoshonitic nature and are mainly metaluminous, formed in a post-collisional uplift tectonic setting. Hydrothermal activities in this area brought about formation of vast silicic veins and caps, along with silicic, propylitic, phyllic (non-pervasive) and intermediate argillic alterations around the veins, as well as intermediate to advanced argillic alteration halos at the margins of silicic caps. Ore minerals in the silicic veins includes pyrite, arsenopyrite and Fe-oxides, accompanied by minor malachite, formed during four mineralization stages. Fluid inclusion studies indicate that the homogenization temperature of fluid inclusions ranges from 175 to 355 °C, considering the low pressure of fluid inclusions (≤ 0-40 bars), can signify the fluid temperature at the time of entrapment. The estimated salinity values are between 0.2 and 3 wt% NaCleq.
Economic Geology
nasrin khajehmohammadlou; Ali Asghar Calagari; Kamal Siahcheshm; Ali Abedini
Abstract
The Aghbolagh iron-copper skarn is located in ~21 km north of Oshnavieh, southwest of West-Azarbaidjan province. The intrusion of Cretaceous granitic body into the Cambrian Barut, Zagun, and Lalun Formations (carbonate, shale, and sandstone) was accompanied by development of calcic-type skarn, hornfels, ...
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The Aghbolagh iron-copper skarn is located in ~21 km north of Oshnavieh, southwest of West-Azarbaidjan province. The intrusion of Cretaceous granitic body into the Cambrian Barut, Zagun, and Lalun Formations (carbonate, shale, and sandstone) was accompanied by development of calcic-type skarn, hornfels, and marble in the study area. The garnets of the Aghbolagh skarn belong to solid solution series of grossularite-andradite in which andradite is the dominant phase (>80%). These garnets are isotropic and lack zonation. The pattern of REE distribution in these garnets shows the enrichment of LREE relative to HREE and also the occurrence of negative anomalies of Eu/Eu* and Ce/Ce*. The comparison of the distribution pattern of REE in garnets with those in igneous (granite and monzonite) and sedimentary (carbonates and sandstones) rocks demonstrates that the REE in garnets were derived mainly from the igneous rocks rather than the sedimentary units. The increase in Pr/Yb ratios in parallel with increase in the ƩREE is indicative of the magmatic origin of the ore-forming fluids in the Aghbolagh skarn. However, the lack of sensible variations between Ce/CE* and ƩREE values indicate that the meteoric waters might have also played a part in skarn-forming fluids at Aghbolagh.
Economic Geology
S. Maleki; A. A. Calagari; K. Siahcheshm; S. Alirezaei
Abstract
Khak Sorkh iron deposit located about 42 km northwest of Nadushan town in Yazd Province. Host rock include upper Triassic-Jurassic limestone which are intruded by Oligo-Miocene granitoid bodies. Mineralization is dominated by magnetite, and serpentine is the main waste mineral. Skarn mineral assemblages ...
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Khak Sorkh iron deposit located about 42 km northwest of Nadushan town in Yazd Province. Host rock include upper Triassic-Jurassic limestone which are intruded by Oligo-Miocene granitoid bodies. Mineralization is dominated by magnetite, and serpentine is the main waste mineral. Skarn mineral assemblages include clinopyroxene, garnet, tremolite phlogopite and epidote. The characteristics of mineralization are: magnetite mineralization in two generations, presence of serpentine as the main waste mineral, hornfelsed greywacke units which come between intrusive bodies and skarned limestone units, absence of obvious zoning in endoskarn and exoskarn parts, presence of Ni-Co-As sulfides, high amount of Zn, As, Co and Mn in magnetite geochemical results and the increasing Fe along with decreasing Mg contents in magnetite at both deposit and crystal scales from primary to secondary types. Minor elements contents of geochemical results have been used for distinguishing of different mineral deposits (e.g, Dare et al., 2012; Dupuis and Beaudoin, 2011; Nadoll et al., 2012) and they are in good accordance to hydrothermal and skarn type deposits like: low contents of Cr (less than 10 ppm), high contents of Mg (2.2 to 7.5 ppm), low TiO2 (from 0.01 to 0.3 ppm), low amounts of incompatible elements including Ag (
R. Masoumi; A. A. Calagari; K. Siahcheshm; S. Porkhial
Abstract
The geothermal field at the south of Mount Sabalan is a part of the geothermal system of the Sabalan volcano region wherein manifestations of young volcanic activities including hot springs and surficial steams are observable. The surficial hydrothermal fluids in this area show maximum temperature of ...
