中文摘要：

通过对内蒙古额济纳盆地小狐山剖面沉积物中酸溶组分稀土元素含量及其相关指标、分布模式的分析，讨论了剖面中稀土元素指标δCe-∑REE与沉积相、沉积环境之间的关系。分析结果表明剖面沉积物酸溶组分中稀土元素丰度均值为7．24μg／g（不包括Y），其中LREE含量占稀土总量的88．67％；且各层的稀土分布模式均为轻稀土适度富集缓右倾斜型、Eu呈负异常模式，但各相位地层的LREE富集程度与分配模式存在差异。由于小狐山剖面中沉积地层的自身岩性、沉积粒径、矿物结构组成以及气候环境变化等因素均可能会引起REE分异。因此，通过δCe-∑REE图并结合三次回归曲线，可以很好地将不同沉积相得物质有效的区分开来。小狐山剖面除极少数的几个样品（水下沉积砂）之外，其余的均落在三次多项式回归曲线上部；而风成砂层则几乎全部落在回归曲线之下；此外，对于风沙-河流作用下的混合样品也有较好识别，河流过渡相的样品则分布在曲线上或与之相邻近。此研究结果得到了柴达木贝壳堤沉积物的REE数据的验证，运用此方法可以为直观的判别剖面中的不同沉积相，并为定量化划分地层提供依据。

英文摘要：

Based on the concentration, ratios and distribution pattern analysis of the rare earth elements （REEs）in the acid fractions at the Xiaohushan section in Ejina Basin, Western Inner Mongolia, We have studied the relationship between δCe-∑REE plot and the sedimentary facies for the study section. Our results show that the REE average concentration in AS is 7.24 μg/g（ except element Y） and that LREEs are strongly enriched （ about 88.67%）. Although each sedimentary facies of the section have similar REE distribution patterns,which are slightly rich in light earth rare elements （LREEs） , with slightly right-tilting and negative Eu anomaly, they have fractionation in distribution patterns. Because the fractionation of REE in each sedimentary facies caused by their lithology,grainsize,mineral composition and the fractionation of REE during the environmental changes of lake, the δCe-∑REE plot and regression equation can clearly distinguish sediments from lacustrine deposits and the eolian sand. The boundary can be described as an orthogonal polynomial equation by the ordinary linear regression with sediments from the lacustrine deposits located above the curve and the sediments from the eolian sand located below the curve. And the plot also can better identify samples formed in a combined effect of wind and water. This method can be used to distinguish the sediments from different sedimentary facies visually and quantitatively, which is verified by the data of the Shell bar section in the Qaidam Basin.