太原西山矿区杜儿坪井田夹矸地球化学特征及其地质意义

Geochemistry of Trace Elements in Partings of the Duerping Coal Mine,Xishan Coalfield,Taiyuan(North China) and Its Geological Implication

为探明太原西山矿区杜儿坪井田夹矸的地球化学特征及其地质成因,用X射线衍射分析(XRD)、电感耦合等离子体质谱(ICP-MS)、电感耦合等离子体发射光谱(ICP-OES)、氢化物-原子荧光光谱(HG-AFS)、发射光谱法(ES)等方法对杜儿坪井田2号、3号和8号煤层夹矸进行了矿物学和地球化学特征研究。结果发现2号、3号和8号煤层夹矸中矿物以高岭石、石英为主;与华北上地壳相比,杜儿坪夹矸中富集有害微量元素Cd、Se、Mo、Pb、Be、Cu、Th和U,山西组夹矸中有害元素含量大于太原组(除Mo、Pb和U);所有夹矸样品中Li、Ga的含量超过了工业品位,其工业利用价值值得关注;山西组夹矸稀土元素总含量高于太原组夹矸,所有夹矸稀土元素分配模式反映其与陆源碎屑关系密切;通过分析得到该区夹矸形成期间的陆源碎屑主要来自北部的花岗岩;太原组夹矸形成过程受海水影响;稀土元素与Al和Si等造岩矿物的聚类分析表明,夹矸中稀土元素主要赋存于高岭石等黏土矿物中。

In order to further ascertain the geochemical characteristics and geologic origin of the trace element,XRD,ICPMS,ICP-OES,HG-AFS,and ES were used to study the geochemistry and mineralogy of gangue in 3 main coal seams of the Duerping Coal Mine,Xishan coalfield,Taiyuan,Shanxi. The results revealed that kaolinite is the major mineral and quartz is the second major mineral of the partings of all samples. Compared with the north China earth＇s crust,coal gangues of the Duerping Coal Mine enrich hazardous elements,such as Cd,Se,Mo,Pb,Be,Cu,Th and U. The contents of the hazardous elements are more abundant in the partings of the Shanxi Formation,Permian Period than in the Taiyuan Formation,Carboniferous Period（ except Mo,Pb and U）. In all samples,the contents of Li and Ga are very high,even higher than the industrial grade of other associated deposits,therefore their industrial utilization deserves more attention. The values of REEs are higher in Shanxi Formation coal partings than in Taiyuan Formation coal partings. Distributions pattern of REEs in all partings shows close relations with terrigenous clastics. We concluded that the origin of the terrigenous clastics is the granite in the north,and that the sedimentation process of the Taiyuan Formation was influenced by seawater. The clustering analysis on contents of REEs and rock-forming elements showed that the REEs in the partings of the Duerping coal mine occur mainly in kaolinite and other clay minerals.