知识与财富的链接
以辽河盆地东部凸起下二叠统山西组-上石炭统太原组暗色页岩为研究对象,采用ICP-MS方法研究页岩稀土元素REE分布特征。结果表明,研究区泥页岩样品中∑REE、∑LREE、∑HREE都相对北美页岩(NASC)、澳大利亚后太古宙页岩(PAAS)和全球平均大陆上地壳成分(UCC)富集。化学参数及REE配分曲线表明样品富集轻稀土元素,具有一定程度的Eu负异常、弱Ce异常和极明显的Tm负异常,配分曲线平行表明各岩样物源基本一致。Ce异常值及Eu异常值表明研究区泥岩沉积时气候湿润,水体呈氧化还原过渡环境。(La/Yb)N比值与配分模式曲线表明样品整体沉积速率较慢,距物源区较远,沉积速率从下至上逐渐升高。据物源和构造背景图解,山西-太原组泥岩物源为沉积岩与玄武岩的混合成因,源岩构造背景为大陆岛弧切割的岩浆岩。
In this study, REE concentrations of Shanxi-Taiyuan Formation shale, eastern uplift of Liaohe Basin were tested by means of ICP-MS. The content of ∑REE、∑LREE、∑HREE are higher than that of the NASC, UCC, PAAS. The characteristics of chemical parameters and REE distribution curve shows that LREE are abundant, with moderately negative anomaly of Eu, weak Ce anomaly, very obviously negative anomaly of Tm, and similarly provenances according to the paralleled curves of samples.The characteristics of Ceanom and Eu reflect the oxidizing-reducing transition in sedimentary water mediums environment and humid paleoclimate. The ratio of (La/Yb)N and distribution patterns suggest low sedimentary rate with still changing trend from low to high from bottom, far away from provenance. According to the source rocks and tectonic setting discrimination diagrams,the provenances of shanxi-taiyuan Formation were mainly mixture of sedimentary rock and basalt, with the tectonic setting of continental island arc cutting magmatic rocks.
