Papers by Hossein Kouhestani
Frontiers in Earth Science
Tashvir and Varmazyar deposits are part of the epithermal ore system in the Tarom–Hashtjin Metall... more Tashvir and Varmazyar deposits are part of the epithermal ore system in the Tarom–Hashtjin Metallogenic Belt (THMB), NW Iran. In both deposits, epithermal veins are hosted by Eocene volcanic-volcaniclastic rocks of the Karaj Formation and are spatially associated with late Eocene granitoid intrusions. The ore assemblages consist of pyrite, chalcopyrite, chalcocite, galena, and sphalerite (Fe-poor), with lesser amounts of bornite and minor psilomelane and pyrolusite. Fluid inclusion measurements from the Tashvir and Varmazyar revealed 182–287 and 194–285°C formation temperatures and 2.7–7.9 and 2.6–6.4 wt.% NaCl equivalent salinities, respectively. The oxygen isotope data suggested that the mineralizing fluids originated dominantly from a magmatic fluid that mixed with meteoric waters. The sulfur isotope data indicated that the metal and sulfur sources were largely a mixture of magma and surrounding sedimentary rocks. LA-ICP–MS zircon U–Pb dating of the granitoid intrusion at Tashvir...
Petrology, 2018
Khanchay-Aliabad area as a part of Tarom magmatic belt contains some shallow depth intrusions whi... more Khanchay-Aliabad area as a part of Tarom magmatic belt contains some shallow depth intrusions which are intruded the Eocene volcanic- sedimentary rocks and have very close association with Cu mineralization. The Eocene volcanic- sedimentary rocks include alternation of basalt, basaltic andesite and andesite, various kinds of tuff, tuffaceous sandstone, sandstone, siltstone and occasionally shale. Petrographical studies demonstrate that intrusions are pyroxene quartz monzonite and olivine gabbro in composition. The Khanchay pyroxene quartz monzonite have porphyritic to porphyroidic, hetero-granular to sereitic, ophitic and sub- ophitic textures and composed of plagioclase, clinopyroxene, hornblende, quartz, K-feldspar and biotite. The Aliabad pyroxene quartz monzonite shows porphyritic to porphyroidic textures composing of plagioclase, clinopyroxene and hornblende in the quartz- feldspatic matrix. The Khanchay olivine gabbro is characterized by the presence of coarse grained granular...
Journal of Economic Geology, 2018
Introduction The Qarachilar Cu-Mo-Au occurrence is located in the Arasbaran ore zone (AZ), NW Ira... more Introduction The Qarachilar Cu-Mo-Au occurrence is located in the Arasbaran ore zone (AZ), NW Iran, some 70 km north of Tabriz. The AZ is characterized by occurrence of different types of mineralization and hosts many Cu-Mo porphyry (PCD), Cu skarn, and epithermal Au deposits (Jamali et al., 2010; Jamali and Mehrabi, 2015). The main rock unit exposed in the area is Qaradagh batholith (QDB). A variety of porphyry and vein-type Cu–Mo–Au mineralization are associated with QDB. The most pronounced occurrences are in Qarachilar, Qara-Dareh, Zarli-Dareh, Aniq and Pirbolagh. This type of mineralization can be followed in other parts of northwest Iran, such as Masjed-Daghi porphyry Cu–Au deposit and Mivehrood vein-type Au mineralization in the southwest of the QDB, the Sungun PCD and the related skarn in its southeast, and Astamal Fe skarn deposit in the south of the QDB. To date, no detailed study has been undertaken to understand the characteristics of the Qarachilar occurrence and its mi...
Journal of Economic Geology, 2020
Introduction The Qoyjeh Yeylaq Pb-Zn (Ag) deposit located 120 km southeast of Zanjan, is situated... more Introduction The Qoyjeh Yeylaq Pb-Zn (Ag) deposit located 120 km southeast of Zanjan, is situated in the Urumieh-Dokhtar magmatic arc. apart from Prior to this research no work has been published on Pb-Zn (Ag) mineralization at the Qoyjeh Yeylaq except for small scale geological maps of the area, i.e. 1:250,000 geological maps of Kabudar Ahang (Bolourchi and Hajian, 1979), 1:100,000 geological maps of Marzban (Majidifard and Shafei, 2006) and a number of unpublished Pb-Zn exploration reports. The present paper provides an overview of the geological framework, mineralization characteristics, and results of geochemistry study of the Qoyjeh Yeylaq deposit with application to ore genesis. Identification of these characteristics can be used as a model for exploration of this type of Pb-Zn (Ag) mineralization in this area and elsewhere. Materials and methods Detailed field work has been carried out at different scales in the Qoyjeh Yeylaq area. About 26 polished- thin and thin sections fr...
