| 大兴安岭南段维拉斯托锡多金属矿床流体包裹体和同位素特征 |
| Received:December 25, 2016 Revised:February 28, 2018 点此下载全文 |
| 引用本文：LIU RuiLin,WU Guang,CHENG GongZheng,LI TieGang,JIANG Biao,WU LiWen,ZHANG PeiChun,ZHANG Tong,CHEN YuChuan.2018.Characteristics of fluid inclusions and H-O-C-S-Pb isotopes of Weilasituo Sn-polymetallic deposit in southern Da Hinggan Mountains[J].Mineral Deposits,37(2):199~224 |
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| Author Name | Affiliation | E-mail | | LIU RuiLin | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
Key Laboratory of Orogen and Crust Evolution, Ministry of Education, Peking University, Beijing 100871, China | | | WU Guang | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China | wuguang65@163.com | | CHENG GongZheng | School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China | | | LI TieGang | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China | | | JIANG Biao | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China | | | WU LiWen | Inner Mongo-lia Institute of Geological Survey, Hohhot 010020, Inner Mongolia, China | | | ZHANG PeiChun | Inner Mongo-lia Institute of Geological Survey, Hohhot 010020, Inner Mongolia, China | | | ZHANG Tong | Inner Mongo-lia Institute of Geological Survey, Hohhot 010020, Inner Mongolia, China | | | CHEN YuChuan | Chinese Academy of Geological Sciences, Beijing 100037, China | |
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| 基金项目:国家重点研发计划项目（编号：2017YFC0601303）、内蒙古自治区地质勘查基金项目（编号：2015-01-YS01）和国家自然科学基金项目（编号：41772086）的资助 |
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| 中文摘要:维拉斯托锡多金属矿床位于大兴安岭南段西坡，是一个以锡为主，共伴生锌、钨、铜、钼、铷、铌、钽和锂的大型矿床。矿床包括深部以锡为主，伴生锌、铷、铌和钽的蚀变花岗岩型矿体；中部以锂为主，伴生锡、锌、铜和铷的隐爆角砾岩型矿体及浅部锡、钨、锌、铜和钼的石英大脉型和网脉型矿体。矿床的主要工业矿体为石英脉型，呈北北东向产于古元古界宝音图群和华力西中期石英闪长岩中的断裂破碎带内，而蚀变花岗岩型和隐爆角砾岩型矿石的品位较低。矿床的成矿过程可以划分为4个阶段：钠长石化-天河石化阶段（Ⅰ）、云英岩化阶段（Ⅱ）、锡钨氧化物-多金属硫化物阶段（Ⅲ）和钼多金属硫化物阶段（Ⅳ）。为了查明成矿流体性质、成矿流体和成矿物质来源及矿质沉淀机制，文章对Ⅰ、Ⅲ和Ⅳ阶段的脉石英开展了流体包裹体研究和H-O-C同位素分析，对硫化物开展了S-Pb同位素分析。维拉斯托锌多金属矿床发育富液两相（WL型）、富气两相（WG型）、H2O-CO2（C型）和含子矿物多相（S型）4种类型的包裹体。Ⅰ阶段发育WL型、WG型和S型包裹体，均一温度372~473℃，盐度w（NaCleq）5.3%~50.9%；Ⅲ阶段亦发育WL型、WG型和S型包裹体，均一温度243~412℃，盐w（NaCleq）为4.3%~48.5%；Ⅳ阶段发育WL型、WG型、C型和S型包裹体，均一温度215~414℃，盐度w（NaCleq）4.1%~48.5%。矿床的δ18OH2O值介于2.4‰~8.5‰之间，δD值介于-120‰~-79‰之间，δ13CV-PBD值为-15.5‰~-14.9‰，表明成矿流体以岩浆水为主，后期有少量大气降水的加入。矿石的δ34S值为-4.6‰~-2.2‰；矿石的206Pb/204Pb、207Pb/204Pb和208Pb/204Pb比值分别为18.310~18.381、15.531~15.584和38.151~38.326。S-Pb同位素组成表明成矿物质主要来源于岩浆。维拉斯托锡多金属矿床属于岩浆-中高温热液矿床，成矿与早白垩世的斑状细粒碱长花岗岩有关。流体沸腾和降温是矿质沉淀的主要机制。 |
| 中文关键词:地球化学 流体包裹体 H-O-C-S-Pb同位素 锡多金属矿床 维拉斯托 大兴安岭南段 |
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| Characteristics of fluid inclusions and H-O-C-S-Pb isotopes of Weilasituo Sn-polymetallic deposit in southern Da Hinggan Mountains |
