Mineralization and fluid evolution of epithermal base metal veins from the Aqkand deposit, NW Iran

Kouhestani, Hossein; Azimzadeh, Amir Morteza; Mokhtari, Mir Ali Asghar; Ebrahimi, Mansour

doi:10.1127/njma/2017/0036

Cited by 16 publications

(11 citation statements)

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“…The opposite modes of homogenization of LV and VL fluids (LV→L and VL→V) within the same range of temperatures suggest that boiling of the ore fluid could have occurred during vein formation at Aliabad-Khanchy. Boiling is also consistent with the presence of colloform and chalcedonic quartz (e.g., White and Hedenquist, 1990;Hedenquist et al, 2000;Kouhestani et al, 2015Kouhestani et al, , 2017Mehrabi et al, 2016) within the ore zones. Deposition of chalcedonic quartz points to rapid deposition of SiO 2 , possibly due to the rapid cooling accompanying boiling, and caused by the loss of heat carried away by water vapor (e.g., Thiersch et al, 1997).…”

Section: Trapping Pressure and Mineralization Depthmentioning

confidence: 53%

“…Besides the Aliabad-Khanchy deposit, several other epithermal deposits of precious and base metal are found in the THMB (Fig. 1B) including Chodarchay (0.5 Mt averaging 0.9% Cu and 2 g/t Au; Yasami et al, 2017); Gulojeh (2.3 Mt averaging 3% Pb, 2.2% Zn, 1.5% Cu, 2.9 g/t Au, and 350 g/t Ag; Mehrabi et al, 2010Mehrabi et al, , 2016Ghasemi Siani et al, 2015); Khalyfehlou (60,000 tonnes averaging 8% Cu, 6 g/t Au, and 7 g/t Ag; Esmaeli et al, 2015;Hosseinzadeh et al, 2016), Lohneh (Rahmani, 2010;Zamanian et al, 2016), Rashtabad, Jalilabad and Aqkand (Feizi et al, 2016;Kouhestani et al, 2017), and the iron oxideapatite deposits at Sorkhe-Dizaj, Aliabad, Morvarid and Zaker (Nabatian and Ghaderi, 2013;Nabatian et al, 2013Nabatian et al, , 2014b. These deposits are controlled by normal faults and temporally and spatially associated with late Eocene magmatism.…”

Section: Introductionmentioning

confidence: 99%

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Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

Kouhestani

Mokhtari

Chang

2018

Ore Geology Reviews

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The Aliabad-Khanchy epithermal base metal deposit is located in the Tarom-Hashtjin metallogenic belt (THMB) of northwest Iran. The mineralization occurs as Cu-bearing brecciated quartz veins hosted by Eocene volcanic and volcaniclastic rocks of the Karaj Formation. Ore formation can be divided into five stages, with most ore minerals, such as pyrite and chalcopyrite being formed in the early stages. The main wall-rock alteration is silicification, and chlorite, argillic and propylitic alteration. Microthermometric measurements of fluid inclusion assemblages show that the ore-forming fluids have eutectic temperatures between −30° and −52°C, trapping temperatures of 150° to 290°C, and salinities of 6.6 to 12.4 wt.% NaCl equiv. These data demonstrate that the ore-forming fluids were medium-to high-temperature, medium-to low-salinity, and low-density H 2 O-NaCl-CaCl 2 fluids. Calculated δ 18 O values indicate that ore-forming hydrothermal fluids had δ 18 O water ranging from +3.6 to +0.8‰, confirming that the ore-fluid system evolved from dominantly magmatic to dominantly meteoric. The calculated 34 S H2S values range from-8.1 to-5.0‰, consistent with derivation of the sulfur from either magma or possibly from local volcanic wallrock. Combined, the fluid inclusion and stable isotope data indicate that the Aliabad-Khanchy deposit formed from magmatic-hydrothermal fluids. After rising to a depth of between 790 and 500 m, the fluid boiled and subsequent hydraulic fracturing may have led to inflow and/or mixing of early magmatic fluids with circulating groundwater causing deposition of base metals due to dilution and/or cooling. The Aliabad-Khanchy deposit is interpreted as an intermediate-sulfidation style of epithermal mineralization. 2 Our data suggest that the mineralization at Aliabad-Khanchy and other epithermal deposits of the THMB formed by hydrothermal activity related to shallow late Eocene magmatism. The altered Eocene volcanic and volcaniclastic rocks, especially at the intersection of subvolcanic stocks with faults were the most favorable sites for epithermal ore bodies in the THMB.

