渤海海峡表层沉积物稀土元素的分布特征与物源判别

Distribution and origination of rare earth elements in surface sediments of the Bohai Strait

对渤海海峡383个站位表层沉积物的稀土元素进行了系统分析,旨在揭示其分布特征、影响因素、主要物质来源以及迁移机制。结果表明:渤海海峡沉积物稀土元素总量(∑REE)为44.85~283.00μg/g,平均含量为166.33μg/g,高值区主要分布在沉积物粒度较细的西部和南部海域,低值区分布在沉积物粒度较粗的东北部海域,呈轻稀土富集、重稀土亏损的特点。通过对∑REE以及部分特征参数与粒度、化学蚀变指数和部分元素进行相关性分析,发现∑REE与沉积物粒度平均粒径呈正相关,指示研究区稀土分布与沉积物粒度和物源密切相关。渤海海峡稀土元素的上地壳和球粒陨石配分模式与黄河及辽东湾河流物质具有相似性,表现出较强的陆源性特征,而与鸭绿江和朝鲜半岛河流差异较大,表明物源主要来自中国大陆。利用球粒陨石标准化计算的δEu-(La/Yb)_(N)和(Gd/Yb)_(N)-(La/Yb)_(N)指标进行物源判别,结果显示渤海海峡物质主要来源于黄河,而研究区东北部则为黄河与辽东湾河流混合来源。辽东湾环流及渤海沿岸流的共同作用影响了渤海海峡的沉积格局。

To understand the material exchange between the Yellow Sea and the Bohai Sea,the distribution and origination of rare earth elements(REE)in surface sediments from 383 stations in the Bohai Strait were studied,the influencing factors,main sources of materials,and migration mechanisms of the REE were analyzed systematically.Results indicate that the total REE content(ΣREE)in the sediments of the Bohai Strait ranges from 44.85 to 283.00μg/g,on average o of 166.33μg/g.The high-value areas were distributed in mainly the western and southern sea areas with finer sediments,while the low-value areas were located in the northeastern sea areas with coarser sediments,showing characteristics of light REE enrichment and heavy REE depletion.Correlation analysis betweenΣREE and certain characteristic parameters to grain size,chemical index of alteration(CIA),and some elements,we found thatΣREE is positively correlated with sediment mean grain size,indicating a close relationship between REE distribution and sediment grain size/provenance.The distribution patterns of REEs in the upper continental crust and chondritic meteorites in the Bohai Strait show similarities with the material carried by the Huanghe(Yellow)River and rivers surrounding the Liaodong Bay,indicating a distinct terrigenous imprint of riverine materials.In contrast,there are significant differences with the Yalu River and rivers in the Korean Peninsula,indicating that the primary source of the material is from the Chinese mainland.Using the standardized calculation of δEu-(La/Yb)_(N) and(Gd/Yb)_(N)-(La/Yb)N indices based on chondritic meteorites,source discrimination was conducted.The results indicate that the material in the Bohai Strait mainly originates from the Huanghe River,while in the northeastern sea areas of the Bohai Strait,it is a mixture of the Huanghe River and rivers surrounding the Liaodong Bay.The combined effect of Liaodong Bay circulation and Bohai Sea coastal current affects the sedimentary patterns in the Bohai Strait.