| 西藏冈底斯中段恰功多金属矿床成矿流体性质与演化 |
| |
| 引用本文： | 李应栩,李光明,谢玉玲,张丽,刘保顺,李腊梅.西藏冈底斯中段恰功多金属矿床成矿流体性质与演化[J].地球科学,2018,43(8):2684-2700. |
| |
| 作者姓名： | 李应栩 李光明 谢玉玲 张丽 刘保顺 李腊梅 |
| |
| 作者单位： | 1.中国地质调查局成都地质调查中心, 四川成都 610081 |
| |
| 基金项目： | 国家重点研发计划项目2016YFC0600308国家自然科学基金项目41702086中国地质调查局项目DD20160015 |
| |
| 摘 要： | 目前对于中冈底斯成矿带上的矿床的研究主要在地质特征、成矿时代和成矿岩体成因方面，而对于其形成过程尤其是成矿流体演化方面的详细研究报道较少.该成矿带上的恰功多金属矿床代表了主碰撞期的成矿作用，其矿化形式包括矽卡岩型的铁（铜）、热液脉型铅锌银（铜）和碳酸盐交代型铅锌银3种.通过野外地质调查和镜下岩矿相观察，可将该矿床的形成过程划分为（Ⅰ）石榴石-磁铁矿复合阶段、（Ⅱ）绿帘石-磁铁矿阶段、（Ⅲ）石英-赤铁矿阶段、（Ⅳ）萤石-黄铜矿阶段、（Ⅴ）方解石-方铅矿-闪锌矿阶段和（Ⅵ）方解石-石英6个成矿阶段.对代表成矿各阶段的流体包裹体进行了岩相学、显微测温、显微激光拉曼、质子激发X荧光光谱分析等，结果显示成矿流体从早期到晚期温度、压力、密度和盐度不断降低，兼有渐变和突变，流体相主要成分由早期H2O-NaCl（Ⅰ-Ⅱ）经中期H2O-NaCl-FeCl2-3±MgCl2（Ⅲ）和H2O-CO2-NaCl（Ⅳ）向晚期H2O-NaCl-CaCl2（Ⅴ&Ⅵ）变化.期间铜的沉淀主要与Ⅳ阶段流体沸腾有关，铅锌的沉淀可能与Ⅴ阶段温度降低有关，也可能为叠加矿化的结果.
|
| 关 键 词： | 恰功多金属矿床 流体包裹体 成矿流体 斑岩 矽卡岩型 热液型 矿床学 |
| 收稿时间： | 2018-03-06 |
Properties and Evolution Path of Ore-Forming Fluid in Qiagong Polymetallic Deposit of Middle Gangdese in Tibet,China |
| |
| Abstract: | The current study of the deposits on the Middle Gangdese metallogenic belt is mainly related to geological features, metallogenic epochs and the origin of ore-forming rock masses.However, there are less detailed reports on the formation process, especially the evolution of ore-forming fluids.Qiagong polymetallic deposit located in the belt is genetically related to monzogranite porphyry formed at early India-Asia continental collision.The mineralization styles include skarn type Fe(-Cu), distal vein type Pb-Zn-Ag(-Cu) and carbonate replacement type Pb-Zn-Ag.Based on field observation and petrographic results the ore-forming process in this deposit can be divided into at least six stages including complexed garnet-magnetite stage (Ⅰ), epidote-magnetite stage (Ⅱ), quartz-hematite stage (Ⅲ), fluorite-chalcopyrite stage (Ⅳ), calcite-galena-sphalerite stage (Ⅴ) and calcite-quartz stage (Ⅵ).Petrographic, microthermometric and laser Raman microprobe results of fluid inclusions in quartz, garnet, epidote, calcite and fluorite from these six stages demonstrate that the pressure, temperature, density and salinity of the ore forming fluid decrease from early to later stage, and the fluid system change from early H2O-NaCl (Ⅰ-Ⅱ) via H2O-NaCl-FeCl2-3±MgCl2(Ⅲ), H2O-CO2-NaCl (Ⅳ) to late H2O-NaCl-CaCl2(Ⅴ & Ⅵ).The deposition of Cu in Qiagong was triggered by the boiling of the ore-forming fluid of H2O-CO2-NaCl system from stage Ⅳ.The deposition of Pb and Zn might be ascribed to the temperature decrease, or it might also be the result of mineralization superposition. |
| |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
|
点击此处可从《地球科学》下载全文 |
|
