| 云南个旧卡房矿田锡-铜矿床成矿作用过程探讨:成矿流体约束 |
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| 引用本文： | 张娟,毛景文,程彦博,李肖龙.云南个旧卡房矿田锡-铜矿床成矿作用过程探讨:成矿流体约束[J].岩石学报,2012,28(1):166-182. |
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| 作者姓名： | 张娟 毛景文 程彦博 李肖龙 |
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| 作者单位： | 1. 中国地质大学地球科学与资源学院,北京,100083
2. 中国地质大学地球科学与资源学院,北京100083;中国地质科学院矿产资源研究所,北京100037 |
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| 基金项目： | 本文受国家自然科学基金重点项目(40930419)、国土资源部公益性行业科研专项(200911007-12)、云南锡业集团有限责任公司科研项目(2010-04A)和国家973项目(1212011120994)联合资助. |
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| 摘 要： | 云南个旧是世界上最大的锡多金属矿区,卡房矿田是其中一个主要的铜矿区。卡房铜矿主要的矿床类型有:变玄武岩型层状铜矿和接触带型铜矿,本文主要对前者进行了流体包裹体测试及同位素地球化学分析,并对比研究了接触带型铜矿的同位素地球化学特征。流体包裹体研究显示,卡房矿田变玄武岩型层状铜矿的成矿流体,属于岩浆流体体系演化的一部分,成矿作用分为三个阶段:石英-磁黄铁矿-黄铜矿阶段(Ⅰ)、石英-方解石-黄铜矿-黄铁矿阶段(Ⅱa)和石英-方解石阶段(Ⅱb)。从Ⅰ-Ⅱa-Ⅱb成矿流体的温度(平均从363.9℃至283.2℃至185.0℃)显著降低,流体盐度(平均从20.18% NaCleqv至12.59% NaCleqv至11.97% NaCleqv)缓慢降低,流体密度(平均从0.854g/cm3至0.863g/cm3至1.001g/cm3)基本不变。显微激光拉曼光谱分析显示流体包裹体的挥发份主要为H2O及少量CH4,液相中主要成分为H2O及少量CO2-3。氢、氧同位素研究(δDH2O值介于-98‰~-79‰;δ18OH2O值介于-0.82‰~7.09‰)显示,成矿流体主要以岩浆水为主,在成矿流体上升过程中与地层中的大气降水相混合。硫同位素分析结果表明,卡房矿田变玄武岩型铜矿中硫化物的硫(δ34S值介于-0.86‰~3.8‰)来源于三叠纪变玄武岩,而花岗岩浆和变玄武岩共同为卡房接触带型铜矿(δ34S值介于-3.2‰~6.2‰)提供了成矿所需的大部分硫。
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| 关 键 词： | 流体包裹体 同位素地球化学 岩浆热液 个旧卡房铜矿 |
| 收稿时间： | 2011/7/18 0:00:00 |
| 修稿时间： | 2011/10/26 0:00:00 |
Mineralization process of the Kafang tin-copper deposit in the Gejiu district, Yunnan Province: Constraints from fluid inclusion |
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| ZHANG Juan,MAO JingWen,CHENG YanBo and LI XiaoLong.Mineralization process of the Kafang tin-copper deposit in the Gejiu district, Yunnan Province: Constraints from fluid inclusion[J].Acta Petrologica Sinica,2012,28(1):166-182. |
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| Authors: | ZHANG Juan MAO JingWen CHENG YanBo and LI XiaoLong |
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| Institution: | School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China; Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | The Gejiu polymetallic tin ore district,located in Yunnan Province,is the largest tin deposit over the world.The Kafang copper(tin)deposit is one component of it,characterized by enriched copper.There are two main kinds of ore-body in Kafang copper deposit.One is stratiform-like ore-body,and the other is contact ore-body.In this paper we carried out fluid inclusion study and isotope geochemistry analysis of the former kind ore-body,as well as the latter kind with isotope geochemistry analysis.The mineralization in the deposit can be divided into three stages,i.e.quartz-pyrrhotite-chalcopyrite stage(Ⅰ),quartz-calcite-chalcopyrite-pyrite stage(Ⅱa)and quartz-calcite stage(Ⅱb).The ore-forming fluids of the three stages physical-chemically changed from moderate-high temperature(363.9℃in average),moderate salinity(20.1 8%NaCleqv in average)and low density(0.854g/ cm3in average)via moderate temperature(283.2℃in average),moderate-low salinity(1 2.59%NaCleqv in average)and low density(0.863 g/cm3 in average)to low temperature(1 85.0℃in average),low salinity(1 1.97%NaCleqv in average)and low density(1.001 g/cm3 in average).The Laser Raman data of the ore-forming fluid inclusions shows that it is rich of H 2 O,CH 4 in gas phase,and H 2 O,CO 3 2- in liquid phase.Hydrogen isotope analysis and oxygen isotope analysis(δD H2O lies between-98‰～-79‰;δ18 O H2O lies between-0.82‰～7.09‰)show that the ore-forming fluid dominated by magmatic water in the early stage, but in late stage,it could be produced by mixing magmatic and meteoric water.The compositions of sulfur isotope show that sulfur of stratiform-like ore-body(δ34 S lies between-0.86‰～3.8‰)was derived from Triassic basalt lava.Both Triassic basalt lava and Yanshanian granite provide sulfur for the ore-forming process(δ34 S lies between-3.2‰～6.2‰). |
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| Keywords: | Fluid inclusion Isotope geochemistry Granitic hydrothermal fluid Kafang copper deposit in Gejiu |
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