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The geothermal field at the south of Mount Sabalan is a part of the geothermal system of the Sabalan volcano region wherein manifestations of young volcanic activities including hot springs and surficial steams are observable. The surficial hydrothermal fluids in this area show maximum temperature of 77°C, pH range of 6.4-7.4, and maximum TDS values of 7006 mg/l. Generally, these waters are divided compositionally into two groups. The first are mainly Na-Cl waters while the second are chiefly Ca-Na-HCO3 waters. The rare and heavy elements in these fluids are principally boron, lithium, rubidium, cesium, arsenic, and mercury whose maximum abundances are 33511, 14265, 3418, 10366, and 5 ppb, respectively. Considering the lithologic units in the area, vast hydrothermal fluid activities, and wide-spread alteration zones, boron-bearing minerals were regarded to be as the major sources of this element, which was leached and transported by geothermal fluids. Boron concentration in these fluids is controlled in part by fixation in clay minerals. Further considerations in geochemical behavior of the rare and heavy elements in this geothermal field demonstrated that lithium and rubidium were absorbed by quartz and clay minerals, respectively at temperatures <300°C, and also Cl- ion played a main role for transportation of mercury. Although the concentration values of B, Hg, As, and Li in the geothermal fluids of the studied area are not high enough to warrant the potential economic mineralization for these elements, the presence of these elements in these hot waters was recognized to be very consequential from two environmental respects; firstly because these geothermal waters are being directly used for swimming and bathing in the area, and secondly they may act as hazardous pollutant sources when mixed with the underground and drinking waters.
SH Safari; A Asghari Moghaddam; A Nadiri; K Siahcheshm
Abstract
Arsenic is one of the most toxic and dangerous soluble substances in natural water. It has long-term ill effects on human health. Arsenic-contaminated water resources have been reported from many parts of the world and Iran, particularly from the Kurdistan province in the west of the country. The aim ...
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Arsenic is one of the most toxic and dangerous soluble substances in natural water. It has long-term ill effects on human health. Arsenic-contaminated water resources have been reported from many parts of the world and Iran, particularly from the Kurdistan province in the west of the country. The aim of this study is to identify the source of arsenic and mechanisms of its release into groundwater resources of the Chahardoli plain aquifers. Groundwater resources in this plain supply much of the water needs for drinking, agriculture and industry. Therefore, 31 water samples were collected from the plain aquifer and chemically analyzed for major and minor ions in the Hydrology Laboratory of Earth Sciences Department of the Tabriz University. Also, the trace elements were analyzed in the Kurdistan Waste Water Organization Laboratory. The results show high arsenic concentrations in the groundwater of the area. The highest arsenic concentration (270 µg/L) is related to a well located in the northwest part of the area which supplies water for agricultural purposes of Delbaran sector. According to the results obtained from multi-variable and graphical methods, there is a meaningful correlation between arsenic and major ions such as Na and K as well as silica, indicating that the source of arsenic is from volcanic rocks. It is therefore a geogenic rather than an anthropogenic phenomenon. The mechanism of arsenic releases into the water can be related to competitive adsorption of dissolved SiO2 in adsorption sites such as oxides of iron, aluminium and manganese.
R Ferdowsi; A.A Calagari; M.R Hosseinzadeh; K Siahcheshm
Abstract
Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry ...
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Astarghan area is located in ~ 50 km of north of Tabriz, southeast of Kharvana, East-Azarbaidjn. The area is a part of Gharadagh- Arasbaran metallogenic belt. The most important units in the area is a hypabyssal prophyritic to granular granodioritic intrusive body of Oligo-Miocene and flysch- type sedimentry sequence of limestone, limy sandstone and marl (Paleocene-Eocene). Intrusion of the stock into the sedimentary rocks caused them to convert into a series of metasomatites and contact metamorphic rocks. Geostatistic studies on stream sediments and heavy mineral were done and include data processing, (i.e. normalization, univariate and multivariate analysis), and ultimately preparation of anomaly maps. The correlation coefficients among elements were determined. Elements that show positive correlations with gold are Cu, Hg, Pb, As, Sb, Ag, Bi and Mo. The results of preliminary regional geochemical explorations have led to discovery of two anomalous zones for gold; grade 1 and grade 2. The anomalies were verified by studies on heavy minerals in stream sediments and mineralized and altered samples taken from gold anomalous zones. The most important indentified heavy minerals include magnetite, malachite, gold, micaseous hematite, pyrite, galena, cerussite, pyrite- limonite, goethite, limonite, barite, hematite, pyrite- oxide which are affiliated with alteration and mineralzation zones. The major alterations in the area are argillic, sericitic and propylitic developed along the vein’s walls. Field and analytic studies done on samples taken from the gold anomalous zones led to identification of epithermal gold veins having over 4.5 ppm gold grade. The concordance of anomaly map with tectonic map and altered zones indicate that the faulted and fractured zones have played a crucial role in creation of gold anomalous zones. The incorporation of these data in the area led to introduction of several anomalous zones belonging to Au, Ag, Cu, As and Pb that can be used as passfinders for epithermal gold.
