临沧锗矿褐煤的稀土元素地球化学  

REE geochemistry of lignites in Lincang germanium deposit, Yunnan Province

作　　者：戚华文[1] 胡瑞忠[1] 苏文超[1] 漆亮[1] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学开放研究实验室,贵州贵阳550002

出　　处：《地球化学》2002年第3期300-308,共9页Geochimica

基　　金：国家杰出青年基金(49925309);国家重点基础研究发展规划项目(G1999042310)

摘　　要：采用ICP-MS测定了临沧锗矿中51件含矿煤、5件无矿煤的稀土元素和锗含量,并与含矿煤层中热水成因燧石及基底白云母花岗岩进行对比,探讨了含矿煤与无矿煤的稀土元素地球化学及其与锗超常富集的关系,得出几点初步认识:(1)无矿煤和含矿煤的稀土元素主要来自基底白云母花岗岩;(2)无矿煤属正常沉积产物,含矿煤组成叠加了热水活动产物;(3)形成临沧锗矿的锗可能主要由热水活动带来。The Lincang germanium deposit is located in the Bangmai coal bearing clastic rock basin with granites as the basement in Lincang County, western Yunnan Province. There are three coal bearing cycles (N1b2, N1b4 and N1b6) in the basin. Germanium present in the form of organic compounds mainly occurs in the lignite of the first coal cycle (N1b2), which is close to the basement granites. This cycle is mainly composed of clastic rocks, coal seams, layered siliceous rocks and carbonatites. REE geochemistry of lignites and its relationship with germanium mineralization is discussed based on the study of rare earth element compositions and germanium content of Ge rich lignites from the first cycle (N1b2) and non germanium lignites from the second cycles (N1b4), and the comparison with hydrothermal genetic siliceous rock in the first cycle, and the basemental two mica granites in the Lincang germanium deposit. The results indicate that Ge rich lignites contain 25.477～2522.906 μg/g germanium, ΣREE varies from 5.070 to 148.225 μg/g, while non germanium lignites contain less than 0.781 μg/g germanium and ΣREE varies from 32.186 to 46.803 μg/g. Both the Ge rich lignite and non germanium lignites have distinct negative Eu anomaly and weak positive Ce anomaly. A negative correlation was found between Ge content and LREE/HREE, (La/Yb)N and (Gd/Yb)N in the Ge rich lignites. Compared to non germanium lignite, especially when germanium content is less than 200 μg/g, the REE pattern of low germanium lignite is plan, while germanium content increases, HREE relatively concentrates. The North American Shale normalized REE patterns of non germanium lignite and Ge rich lignite are similar to the basemental granites, suggesting that the REE of Ge rich lignites and non germanium lignites came from the muscovite granites in the basement of the sedimentary basin. The results also show that the NAS normalized REE patterns of non germanium lignites and low germanium lignites are plain, suggesting that they formed

关 键 词：地球化学 稀土元素 褐煤 热水 云南 热水活动 锗矿床 花岗岩 

分 类 号：P618.75[天文地球—矿床学] P595[天文地球—地质学]