贵州毕节地区煤层中稀土元素在含煤地层划分与对比中应用探讨

Discussion on the Role of REE in Stratigraphic Subdivision and Correlation in Coal Measures from Bijie City,Guizhou Province

稀土元素是良好的地质指示剂,以晚二叠世黔西毕节地区可采煤层中的REE(稀土元素)为研究对象,探讨REE在煤系地层对比、划分中的应用问题。结果显示:LREE(轻稀土元素)的含量在龙潭组与长兴组的界线附近存在着异常富集的现象,∑REE的含量在界线附近也存在着异常富集的现象。REE在界限附近的异常富集是其物源(间歇性和多旋回性喷发的峨眉山玄武岩)和成煤期频繁的海进海退共同作用的结果。因此,在具有相同物源的地区,可以利用稀土含量的变化,进行煤层和地层的对比、划分,并有可能研究海平面的变化。

REE is a good geological indicator. In order to understand REE role in stratigraphic subdivision and correlation, REE in Late Permian coal measure from Bijie City, western Guizhou Province, China have been studied. The results show that the contents of both individual LREE and ∑ REE in the boundary between Longtan Formation and Changxing Formation are sharply increased. This phenomenon is related to the REEs sources （gyration and disconti- nuity eruption Emeishan basalt） and the transgression-regression frequently. So we can subdivide and correlate the strata, even understand the sea-level change by studying REE of coal measure with same sources.