西藏邦铺铅锌矿床S、Pb、C、O同位素组成及成矿物质来源研究  

Sulfur,Lead,Carbon and Oxygen Isotope Composition and Source of Ore-forming Materials of the Bangpu Pb-Zn Ore Deposit in Tibet

作　　者：王立强[1] 罗茂澄[2] 袁志洁[3] 陈伟[4] 冷秋锋[4] 张学全 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院,北京100037 [4]成都理工大学地球科学学院,四川成都610059 [5]西藏地勘局地热地质大队,西藏拉萨850000

出　　处：《地球学报》2012年第4期435-443,共9页Acta Geoscientica Sinica

基　　金：国家973项目(编号:2011CB403103);国土资源地质大调查项目(编号:1212010012005)联合资助

摘　　要：邦铺铅锌矿床系邦铺钼铜矿区斑岩矿化体外围形成的矽卡岩型铅锌矿床;矿石品位较富,成矿元素以铅锌为主,基本不含铜。文章以矿床中主要金属硫化物为研究对象,采用S、Pb同位素研究方法对矿床成矿物质来源进行探讨。结果表明,矿石金属硫化物δ34S值分布范围较宽,但主要集中于-3.7‰～-0.7‰之间,具塔式分布特征,硫主要来源于岩浆;矿石铅同位素组成稳定,为正常普通铅,矿石铅的高μ值(大于9.58)及构造环境演化图解中样品点的分布特征指示矿石铅主要来源于上地壳物质。与驱龙外围知不拉、甲玛矽卡岩矿体对比研究发现,3个矿床硫均为岩浆来源;而金属物质来源空间上则显示出一定的规律,驱龙—甲玛—邦铺矿集区由南向北壳源物质的混染作用不断增加;大理岩及方解石碳-氧同位素组成特征显示矿床成矿流体中碳源主要来自于岩浆,碳酸盐岩地层提供了部分成矿物质。The Bangpu Pb-Zn deposit, formed in the periphery of the porphyry mineralization body of the ore district, is a skarn deposit with relatively rich ore grade, and the ore-forming elements are dominated by lead and zinc, without copper basically. Main metal sulfides were objects of this study, and S and Pb isotopic methods were used to investigate the source of the ore-forming minerals. The results show that the δ^34S values of the ore metal sulfides have a wide distribution, and mainly vary in the range of -3.7‰- -0.7‰, with the characteristics of tower distribution, and that these sulfur materials were mainly derived from the magma. Lead isotopes of the ore have stable composition and are positive common lead. The high μ values （larger than 9.58） of ore lead and the distribution characteristics of the data points in the evolution diagram of tectonic environment indicate that the ore lead was mainly derived from the upper crust. A comparison between this deposit and the nearby Zhibula and Jiama deposits shows that sulfur of these three deposits was exclusively derived from magma, and their metal materials show a certain regular pattern in source space, i.e., the contamination of crustal source material increased from south to north in the Qulong-Jiama-Bangpu ore district. Carbon and Oxygen isotope compositions of marble and calcite show that carbon in ore-forming fluid was mainly derived from the magma whereas the carbonate formation provided parts of other ore-forming materials.

关 键 词：硫同位素 铅同位素 碳-氧同位素 成矿物质来源 壳源混染 成矿流体 邦铺 

分 类 号：P618.4[天文地球—矿床学] P597.2[天文地球—地质学]