利用扫描电镜-电子探针研究四川杨柳坪镍铜硫化物矿床铂钯的赋存状态及沉淀机制  

Analysis of the Occurrence of Platinum-Palladium and Precipitation Mechanism by SEM and EPMA in the Ni-Cu Sulphide Deposits from Yangliupin,Sichuan Province,China

作　　者：戴婕[1,2,3] 徐金沙[2] 杜谷[2] 王坤阳[2] 

机构地区：[1]成都理工大学,四川成都610059 [2]中国地质调查局成都地质调查中心,四川成都610081 [3]国土资源部沉积盆地与岩相古地理重点实验室,四川成都610081

出　　处：《岩矿测试》2015年第2期161-168,共8页Rock and Mineral Analysis

基　　金：铂族元素赋存状态的系统分析与研究方法(1212011120273);西藏大型矿床成矿专属性研究(1212011221073)

摘　　要：本文利用电子探针和配备能谱分析功能的扫描电镜对四川杨柳坪镍-铜硫化物矿床中铂钯的赋存状态进行了研究。结果表明,铂以独立矿物相砷铂矿和自然铂存在;钯以碲化物、碲铋化物、碲锑化物、锑化物及自然钯独立矿物相存在,也以类质同象形式分布在碲镍矿中（钯含量约10%）,另外还以锑铋钯碲矿、六方锑碲钯矿、碲钯矿独立矿物相存,并以类质同象形式分布在Vavrinite（钯含量5%）和砷铂矿（钯含量1%~5%）中。杨柳坪矿床中铂钯元素沉淀与贱金属矿物（BMS）及晚期热液蚀变矿物蛇纹石、方解石密切相关,其沉淀经历了3个阶段：1早期高温阶段（1200~900℃）,铂钯元素沉淀并包裹在BMS中;2中期中高温阶段（650~250℃）,分离结晶作用使铂钯元素沉淀并分布BMS矿物的边部,同时该阶段热液来源的铂钯元素沉淀于BMS粒间;3晚期热液蚀变阶段（500~300℃）,热液蚀变作用引起铂钯元素沉淀在蚀变矿物中或嵌布在BMS裂隙。本文研究成果为认识该矿床及同类型镍-铜硫化物矿床的铂钯成矿过程提供了新的依据。The occurrence of Pt and Pd in Cu-Ni suphide deposits from Yangliupin,Sichuan Province has been studied successfully by Electron Probe Microscope（ EPMA） and Scanning Electron Microscope（ SEM） with energy analysis function. The result showed that Pt existing in the form of sperrylite and native platinium,and Pd was either mainly in the form of individual minerals such as testibiopalladite and hexatestibiopanickelite,or in the form of hexastibiopalladinite,michenerite and merenskyite. Pd was also found as isomorphism form in the Vavrinite（ Pd5%）,sperrylite（ Pd 1%-5%） and melonite（ Pd 10%） which was initially found in the deposit. The precipitation of Pt and Pd was closely related to base metal sulfide（ BMS） and altered minerals such as serpentine and calcite. The process can be described as follows： in the first stage with high temperature（1200-900℃）,Pt and Pd was precipitated and then included in BMS; in the second stage with high-moderate temperature（ 650-250℃）,Pt and Pd was precipitated on the side or in the crack of BMS with fractional crystallization or hydrothermal function respectively; and in the last stage with the temperature of 500-300℃,Pt and Pd was precipitated in the alteration minerals or in the crack of BMS by reason of alteration. The analysis results provide the scientic basis for other Ni-Cu sulfide of the same type.

关 键 词：扫描电镜 电子探针 杨柳坪 镍-铜硫化物矿床 铂 钯 赋存状态 沉淀机制 

分 类 号：P575[天文地球—矿物学]