贵州锦丰(烂泥沟)金矿床含砷黄铁矿和脉石英及其包裹体的微量元素特征  

Trace Elements Features of the Vein Quartzs,Arsenian Pyrites and Their Fluid Inclusions in Jinfeng(Lannigou) Gold Deposit,Guizhou Province,China

作　　者：胡瑛[1] 陈懋弘[1,2] 董庆吉[1] 黄庆文[1] 

机构地区：[1]中国地质大学(北京),北京100083 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《高校地质学报》2009年第4期506-516,共11页Geological Journal of China Universities

基　　金："中央级公益性科研院所基本科研业务费专项资金(K2007-1-2);国家重点基础研究发展计划(973计划)(2007CB411407);中国地质调查局<全国重要矿产总量预测>(1212010633905)联合资助

摘　　要：贵州锦丰(烂泥沟)金矿是滇黔桂"金三角"目前已探明最大的卡林型金矿床。含砷黄铁矿是该矿床最主要的载金矿物,硅化及石英脉是最显著的热液蚀变类型。本文采用高精度电感耦合等离子质谱(ICP-MS)对含砷黄铁矿和脉石英及其包裹体的微量元素进行了测试,结果表明含砷黄铁矿富亲硫元素,并相对于围岩和上部地壳均强烈富集;亏损V,Sr及高场强元素。同生黄铁矿也具有类似的特征。脉石英除亲石元素含量高以外,还表现为亲硫元素以及Mo,Bi含量较高。但与上部地壳相比,绝大部分元素贫化。相应包裹体的微量元素含量普遍低于单矿物,但变化特征一致。结合矿物和包裹体的稀土元素分析,发现脉石英和含砷黄铁矿及其包裹体均表现为HFSE明显亏损,Th/La,Nb/La比值小于1,说明成矿流体为富Cl的流体。含砷黄铁矿及其包裹体中Co/Ni比值远小于1,反映成矿温度较低,推测成矿流体主要来源于以沉积建造水为主的盆地流体。Jinfeng （previously known as Lannigou） is the largest known Carlin-type gold deposit in the Yunnan-Guizhou-Guangxi triangle area of southwestern China. Arsenian pyrite is the most important Au-bearing mineral, and silicification with quartz veins is the well-marked hydrothermal aheration. The trace elements of arscnian pyrites, vein quartzs and fluid inclusions in these minerals were analyzed by ICP-MS in this paper. The results show that in contrast to wall rocks and upper crusl, the arsenian pyrites are enriched in chalcophile elements, but depleted in V,Sr and HFSE. The syngenetic pyriles bear the similar features. The vein quartzs have high lithophile elements contents, as well as chah;ophilc elements. Mo and Bi. However, compared with the upper crust, they are poor in most elements. The trace elements in fluid inclusions are usually lower than in corresponding hosting minerals, but with consistent variation features. Combining with the REE data of corresponding minerals and inclusions, it is clear that the arsenian pyrites, vein quartzs and fluid inclusions in these nunerals are depleted in HFSE, with the Th/La and Nb/La ratios less than 1, suggesting a Cl-rich character of the ore-forming fluids. The Co/Ni ratios of arsenian pyrites and fluid inclusions are also lower than 1, indieating a lower ore-forming temperature. Consequently, it is inferred that the ore-forming fluids were mainly derived from the sedimentary formation water of the basin.

关 键 词：含砷黄铁矿 脉石英 包裹体 微量元素 盆地流体 锦丰(烂泥沟)金矿 

分 类 号：P578[天文地球—矿物学] P595[天文地球—地质学]