东海陆架 SFK-1孔微量元素地球化学特征与物源意义

摘要

The geochemical information from trace elements of the continental shelf sediment from East China Sea is a significant indicator to the stratigraphic division and provenance analysis.The trace elements of sedi-ments derived from drillhole SFK-1(82.90 meters in depth)which was located at Xihu depression in the conti-nental shelf of East China Sea were analyzed and their provenances were discriminated.According to the chan-ging law of trace element contents and their ratios,the sediments from drillhole SFK-1 can be divided into eight layers,which reflect the fluctuation of sea level and the change of sediment sources in East China Sea since the late last interglacial cycle (warm period).Combined with factor analysis,the scatter diagrams of U /Th vs.(Zr+Hf)/(Al2 O3 +TiO2 )and Th /Co vs.TiO2 /Zr were drawn to determine the material source of sediments from drillhole SFK-1.The results revealed that the material sources of sediments mainly come from the Changjiang River,and sediments in the middle part of the drillhole were apparently influenced by materials from the Yellow River.The results also indicated that in the case of unchanging sediment sources,the changes of climate and sedimentary environment had little effect on transformation and redistribution of chemical elements of sediments in the study area.%为研究东海陆架微量元素地球化学信息对于地层划分与物源分析的指示意义，对东海陆架西湖凹陷区 SFK-1孔沉积物作了微量元素地球化学分析和物源判别。根据微量元素含量及比值的变化，可将 SFK-1孔（孔深82．90 m）岩心划分为8层，它们分别反映了末次间冰期（暖期）晚期以来东海海面波动以及沉积物物源的变化。运用因子分析、U /Th 与（Zr ＋Hf）/（Al2 O3＋TiO2）和 Th/Co 与 TiO2/Zr 的散点图等方法分析了 SFK-1孔沉积物的物质来源，结果显示该孔沉积物主要来源于长江，黄河物质对该孔中部沉积物有较明显影响。不同指标散点图研究表明，在沉积物物质来源不变的情况下，气候和沉积环境的变化对该区域沉积物化学元素组成进行的改造和再分配影响不大。