Journal of Economic Geology, 2020
Introduction Fe skarn deposits are one of the important Fe deposits in the Zanjan province which ... more Introduction Fe skarn deposits are one of the important Fe deposits in the Zanjan province which have been exploited in recent years. The Qozlou Fe deposit is one of these Fe skarn deposits which is located at 65 km west of Zanjan. In this area, alternation of micro-sparitic limestone, marly limestone, shale and sandstones of Upper Cretaceous were intruded by Late Eocene granitoids. This event caused to metamorphism contact and it caused the formation of Fe mineralization. Some of the Fe skarn deposits in the Zanjan province were studied during the past few years (e.g. Nabatian et al., 2017) and valuable information is present about their geological and mineralization characteristics. However, Qozlou granitoid and Fe deposit have not been studied yet. In this research, petrology and geochemistry of the Qozlou granitoid along with petrographic characteristics, mineralogy, structure and texture of Fe deposit and thermodynamic conditions for formation of contact metamorphic rocks have ...
Journal of Economic Geology, 2020
Introduction Iron oxide-apatite deposits (IOA) are considered to be Kirune-type iron ores which h... more Introduction Iron oxide-apatite deposits (IOA) are considered to be Kirune-type iron ores which have been formed during Proterozoic to Tertiary eras in different parts of the world. They usually have a connection with calc-alkaline volcanic rocks (Hitzman, 2000). Apatite occurs as a major constituent of these deposits which is accompanied with magnetite and some actinolite. One of the most important features of these deposits (Frietsch and Perdahl, 1995) is higher concentration of REEs. There are some iron oxide-apatite deposits in the Tarom-Hashtjin magmatic-metallogenic belt, northwestern Iran. The Golestan Abad iron oxide-apatite deposit is one of the IOA deposits at the Tarom-Hashtjin belt which is located about 30 km east of Zanjan. The Golestan Abad deposit was studied during the exploration studies, but its geological characteristics, mineralogy, texture, geochemistry and genesis have not been studied yet. Materials and methods This research study can be divided into two part...
منطقه آقکند در فاصله 48 کیلومتری شمال زنجان واقع شده است و بخشی از زیرپهنه طارم- هشتجین در پهنه ... more منطقه آقکند در فاصله 48 کیلومتری شمال زنجان واقع شده است و بخشی از زیرپهنه طارم- هشتجین در پهنه ساختاری البرز باختری- آذربایجان محسوب میشود. کانهزایی مس در این منطقه بهصورت رگه کوارتز- فلوئورین مس دار در میزبان گدازههای بازالت آندزیتی ائوسن رخداده است. بر اساس بررسیهای میکروسکپی، کانههای فلزی در منطقه آق کند شامل کالکوپیریت و به مقدار کمتر اسپکیولاریت، کانیهای مرحله سوپرژن و کانیهای باطله کوارتز، فلوئورین و کلریت هستند. مهمترین بافتهای کانسنگ شامل دانه پراکنده، رگه-رگهچه ای، برشی، پرکننده فضای خالی، جانشینی، کوکاد، قشرگون، گل کلمی و پرمانند است. شش مرحله کانه زایی در رخداد معدنی مس آق کند، قابل تشخیص است. این مراحل با رگه- رگهچه های فلوئورین (مرحله اول) آغاز و به ترتیب با ته نشست کوارتز و کالکوپیریت در رگه ها و سیمان گرمابی برش ها (مرحله دوم)، رگه- رگهچه های کوارتز- اسپکیولاریت (مرحله سوم)، رگهچههای منفرد و یا دسته رگهچه های نیمه موازی تا متقاطع کوارتز (مرحله چهارم)، بافت رگه- رگهچه ای و پرکننده فضاهای خالی کلریت (مرحله پنجم) و سرانجام تشکیل مالاکیت و هیدروکسیدهای ...
