贵州西部二叠系主采煤层稀土元素分布特征及影响因素分析

Distribution Characteristics and Influence Factors of Rare Earth Elements in Guizhou Permian Coal Measure Strata

摘要: 贵州是我国煤炭资源蕴藏极为丰富的省份，是中国重要的煤炭生产基地，但煤层中元素地球化学分布情况研究程度低，对贵州煤炭资源有效利用是一项严重的欠缺。通过对贵州西部二叠系主采煤层稀土元素地球化学研究，获得了大方、黔西、威宁、赫章、织金等地主采煤层稀土元素分布特征，并得出煤中稀土元素主要来源于陆源碎屑，与峨眉山玄武岩有关。煤层中稀土元素的含量受到沉积环境和陆源区母岩性质的影响，稀土元素随着从玄武岩风化碎屑多的三角洲平原环境，到受海水影响较大的潮坪环境，稀土元素逐渐被稀释，靠近陆地的成煤环境稀土含量较高，远离陆地的成煤环境形成的煤层中稀土含量低。根据这种分布规律，提出了利用稀土元素地球化学来区分贵州西部成煤环境的新思路，这对解决贵州西部三角洲成煤还是潮坪成煤问题具有现实意义。

Abstract: Guizhou has abundant coal resources which is an important coal production base in China, but few researches have been done on the element geochemistry of coal measure strata in Guizhou Province, and the effective utilization of coal resources in Guizhou is a serious defect. Based on element geochemical studies of the main Permian exploitable coal measure strata in western Guizhou, geochemical distribution characteristics of the rare earth elements in the main exploitable coal measures have been revealed in the regions of Dafang, Qianxi, Weining, Heizhang, Zhijin, etc. of Guizhou province. The REEs in coals are mainly continental origin, associated with Emeishan basalt. Contents of REEs in coal seam are affected by sedimentary environments and lithology qualitative in terrigenous areas. REEs are gradually diluted from delta plain environment, which contains more basalt weathering debris, to the tidal flat environment greatly influenced by the water. The contents of REEs are higher when coal-forming environment is closer to land, while the contents of REEs are lower when coal-forming environment is away from land. According to the rules of distribution of REEs in coal measures, a new idea has been put forward to make use of the geo-chemical composition characteristics to classify coal-forming environments, which is of great sig-nificance in dissolving the problem of whether coal measures were formed either in delta envi-ronment or in tidal-flat environment in western Guizhou.