中晚全新世冲绳海槽沉积物物源组成特征及其控制因素

    Terrigenous sediment provenances and transportation mechanisms in the Okinawa Trough during the mid-to-late Holocene

    • 摘要: 冲绳海槽接收了来自周边大陆及岛屿的大量碎屑物质,但其物源组成特征在中晚全新世以来的时空变化规律及主控因素仍需深入探讨。本文基于AMS14C年龄,利用岩芯N029-13沉积物的稀土元素与粘土粒级Sr-Nd-Pb同位素,探讨了中晚全新世冲绳海槽北部沉积物的物源组成特征。结果表明,冲绳海槽北部沉积物主要来自黄河,但九州岛粗颗粒碎屑物质的贡献亦不可忽视。进而综合对比其他已发表数据,发现中晚全新世冲绳海槽中、南部沉积物以长江和台湾岛碎屑物质占主导。在冬季风强烈影响下,长江碎屑物质可跨过东海陆架经陆坡和海底峡谷进入冲绳海槽内,台湾岛碎屑物质则通过黑潮向北输运。

       

      Abstract: The Okinawa Trough has received large amounts of detrital material from surrounding continentals and islands. However, the spatiotemporal evolution of provenance characteristics and its governing mechanisms during the mid-to-late Holocene remain inadequately constrained. In this study, based on AMS14C dating, rare earth elements and clay-sized Sr-Nd-Pb isotopes of core N029-13 were compiled to investigate provenance composition in the Northern Okinawa Trough during the mid-to-late Holocene. The results indicated that fine-grained detrital material in the Northern Okinawa mainly came from the Yellow River, and coarse-grained detrital material probably came from the Kyushu Island. Furthermore, comprehensive comparison with other published data revealed that sediments in the central and southern Okinawa Trough were dominated by detrital material from the Yangtze River and the Taiwan Island. With the influence of the East Asian winter monsoon, the Yangtze-derived detrital material was transported into the Okinawa Trough via the East China Sea shelf, the continental slope and the submarine canyons, whereas Taiwan-derived detrital material was transported northward by the Kuroshio Current.

       

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