Mineralium Deposita, 2011
Analytical methods and procedures Analytical procedures for U-Pb zircon chronology Four samples f... more Analytical methods and procedures Analytical procedures for U-Pb zircon chronology Four samples from the Chah Zard volcanic complex including andesite-trachyandesite, porphyritic daciterhyodacite and rhyolite porphyry rocks were selected for U-Pb zircon geochronology. Zircons were obtained from crushed rocks by handpicking under binocular microscope after sieving, and conventional heavy-liquid and magnetic separation techniques. The zircons were mounted in epoxy, polished, and then photographed in transmitted and reflected light for identification of analyzed grains. Representative backscattered electron (BSE) and cathodoluminescence (CL) images were then made of the zircons before analysis to reveal their internal structures. The zircons are mostly euhedral to subhedral grains and preserve subtle to delicate normal or oscillatory zoning characteristic of igneous growth. No evidences of truncation or embaying by either younger zircon overgrowth or recrystallization (as thicker rims) were observed in the zircon grains. The zircons were dated on an Agilent 7500cs quadrupole ICP-MS with a 193 nm coherent Ar-F gas laser and a Resonetics M50 ablation cell at the University of Tasmania, Hobart, Australia. The LA-ICP-MS analyses followed Meffre et al. (2008) who established the methods similar to those outlined in Black et al. (2004) and Paton et al. (2010). The down hole fractionation, instrument drift and mass bias correction factors for U-Pb ratios on zircons were calculated using 2 analyses on the primary (91500 standard of Wiendenbeck et al. 1995) and 1 analysis on each of the secondary (TEMORA standard of Black et al. (2003) and GJ1 standard of Jackson et al. (2004)) standard zircons analyzed at the beginning of the session and every 12 unknown zircons (roughly every 1/2 hour) using the same spot size and conditions as used on the samples. Additional secondary standards (the Mud Tank zircon of Black and Gulson 1978) were also analyzed. The correction factor for the 207 Pb/ 206 Pb ratio was calculated using 3 large spots of NIST-610 analyzed at the beginning and end, and corrected using the values recommended by Baker et al. (2004). Element abundances on zircons were calculated using the method outlined by Kosler (2001) using Zr as the internal standard element, assuming stoichiometric proportions and using the 91500 to standardize correction for mass bias. The ages were calculated using ISOPLOT 3.00 (Ludwig 1998). Uncertainties in ages are quoted at the 95% confidence level (2 σ).
DOAJ (DOAJ: Directory of Open Access Journals), Sep 1, 2022
Halab Au occurrence, 120 km southwest of Zanjan, is located in the Sanandaj–Sirjan Zone and is pa... more Halab Au occurrence, 120 km southwest of Zanjan, is located in the Sanandaj–Sirjan Zone and is part of the Takab–Takht-e-Soleyman–Angouran Metallogenic Zone (TTAMZ). TTAMZ is one of the essential metallogenic zones in Iran (Daliran, 2008). The Zarshouran Au deposit (Daliran et al., 1999, 2002; Mehrabi et al., 1999; Asadi et al., 1999, 2000), Aghdarreh Sb–Au deposit (Daliran, 2008), and Angouran Zn–Pb deposit (Daliran et al., 1999, 2013; Gilg et al., 2006; Boni et al., 2007; Zhuang et al., 2019) along with some Fe, Pb–Zn, Au, Cu and Mn mineralization were found within this zone. Apart from small scale geological maps of the area, i.e., 1:250,000 geological map of Takab (Alavi and Omidi, 1976) and 1:100,000 geological map of Takab (Fonoudi and Hariri, 1999) and several unpublished exploration reports (Karbasi, 2015; IMIDRO, 2017), before this research no work had been done on Au mineralization at Halab. The present paper provides an overview of the geological framework, the mineraliza...