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Section: Trapping Pressure and Mineralization Depthmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

Kouhestani

Mokhtari

Chang

2018

Ore Geology Reviews

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“…THMP with 70-150 km wide and 300 km long hosts several epithermal Ag-Au and base-metal deposits including: low-sulfidation (Chargar, Nikuyeh), intermediate-sulfidation (Aqkand, Glojeh), and high-sulfidation (Chodarchay, Khalifehlu) deposits ( Figure 2; Table 1) [2,3,18,35,36]. Moreover, it hosts many iron oxide-apatite deposits (including Sorkheh-Dizaj, Aliabad, Morvarid and Zaker; [22,25,37].…”

Section: Regional Geologymentioning

confidence: 99%

“…Yasami et al [35] Kouhestani et al [18] Mehrabi et al [3] Hosseinzadeh et al [36] Aghajani et al [47] Zamanian et al [48] a HS: High-sulfidation, IS: Intermediate-sulfidation, LS: Low-sulfidation.…”

Section: Referencementioning

confidence: 99%

“…The northwestern part of the AAMB includes two mineralized subzones named the Ahar-Arasbaran Belt (AAB) in the north and the Tarom-Hashjin metallogenic province (THMP) in the south (Figure 1) [2,3]. The THMP is known as an economically important metallogenic province in Iran [2,14,15] and includes a variety of mineral deposits such as Mn deposits, iron-skarns, manto-type Cu-Ag deposits, and Zn-Pb-Cu±Au-Ag epithermal deposits [3,[16][17][18][19]. All of these deposits are variably attributed to post-collisional magmatic processes (e.g., [20][21][22]).…”

Section: Introductionmentioning

confidence: 99%

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The Shah-Ali-Beiglou Zn-Pb-Cu (-Ag) Deposit, Iran: An Example of Intermediate Sulfidation Epithermal Type Mineralization

et al. 2018

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The Shah-Ali-Beiglou epithermal base metal-silver deposit is located in the Tarom-Hashjin metallogenic province (THMP) in northwestern Iran. This deposit is hosted by quartz monzonite dikes of Oligocene age and surrounded by andesite to trachyandesite volcanic and volcaniclastic rocks of Eocene age. The subvolcanic rocks in the study area vary in composition from quartz-monzonite to monzonite and have metaluminous, calc-alkaline to shoshonitic affinity. These rocks have I-type geochemical characteristic and are related to post-collisional tectonic setting. The mineralization occurs as NE-SW and E-W-trending brecciated veins controlled by strike-slip and normal faults, which are associated to the Late Oligocene compressional regime. The mineral paragenesis of the vein mineralization is subdivided into pre-ore stage, ore stage, post-ore stage, and supergene stage. Pre-ore stage is dominated by quartz, sericite, and subhedral to anhedral pyrite as disseminated form. Ore-stage is represented by quartz, sphalerite (from 0.1 mol % to 4 mol % FeS), galena, chalcopyrite, tetrahedrite-tennantite, minor seligmannite and enargite, as vein-veinlet, cement and clast breccias. Post-ore stage is defined by deposition of quartz and carbonate along with minor barite, and supergene stage is characterized by bornite, chalcocite, covellite, hematite, goethite, and jarosite. The ore mineralization is associated with the silicic alteration. The styles of alteration are silicic, carbonate, sericitic, chloritic, and propylitic. Fluid inclusions in sphalerite have a wide range of salinities between 0.35 wt % and 21.4 wt % NaCl equivalent and homogenization temperatures range from 123 to 320 • C. The isotopic values of sulfides vary from 2.8 to 6.7 suggesting a magmatic source for the sulfur. In the present study, based on geological setting, alteration style of the host and wall rocks, main textures, mineral assemblages, composition of ore minerals, and structural features, it is suggested that the mineralization in the Shah-Ali-Beiglou is similar to intermediate-sulfidation style of epithermal deposits.

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Geochemical constraints on the origin and tectonic setting of Chargar intrusions in the Alborz orogenic belt, NW Iran

et al. 2019

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Chargar area is located in the southern border of Tarom subzone within the Alborz magmatic belt of NW Iran. Two types of intrusions, mainly present in the southern part of the area, have been identified. These bodies intruded into the Karaj Formation volcanic and volcaniclastic rocks. Type-I intrusions occur in the south and include two magmatic bodies: (a) Gabbro-pyroxene quartz monzodiorite-quartz monzodiorite and (b) quartz syenite. Type-II crops out in the west and has a gabbrogabbro-diorite composition. Geochemically, Chargar intrusive rocks belong to the high-K calc-alkaline to shoshonitic series and are classified as I-type and metaluminous granitoids. These intrusive rocks show insignificant different distribution patterns of trace elements and REEs, but generally they are characterized by highly enriched large ion lithophile elements (e.g., K and Ba) and depleted Nb, similar to that of continental arc magmatism. Type-I intrusions and Type-II mafic intrusion were originated from mantle source with amphibole-bearing spinel peridotite composition. These intrusions formed in a continental arc to post-collisional tectonic setting.

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Mineralization and fluid evolution of epithermal base metal veins from the Aqkand deposit, NW Iran

Cited by 16 publications

References 0 publications

Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

Intermediate sulfidation type base metal mineralization at Aliabad-Khanchy, Tarom-Hashtjin metallogenic belt, NW Iran

The Shah-Ali-Beiglou Zn-Pb-Cu (-Ag) Deposit, Iran: An Example of Intermediate Sulfidation Epithermal Type Mineralization

Geochemical constraints on the origin and tectonic setting of Chargar intrusions in the Alborz orogenic belt, NW Iran

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