云南巍山笔架山锑矿床辉锑矿稀土微量元素特征及其矿床成因意义  

CHARACTERISTICS OF RARE EARTH AND TRACE ELEMENTS OF STIBNITE FROM THE BIJIASHAN ANTIMONY DEPOSIT,SOUTHWEST YUNNAN:IMPLICATIONS FOR ORE GENESIS

作　　者：肖昌浩 李龚健[2] 刘欢[3] 梁坤 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]中国地质科学院矿产资源研究所,北京100037 [4]黑龙江省第四地质勘察院,哈尔滨150036

出　　处：《地质力学学报》2016年第2期310-324,共15页Journal of Geomechanics

基　　金：地质力学研究所基本科研业务费项目(DZLXJK201505);国家重点基础研究发展规划(973)项目(2015CB452606;2009CB421008);国土资源部公益性行业科研专项(201411024-3)

摘　　要：以笔架山锑矿床为研究对象,在矿床精细解剖基础上,利用辉锑矿金属矿物ICP-MS分析,指示成矿流体来源和性质。研究结果显示,辉锑矿轻稀土强烈富集,分馏程度高,Tb、Dy、Eu呈显著的正异常,显著的正异常稀土配分模式,与喜马拉雅期富碱斑岩的稀土配分模式具有相似性。此外,辉锑矿矿物以其强Sr和Ba正异常的微量元素特征,与喜马拉雅期富碱斑岩中高含量Sr和Ba的特征一致。辉锑矿矿物的Y/Ho比值变化较大,其比值随辉锑矿的氧化程度增大和产出海波高度增高而逐渐增大。对比不同流体系统的Y/Ho比值发现氧化程度较大和海拔较高的辉锑矿Y/Ho比值与现代海水的Y/Ho比值接近,氧化程度较低的辉锑矿Y/Ho比值与莲花山岩体Y/Ho比值接近,指示成矿流体可能是岩浆与大气降水不同程度的混和。H-O同位素研究显示出成矿热液来源于岩浆水和大气降水的混合。Pb同位素显示壳、幔源多源铅的特征。S同位素表明辉锑矿的S主要为生物与岩浆热液来源硫的混合。综合研究认为,该矿床是一个受层间构造破碎带控制的位于岩浆远端的低温热液矿床。Taking the Bijiashan antimony deposit as the research object,we reveal the source and nature of ore-forming fluid using ICP-MS analysis of stibnite based on the fine dissection of ore deposits. The REE patterns of stibnite show enrichment of LREE with the intense fractionation,with obvious Tb and Dy positive anomaly and Eu positive anomaly,which is similar with the REE patterns of the Himalayan alkali-rich porphyry. Furthermore,the characteristics of strongly Sr and Ba positive anomaly in the trace element of stibnite,is consistent with that of the Himalayan alkalirich porphyry. The Y / Ho ratios of stibnite increase along with the increase of altitude and degree of oxidation. The Y / Ho ratios of stibnite with high degree of oxidation is similar with the Y / Ho ratios of sea water and the Y / Ho ratios of stibnite with low degree of oxidation is similar with the Y / Ho ratios of the Lianhuashan alkali-rich porphyry,which suggests that ore-forming fluid may be from the mixture of magmas and atmospheric water and that is also supported by H-O isotope study. Isotope analysis reveals that Pb is from multiple sources and S of stibnite is a mixture of biological sulfur and magmatic sulfur. Results display that the deposit controlled by interformational fracture zone is an epithermal deposit which formed in distal volcanic settings.

关 键 词：笔架山锑矿 矿石组构 ICP-MS 矿床成因 低温热液矿床 

分 类 号：P618.66[天文地球—矿床学]