中文摘要：

文中总结了北京平原永定河、潮白河流域钻孔沉积物中稀土元素分布特征,两流域沉积物稀土元素总量∑REE、轻重稀土比（LREE/HREE）及轻（La/Sm）N、重（Gd/Yb）N稀土分馏特征差异较为显著。粒度对沉积物稀土分布（总量、轻重稀土比及分馏特征）有一定影响;各流域沉积物均表现为轻稀土相对富集、弱Eu负异常的球粒陨石标准化曲线。细颗粒沉积物稀土分馏特征（La/Yb）N有较好的物源示踪意义。根据沉积物（La/Yb）N值对永定河、潮白河交互沉积区不同深度沉积物进行了物源示踪,不同深度上沉积物来源不同。此外,同一流域上、中、下游沉积物稀土分馏特征不同。常量元素Al2O3/Fe2O3与稀土元素（La/Yb）N划分结果相符,但精度低于稀土元素物源分析。

英文摘要：

Based on borehole logging,sediment sampling and analysis,we systematically evaluated the REE distribution characteristics of the sediment from different boreholes in Yongding River catchment and Chaobai River catchment of Beijing Plain.Results show that ∑REE,LREE/HREE,（La/Sm）N,and（Gd/Yb）N of sediments have significant differences between Yongding River catchment and Chaobai River catchment.REE characteristics were generally controlled by grain size of sediments.The chondrite-normalized REE patterns show LREE enrichment and weak Eu negative anomaly.The（La/Yb）N of fine fraction is a good indicator for provenance identification.According to（La/Yb）N,sediments obtained from different depths of several boreholes in the interactive sedimentation region have different sources.In addition,sediments from upper,middle and lower reaches of Yongding River catchment and Chaobai River catchment were identified by means of REE fractionation characteristics.The result is consistent with the provenance identification using the ratio of Al2O3 to Fe2O3.However,REE fractionation can be used for the provenance analysis more precisely in comparison with major composition ratios.