The Chah-Bagh gold occurrence is located in Muteh mining district, in the central part of the San... more The Chah-Bagh gold occurrence is located in Muteh mining district, in the central part of the Sanandaj-Sirjan zone. Gold mineralization occurs in ductile to ductile-brittle shear zones and is comparable with orogenic gold deposits. Silicification and sulfidization are the most important hydrothermal alteration features in the inner parts of altered shear zones and coincide most closely with the ore-bearing zones. Principal ore minerals are pyrite, chalcopyrite, arsenopyrite and native silver. Silver commonly occurs both as native Ag grains (ca. 5 μm in diameter) intimately associated with siliceous gangue and as invisible silver within sulfides. The maximum concentration of invisible silver occurs in chalcopyrite. Although native gold was not identified in the siliceous gangue and in the sulfide minerals and their alteration products, electron microprobe analyses confirmed the occurrence of invisible gold within sulfides. Two phases of gold mineralization occurred in the Chah-Bagh a...
Geochemistry: Exploration, Environment, Analysis
The major target of this research is the classification of pyrite types using fractal and stepwis... more The major target of this research is the classification of pyrite types using fractal and stepwise factor analyses in the Chah Zard ore deposit, Central Iran. The ore occurs within a breccia/vein type and the major ore mineral hosting gold mineralization is pyrite. In this study, data were selected using optical, scanning electron microscopy (SEM) and backscattered electron observations as well as laser ablation-inductively coupled plasma–mass spectrometry (LA-ICP–MS) analysis. Conventional interpretations represent four gold-bearing pyrite types of various textures including fractured and porous Py1, oscillatory-rimmed and simple-zoned Py2, colloform Py3 and inclusion-rich Py4. The stepwise factor process was performed on the centred log ratio (clr) transformed data in two phases and Au was grouped with As, Te, Ni and Co in the second factor from the second stage (F2-2). Also, C-N fractal modelling was performed on the As, Au, Te and F2-2 values, all of which demonstrate multifract...
Kosaj Fe occurrence, 100 km southwest of Zanjan, is located in the Sanandaj–Sirjan zone and is pa... more Kosaj Fe occurrence, 100 km southwest of Zanjan, is located in the Sanandaj–Sirjan zone and is part of the Takab–Takht-e-Soleyman–Angouran metallogenic zone (TTAMZ). TTAMZ is one of the most important metallogenic zones in Iran (Daliran, 2008). The Zarshouran Au deposit (Daliran et al., 1999, 2002; Mehrabi et al., 1999; Asadi et al., 1999, 2000), Aghdarreh Sb–Au deposit (Daliran, 2008), and Angouran Zn–Pb deposit (Daliran et al., 1999, 2013; Gilg et al., 2006; Boni et al., 2007; Zhuang et al., 2019) along with some Fe, Pb–Zn, Au, Cu and Mn mineralization were found within this zone. Aside from small scale geological maps of the area, i.e., 1:250,000 geological maps of Takab (Alavi and Omidi, 1976) and 1:100,000 geological maps of Takht-eSoleyman (Babakhani and Ghalamghash, 1996) and several unpublished exploration reports (Rostami, 2014), before this research no work had been done on Fe mineralization at Kosaj. The present paper provides an overview of the geological framework, the ...
Ore Geology Reviews, 2013
Arabian Journal of Geosciences
The Qozlou Fe skarn deposit is located at the Abhar–Mahneshan belt of the Central Iranian Zone. I... more The Qozlou Fe skarn deposit is located at the Abhar–Mahneshan belt of the Central Iranian Zone. It is associated with Upper Eocene porphyritic granite that intruded into the Upper Cretaceous impure carbonaceous rocks. The Qozlou granite has high-K calc-alkaline affinity and is classified as subduction-related metaluminous I-type granitoids. Skarn aureole in the Qozlou is composed of endoskarn and exoskarn zones, with the exoskarn zone being the main skarn and mineralized zone. It includes garnet skarn, garnet-pyroxene skarn, pyroxene skarn, epidote skarn, and pyroxene-bearing marble sub-zones. The Qozlou Fe deposit is 300 m long and 5–30 m wide. Magnetite is the main ore mineral associated to pyrite, chalcopyrite, and pyrrhotite. Garnet, clinopyroxene, actinolite, epidote, calcite, and quartz occur as gangue minerals. Covellite, hematite, and goethite were formed during the supergene processes. The ore and gangue minerals have massive, banded, disseminated, brecciated, vein–veinlets...
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Papers by Hossein Kouhestani