东菲律宾海表层沉积物来源的稀土证据

PROVENANCE OF SURFICIAL SEDIMENTS OF THE EAST PHILIPPINE SEA:EVIDENCE FROM RARE EARTH ELEMENTS

为进一步了解东菲律宾海表层沉积物的物质来源组成,对该海域30个深海黏土沉积物样品中的稀土元素含量及主要黏土矿物组成进行了测试分析,并基于简化后的稀土元素二端元混合模型定量计算了所研究沉积物中陆源风尘物质和当地火山物质的贡献。结果表明:随着与风尘源区——亚洲大陆距离的增加,陆源风尘物质对研究区表层沉积物的贡献程度呈现出逐渐降低的趋势;而当地火山物质的贡献变化则相反,其高值出现在研究区东部的帕里西维拉海沟附近。我们的计算结果与研究区特征黏土矿物含量及利用前人少量Sr同位素数据为参数的二端元混合方程得出的物质来源定量分析结果非常一致,从而证实了本文中所用到的简化计算模型及据其获得的物质来源组成结论的有效性。

To further understand the provenance of the surficial sediments in the East Philippine Sea,30 samples have been analyzed for rare earth elements（REE） compositions and clay mineral assemblages.Based on the REE data and a simplified two end-member mixing model,we quantitatively calculated the contributions of the eolian dust and the local volcanic debris to the study area.It shows that the contribution of the eolian dust to the study area is decreasing with the distance from the source area of the dust（i.e.,the Asian continent）,while the contribution of the local volcanic matter shows a converse trend,with high values near the Parece Vela Trench.The results are very consistent with the conclusion from clay mineral assemblages and 87Sr/86Sr data of the studied samples and the conclusions from the two end-member mixing equation provided by published literatures.It suggests that the simplified calculation model is valid for provenance study in this region.