晚更新世以来南黄海北部泥质区沉积物元素的分布及来源分析

为研究南黄海北部泥质区元素地球化学特征对于地层划分与物质来源的指示意义，对南黄海北部DLC70-3孔(孔深71.20 m)沉积物作了元素地球化学分析和物源判别。根据元素含量及比值的变化，可将DLC70-3孔岩心划分为5层，它们分别反映了末次间冰期(暖期)晚期以来黄海海面波动以及沉积物物源的变化。运用判别函数、MgO/Na₂O与CIA的散点图等方法分析了DLC70-3孔沉积物的物质来源，结果显示该孔沉积物主要来源于黄河，长江物质对该孔中上部及下部沉积物有较明显影响。DLC70-3孔物源指数反映0~4.50 m和27.80~38.80 m沉积物以黄河源为主，4.50~27.80 m、38.80~55.00 m和55.00~71.20 m沉积物以长江源为主；可见黄河从晚更新世中期到现代对南黄海北部沉积起着重要作用，而长江物质在晚更新世早期开始对南黄海北部沉积就有明显影响。

Distribution and Source Analysis of Elements from Sediments in the Northern South Yellow Sea since the Late Pleistocene

The sediment samples derived from drillhole DLC70-3(71.20 meters in depth) in the northern South Yellow Sea were measured for analysis of element geochemistry and their provenances were discriminated with the purpose of studying the indicator significance of element geochemistry information for the stratigraphic division and provenance analysis of mud area in northern South Yellow Sea. According to the changing law of element contents and their ratios，the sediments from drillhole DLC70-3 can be divided into five layers, reflecting the fluctuation of sea level and the change of sediment sources in northern South Yellow Sea since the late of the last interglacial cycle (warm period). Combined with discriminate function，the scatter diagrams of MgO/Na2O vs. CIA were drawn to determine the material source of sediments from drillhole DLC70-3. The results revealed that the material sources of sediments mainly came from the Yellow River，and sediments in the upper-middle and in the lower of the drillhole were apparently influenced by materials from the Changjiang River. The sediments above the depth of 4.50 m in the upper and between 27.80 m and 38.80 m in the middle of drillhole DLC70-3 mainly belong to the Yellow River source; the sediments from 4.50 m to 27.80 m in the upper-middle，from 38.80 m to 55.00 m in the lower and from 55.00 m to 71.20 m at the bottom were mainly derived from the Changjiang River. It is concluded that the Yellow River is playing an important role in northern South Yellow Sea at the middle stage of Late Pleistocene and the Changjiang River has started to obviously influence northern South Yellow Sea since early Late Pleistocene.