祁连—柴达木盆地北缘地区石炭系泥岩沉积地球化学特征

详细研究了祁连—柴达木盆地北缘地区石炭系泥岩的微量元素和稀土元素地球化学特征。各微量元素在各剖面及不同层位变化相当复杂 ,但仍有一定规律 ,这种变化与其物源供应和沉积成岩环境有关。各样品稀土总量变化较大 ,以甘肃永昌煤山子剖面总量最高 ;各泥岩样品轻稀土富集 ,Eu负异常 ,δEu介于 0 .4 4～0 .90之间。微量、稀土元素组合及比值的变化 ,显示物源区母岩为花岗岩和玄武岩的混合 ,稀土分布模式显示源岩为粘土岩、花岗岩和中性岩的混合 ,两者示物源一致。元素的丰度及其比值 ,反映当时水介质环境大部分为海相 ,亦有部分为陆相 ,与其它相标志所表征的结果是一致的。

EOCHEMICAL CHARACTERISTICS OF CARBONIFEROUS MUDSTONES IN QILIAN MOUNTAIN AND NORTHERN QAIDAM BASIN

The paper presents the geochemical characteristics of trace elements and REE in mudstones. Trace elements in mudstones vary significantly from one profile to another and from one formation to another, which is related to the provenance and environment geochemistry. The REE contents are different from one sample to another, the LREE is high, and δEu is 44—0.90. According to the trace element and REE associations, which suggests that the provenance maybe the mixing of granite and basalt. The REE distribution patterns suggest that the provenance is the mixture of claystone, granite and intermediate rock. In terms of the abundance of trace elements and their ratios, it is suggested that the palaeoenvironment is mainly marine, and sometimes continental.