摘要
东海陆架EA1孔和EA5孔沉积物化学成分变化范围较大,与东海陆架表层沉积物相比,钻孔沉积物的Si、Al、Mg、Mn、Ti、P、Ba、Zr、Co、Ni、Cu、Zn、Cr明显偏高,而Fe、Na、Ca、Sr、Li、U明显偏低,与全球大陆地壳化学组成相比,钻孔沉积物的Si、Li、Rb、Ba、Th、Zr、Hf、Cu、Zn、Pb偏高,而Al、Na、Ca、Mg、Fe、Mn、Ti、P、Sr、U、Co、Ni、V、Cr偏低。钻孔沉积物的化学成分在垂向上具有明显变化,主要受岩性和沉积环境的控制。钻孔沉积物中元素的富集因子(EF)均小于10,接近于1,表明钻孔沉积物主要来自大陆地壳。一些元素因分异或外来物质加入而富集,一些元素则因分异带出而亏损。钻孔沉积物源区的DF值判别表明,钻孔沉积物与现代黄河、长江沉积物均有亲缘关系,可能是在末次冰期最盛期,由于气候带南移,干旱区域扩大,在古长江搬运沉积物中类似现今黄河沉积物的干旱组分明显增加,从而导致了地球化学示踪结果的长江与黄河双重性,或者说古气候的变化导致了古长江搬运物质成分的变化。
Two late Quaternary sediment cores from the East China Sea shelf,EA1 and EA5,have been analyzed for major and trace elements(Si, Al, K, Na, Ca, Mg, Fe, Mn, Ti, P, Li, Ba, Th, Zr, Hf, Cu, