The rare earth element compositions of the Changjiang (Yangtze) and Huanghe (Yellow) river sediments
The rare earth element compositions of the Changjiang (Yangtze) and Huanghe (Yellow) river sediments
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DOI：
10.1016/s0012-821x(02)00715-x
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发表时间：
2002-07
影响因子：
5.3
通讯作者：
Shouye Yang;H. Jung;Man-Sik Choi;Congxian Li
中科院分区：
文献类型：
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作者：
Shouye Yang;H. Jung;Man-Sik Choi;Congxian Li
对采自长江和黄河的34个样品进行了稀土元素组成分析。虽然长江沉积物中的稀土元素含量高于黄河沉积物中的稀土元素含量，但前者变化较小。相对于上陆壳，大块样品和酸浸组分具有凸起的稀土配分模式和中等的稀土富集度，而剩余部分则呈现平坦的配分模式。源岩成分是稀土元素组成的主要控制因素，风化作用次之。两条河流沉积物中粘土矿物的稀土含量较高，表明粒度对稀土元素组成有一定的影响。重矿物约占沉积物中稀土总量的10-20%。磷灰石在河流沉积物中很少见，对REE含量的贡献不到2%，但其他重矿物如辉石、尿晶石和锆石是剩余稀土组分的重要储集层。在长江沉积物中，铁-锰氧化物相约占稀土总量的14%，这可能是控制可浸出物中稀土分馏的重要因素之一。
Thirty-four samples from the Changjiang and Huanghe were analyzed to characterize their rare earth element (REE) compositions. Although REE concentrations in the Changjiang sediments are higher than those of the Huanghe sediments, the former are less variable. Bulk samples and acid-leachable fractions have convex REE patterns and middle REE enrichments relative to upper continental crust, whereas flat patterns are present in the residual fractions. Source rock composition is the primary control on REE composition, and weathering processes play a minor role. Grain size exerts some influence on REE composition, as demonstrated by the higher REE contents of clay minerals in sediments from both rivers. Heavy minerals contribute about 10–20% of the total REE in the sediments. Apatite is rare in the river sediments, and contributes less than 2% of the REE content, but other heavy minerals such as sphene, allanite and zircon are important reservoirs of residual REE fractions. The Fe–Mn oxides phase accounts for about 14% of bulk REE content in the Changjiang sediments, which could be one of the more important factors controlling REE fractionation in the leachable fraction.