| 四川省石棉县大水沟碲矿床地质,矿物学和地球化学 |
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| 引用本文：毛景文,陈毓川,周剑雄,杨百川.1995.四川省石棉县大水沟碲矿床地质,矿物学和地球化学[J].地球学报,16(3):276-290. |
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| 中文摘要:位于杨子地台西缘的大水沟碲矿床是世界迄今唯一一例独立碲矿床。成矿围岩为一层30一50 ｍ厚的三叠纪变基性火山岩及厚层状大理岩。矿体呈脉状平行排列，走向ＮＮＥ。成矿作用可以分为磁黄铁矿黄铁矿阶段、辉碲铋矿阶段和黄铜矿黄铁矿（自然金）阶段，其中第二阶段是主要碲矿化阶段。该阶段矿石的碲品位一般为0.2％一５％，富矿石达15％一25％。在矿脉两侧围岩蚀变十分发育，于磁黄铁矿黄铁矿阶段矿脉和辉碲铋矿阶段矿脉两侧分别形成以黑云母为主和以白云母为主的两套蚀变组合及分带。岩石地球化学研究表明，从矿脉边侧向外，Ｋ、Ｎａ和Ｃａ组分降低，Ｆｅ和Ｍｇ组分增高。矿脉中白云母的K-Ar年龄测定为149.86±2.72Ｍａ。黄铁矿的Ｃｏ／Ｎｉ比值为56-652。成因矿物学和地球化学特征反映出大水沟碲矿床的成矿物质来自深源，其成矿作用可能与区域上燕山期碱性岩浆或碱质花岗岩活动有关。成矿时磁黄铁矿黄铁矿阶段的硫逸度（fｓ２）为１０￣（－１６．７），碲逸度（ｆＴｅ＿２）为１０￣（－１５）一１０￣（－１４）；辉碲铋矿阶段的ｆｓ＿２１０￣（－１４）一１０￣（－１１．５）和ｆＴｅ＿２１０￣（－１１．２）一１０￣（－１０．５）。 |
| 中文关键词:碲矿床 矿物学 地球化学 四川省 石棉县 |
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| Geology, Mineralogy, and Geochemistry of the Dashuigou Tellurium Deposit in Shimian County, Sichuan |
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| Abstract:To date Dashuigou tellurium deposit, located on the west margin of Yangtze platform, is, thesole example of tellurium- dominated deposit in the world. The host rock for the mineralization is alayer of Triassic metamafic rock 30m to 50m thick. Thirteen ore veins, which strike 0°to 10° anddip 270° to 280° of angles of 60° to 70°,have been discovered in the deposit. These veins are general-ly about one hundred to several hundred meters long, dosens of centimenters thick, and severaldozen to more than one hundred meters deep; Tellurium mineralizations in the deposit can be divid-ed into three stages,i.e, pyrrhotite-pyrite stage, tetradymite stage, and pyrite-chalcopyrite(nativegold)stage, The tetradymite stage is the most important of them in reserve of tellurium, and it com-pries several species of tellurium-bearing minerals, such as, tetradymite , tsumoite, tellurbisrnuth,jodeite, stuetzite,native tellurium, wehrlite, and calaverrte. The tellurium grades of the ores gen-erally range from 0.2%to 5%,and are 15%一25% for the rich ores; Gangue minerals in the oresare dolomite biotite,muscovite,albite, quartz, chlortz and calcite, Wall rock alteralions around theore veins intensively develop and usually exhibit zoningS in space. The alteration zones around thepyrrhotite- pyrite ore veins include coarse-grained biotite zone, fine- grained quartz-albite- biotitezone, quartz-biotite-actinolite zone to chlorite-amphibole zone. The alteration zones around the te-tradymite ore veins are fine-grained hematite-calcite-muscovite zone, quartz-calcite-chlorite-action-lite zone,and chlorite-amphibele zone. K, Na and Ca decrease, and Fe and Mg increas from the oreveins outward. A K-Ar agr of 149. 86±2. 72 Ma has been measured from seperated muscovite inthe ore veins. Genetic mineralogy and geochemistry indicate that the tellurium mineralizations in theDashuigou deposit is possibly related to the buried alkaline granite or syenite-leucitite intrusions 14O-80 Ma in age, which occur in surrounding areas of the deposit. Sulfur fugacity(fs_2)and telluriumfugacity(fTe_2)are 10￣(-16.7) and 10￣(-15)一10￣(-14_) respoctively. during the pyrrhotite-pyrite stage, and10￣(-14)一10￣(-11) and 10￣(11.2)一10￣(-10.5) for the tetradymite stage. |
| keywords:tellurium deposit geology mineralogy geochemistry Shimian Sichuan |
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