| 甘肃枣子沟金矿床成矿过程分析——来自矿床地质特征、金的赋存状态及稳定同位素证据 |
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| 引用本文： | 曹晓峰,Mohamed Lamine Salifou Sanogo,吕新彪,何谋春,陈超,朱江,唐然坤,刘智,张彬.甘肃枣子沟金矿床成矿过程分析——来自矿床地质特征、金的赋存状态及稳定同位素证据[J].吉林大学学报(地球科学版),2012(4):1039-1054. |
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| 作者姓名： | 曹晓峰 Mohamed Lamine Salifou Sanogo 吕新彪 何谋春 陈超 朱江 唐然坤 刘智 张彬 |
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| 作者单位： | 中国地质大学资源学院;中国地质大学地质过程与矿产资源国家重点实验室;北京矿通资源开发咨询有限责任公司 |
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| 基金项目： | 国家科技支撑计划项目(2011BAB06B04);中国地质大学地质过程与矿产资源国家重点实验室基金项目(124-G08Y60104) |
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| 摘 要： | 枣子沟金矿位于同仁-夏河-岷县金成矿带,矿区赋矿地层为三叠纪中统古浪堤组下段细碎屑岩及灰岩,并发育大量闪长质脉岩。矿体既产于地层中,也出现在脉岩或其接触带中,但其产状均严格受NE、NW及近SN向3组断裂构造控制,控矿构造为高角度的张剪性及旋扭性断裂。热液成矿期可划分为黄铁矿-石英阶段,黄铁矿-毒砂-(闪锌矿-方铅矿-黄铜矿-辉银矿-绢云母-绿泥石-)石英阶段,辉锑矿-石英-方解石阶段及石英-方解石阶段。围岩蚀变类型主要为硅化、方解石化及绢云母化。环境扫面电镜及电子探针测试数据表明,金呈显微可见金存在于矿物裂隙和粒间隙中或以纳米不可见金捕获在载金矿物中。成矿期不同硫化物金的质量分数均高出检测限,其范围为0.003%～0.658%,平均值为0.257%。枣子沟金矿床具有卡林型金矿床的典型特征。氢氧同位素数据显示成矿流体主要来自大气水,硫同位素数据则表明硫主要来自沉积地层。其成矿过程可能为深切割断裂导通地下水,在深部被加热循环萃取围岩中成矿物质,并在浅表张性断裂中充填交代围岩,致使成矿物质沉淀富集成矿。金的迁移形式可能存在AuH3SiO04、Au(HS)2-、H2Au(Sb,As)S02和HAu(Sb,As)S3-等多种迁移方式。成矿早阶段可能以金硅络合物的解体为主,成矿晚阶段则可能是硫氢(锑)络合物发生解体,致使金与硫化物同时沉淀,以显微纳米金的形式包含在硫化物中。
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| 关 键 词： | 枣子沟 微细浸染型 金矿 成矿期 稳定同位素 金的赋存状态 |
Ore-Forming Process of the Zaozigou Gold Deposit: Constraints from Geological Characteristics, Gold Occurrence and Stable Isotope Compositions |
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| Cao Xiao-feng,Mohamed Lamine Salifou Sanogo,Lü Xin-biao,He Mou-chun,Chen Chao,Zhu Jiang,Tang Ran-kun,Liu Zhi,Zhang Bin.Ore-Forming Process of the Zaozigou Gold Deposit: Constraints from Geological Characteristics, Gold Occurrence and Stable Isotope Compositions[J].Journal of Jilin Unviersity:Earth Science Edition,2012(4):1039-1054. |
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| Authors: | Cao Xiao-feng Mohamed Lamine Salifou Sanogo Lü Xin-biao He Mou-chun Chen Chao Zhu Jiang Tang Ran-kun Liu Zhi Zhang Bin |
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| Institution: | 1.Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China 2.State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China 3.Beijing Kuangtong Resource Development Consulting Company Ltd.,Beijing 100037,China |
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| Abstract: | The Zaozigou gold deposit is located in the Tongren-Xiahe-Minxian gold metallogneic belt in west Qinling orogen.The ore bodies are hosted in fine-grained clastic rocks intercalated with limestone of the Middle-Triassic Gulangti Formation and varied dikes.The gold ore bodies are strictly controlled by the NE,NW and SN trending tensional and shearing faults with high dipping angle.The ore-forming hydrothermal period is divided into four stages: pyrite-quartz,pyrite-arsenopyrite quartz,stibnite-quartz-calcite and quartz-calcite.Quartz,calcite and sericite are the main alteration minerals.Environmental scanning electron microscope and electron probe analyses show that the gold is micro-visible or invisible.Micro-visible gold is seen in the intercrystalline space or in the fissures of quartz and silicates.Invisible gold is captured in pyrite,arsenopyrite,stibnite and other sulfide mainly as nanoparticles.Gold concentration in sulphides of ore-forming stages is between 0.003% and 0.658% with an average of 0.257%.All the characteristics above lead us to draw the conclusion that the Zaozigou deposit is a typical carlin-type.Hydrogen and oxygen isotope compositions show that ore-forming fluids came from meteoric water while sulfur isotope compositions show that the sulfur came from the sedimentary strata.The meteoric water went deep into the crust through the deep cutting faults and was heated and circulated to extract the metals from the wall rocks.Gold may be transported in the hydrothermal fluids in forms of AuH3SiO04、Au(HS)-2,H2Au(Sb,As)S02 and HAu(Sb,As)S-3.In the early stage,the breakup of the AuH3SiO04 complex resulted in the deposition of Au and Si,Fe,Na,Al etc;while in the later stages the breakup of Au(HS)-2,H2Au(Sb,As)S02 and HAu(Sb,As)S-3 complexes led to the simultaneous deposition of sulfides and gold nanoparticles in them. |
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| Keywords: | Zaozigou micro-disseminated gold deposits ore-forming period stable isotopes gold occurrence |
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