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| Abstract:The Weilasituo Sn-polymetallic deposit, located on the west slope of the southern Da Hinggan Mountains, is a large-sized tin (Sn) deposit associated with zinc (Zn), tungsten (W), copper (Cu), molybdenum (Mo), rubidium (Rb), niobium (Nb), tantalum (Ta), and lithium (Li). Three types of mineralization are developed in the deposit, i.e., the altered granite-type orebody dominated by Sn and associated Zn, Rb, Nb, and Ta in the depth, the cryptoexplosive breccia-type orebody dominated by Li with Sn, Zn, Cu and Rb in the middle depth, and the quartz vein-type Sn, W, Zn, Cu, and Mo orebody in the shallow part. Of them, the quartz vein-type orebodies have the most economically value and are hosted within NNE-trending faulted and shattered zones which occur in the Paleoproterozoic Baoyintu Group and the Middle Variscan quartz diorite, while the ore grade of the altered granite-and cryptoexplosive breccia-type orebodies is usually low. The ore-forming process of the deposit can be divided into four stages, i.e. albitization-amazonitization stage (Ⅰ), greisenization stage (Ⅱ), Sn-W oxide-polymetallic sulfide stage (Ⅲ), and Mo-polymetallic sulfide stage (Ⅳ). In order to find out the properties of the ore fluids, source of ore fluids and ore-forming materials as well as mineral precipitation mechanism of the deposit, the authors carried out fluid inclusion study and H-O-C isotopic analysis for quartz veins and S-Pb isotopic analysis for sulfides from stages I, Ⅲ, and IV of the deposit. Four types of fuid inclusions have been distinguished in various quartz veins, i.e., liquid-rich (WL type), gas-rich (WG type), H2O-CO2 (C type), and daughter mineral-bearing inclusions (S type). The fuid inclusions in the stage I contain WL-, WG-, and S-types, and their homogenization temperatures and salinities w(NaCleq) vary from 372℃ to 473℃ and 5.3% to 50.9%, respectively, whereas the fuid inclusions in the stage Ⅲ contain also WL-, WG-, and S-types, and their homogenization temperatures and salinities vary from 243℃ to 412℃ and 4.3% to 48.5% NaCleqv, respectively. In addition, the fluid inclusions in the stage IV contain WL-, WG-, C-, and S-types, and their homogenization temperatures and salinities vary from 215℃ to 414℃ and 4.1 to 48.5% w(NaCleq), respectively. The δ18OH2O and δDH2O values of ore-forming fluids vary from 2.4‰ to 8.5‰ and -120‰ to -79‰, respectively, indicating that the ore-forming fluids mainly originated from the magma. The δ13C value varies from -15.5‰ to -14.9‰, which is consistent with the δ13C value of evolutional granitic magma, implying that the ore-forming fluids mainly originated from magma with minor atmospheric water. The δ34S values of metallic sulfides from ore range from -4.6‰ to -2.2‰. The 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, values of metallic sulfides vary from 18.310 to 18.381, 15.531 to 15.584, and 38.151 to 38.326, respectively. Both S and Pb isotopes indicate that the ore-forming materials of the Weilasituo deposit chiefly originated from the granitic magma. The Weilasituo Sn-polymetallic deposit belongs to a magmatic medium-to-high temperature hydrothermal deposit, and its mineralization was closely related to the Early Cretaceous porphyritic fine-grained alkali-feldspar granite in the Weilasituo ore district. The boiling and cooling of the ore fluids seem to have been the dominant mechanism for mineral precipitation. |
| keywords:geochemistry fluid inclusions H-O-C-S-Pb isotopes tin-polymetallic deposit Weilasituo southern Da Hinggan Mountains |
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