华北晚古生代煤系I/S间层粘土岩稀土元素地球化学特征

摘要

通过ICP和INAA方法对华北几个晚古生代煤田(煤矿区)的I/S间层粘土岩样品进行了稀土元素(REE)地球化学特征研究。结果表明，无序间层粘土岩REE含量较低，并具中-弱Eu正异常为特征；IS有序间层粘土岩以REE含量高，中-强Eu亏损为特征。两种I/S间层粘土岩的REE含量及特征均与NASC有所不同。物源分析表明，无序间层粘土岩主要由中性火山碎屑(岩)在原地蚀变、转化而成，而有序间层粘土岩则是由酸性岩蚀变而成。%The clay rock samples from the Late-Paleozoic coalfields of Northern China are studied with ICP and INAA methods.The disordered I/S clay rock is characterized by lower REE contents and the middle to weak positive anomaly of Eu,but the ordered one is of higher REE contents and the strong to middle negative anomaly of Eu. The clay rocks differ form NASC in the REE contents and characteristics. The results show that the disordered and ordered clay rocks are respectively formed by intermediate and acidic pyroclasts in the sedimentary basins.