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

Geochemical characteristics of rare earth elements in I/S clay rocks in Late-Pateozoic coal measures of Northern China

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 。

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.