Abstract Siah Jangal-Sar Kahno deposit is located in the northern part of Taftan volcano in the Sistan and Balouchestan provinces, southeast of Iran, and is an example of a vein-type epithermal gold system with related stockwork and shear zone mineralization. The veins are hosted by flysch facies rocks of the Makran zone and subvolcanic dioritic porphyry. The NE-SW fault systems played an essential role in the genesis of alteration and mineralization in the area. Diorite porphyry ranges from alkali (Na2O+K2O) content of 4.1–6.66 wt.%, and plot in the calc-alkaline to high-K calc-alkaline fields. The chondrite-normalized REE patterns for least altered porphyry diorite rocks, altered host rocks, and silica-carbonate vein show a LREE/HREE ratios of 10.40, 4.03, 4.00, and 2.66, respectively. Positive Eu anomalies in the silica-carbonate veins indicate the Ca-bearing minerals, such as plagioclase decomposition causing release of Eu into hydrothermal fluid and subsequent precipitation in silica-carbonate veins. Mineralization consist of quartz, adularia, calcite, pyrite, arsenopyrite, marcasite, Fe-poor sphalerite, galena, chalcopyrite, and native gold. Later supergene mineral assemblages consists of Fe-oxide and hydroxides, covellite, cerussite, and scorodite. Hydrothermal alteration is generally well developed enveloping the ore-bearing hydrothermal breccia and subdivided into prograde inner quartz-chlorite-pyrite-muscovite, and outer argillic alteration zones, with a regional barren, widespread near-surface supergene (blanket) advanced argillic alteration zone. Chemical discrimination by means of cationic R1-R2 diagram indicates that R1 increases, whereas R2 decreases with increasing argillic alteration. Microthermometry of fluid inclusions in quartz crystals from silica-carbonate vein show the homogenization temperatures (Thv-l) of 167°–332 °C with salinities in the range of 0.21 to 4.24 wt.% NaCl eq. The O and H isotopic compositions of quartz from hydrothermal vein and argillic alteration simply show a low sulfidation epithermal environment with meteoric waters as the main fluid. Due to a narrow range in salinity of the fluids, very low sulfide diversity, sulfide volume, and presence of adularia suggest dominantly meteoric water in the deposit, supporting classification as a low-sulfidation epithermal system.

中文翻译：

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伊朗东南部 Siah Jangal-Sar Kahno 浅成热液金矿床的矿物学、热液蚀变、流体包裹体和 OH 稳定同位素

摘要 Siah Jangal-Sar Kahno 矿床位于伊朗东南部锡斯坦省和俾路支省的塔夫坦火山北部，是具有相关网状和剪切带矿化作用的脉状浅成热液金系统实例。这些脉由 Makran 带的复理石相岩石和次火山闪长斑岩组成。NE-SW 断层系统在该地区蚀变和成矿的成因中发挥了重要作用。闪长岩斑岩的碱 (Na2O+K2O) 含量范围为 4.1–6.66 wt.%，并在钙碱性到高钾钙碱性场中绘制。最小蚀变斑岩闪长岩、蚀变母岩和硅碳酸盐脉的球粒陨石归一化 REE 模式显示 LREE/HREE 比率分别为 10.40、4.03、4.00 和 2.66。硅碳酸盐脉中的正 Eu 异常表明含钙矿物，例如斜长石分解导致 Eu 释放到热液中，随后在硅碳酸盐脉中沉淀。矿化包括石英、冰晶、方解石、黄铁矿、毒砂、白铁矿、贫铁闪锌矿、方铅矿、黄铜矿和原生金。后来的表生矿物组合由铁氧化物和氢氧化物、铜钴矿、铜辉石和臭葱石组成。热液蚀变普遍发育良好，包覆含矿热液角砾岩，并细分为内层石英-绿泥石-黄铁矿-白云母前级和外层泥质蚀变带，具有区域性贫瘠、广泛的近地表表生（毯状）晚期泥质蚀变带。通过阳离子R1-R2图的化学区分表明R1增加，而R2随着泥质改变的增加而减少。来自二氧化硅-碳酸盐脉的石英晶体中流体包裹体的显微温度测量显示均质温度 (Thv-l) 为 167°–332 °C，盐度范围为 0.21 至 4.24 wt.% NaCl eq。来自热液脉和泥质蚀变的石英的 O 和 H 同位素组成简单地显示出以大气水为主要流体的低硫化超热环境。由于流体的盐度范围很窄，硫化物多样性、硫化物体积非常低，并且存在泥炭表明矿床中主要是大气水，支持将其归类为低硫化超热液系统。来自二氧化硅-碳酸盐脉的石英晶体中流体包裹体的显微温度测量显示均质温度 (Thv-l) 为 167°–332 °C，盐度范围为 0.21 至 4.24 wt.% NaCl eq。来自热液脉和泥质蚀变的石英的 O 和 H 同位素组成简单地显示出以大气水为主要流体的低硫化超热环境。由于流体的盐度范围很窄，硫化物多样性、硫化物体积非常低，并且存在泥炭表明矿床中主要是大气水，支持将其归类为低硫化超热液系统。来自二氧化硅-碳酸盐脉的石英晶体中流体包裹体的显微温度测量显示均质温度 (Thv-l) 为 167°–332 °C，盐度范围为 0.21 至 4.24 wt.% NaCl eq。来自热液脉和泥质蚀变的石英的 O 和 H 同位素组成简单地显示出以大气水为主要流体的低硫化超热环境。由于流体的盐度范围很窄，硫化物多样性、硫化物体积非常低，并且存在泥炭表明矿床中主要是大气水，支持将其归类为低硫化超热液系统。来自热液脉和泥质蚀变的石英的 O 和 H 同位素组成简单地显示出以大气水为主要流体的低硫化超热环境。由于流体的盐度范围很窄，硫化物多样性、硫化物体积非常低，并且存在泥炭表明矿床中主要是大气水，支持将其归类为低硫化超热液系统。来自热液脉和泥质蚀变的石英的 O 和 H 同位素组成简单地显示出以大气水为主要流体的低硫化超热环境。由于流体的盐度范围很窄，硫化物多样性、硫化物体积非常低，并且存在泥炭表明矿床中主要是大气水，支持将其归类为低硫化超热液系统。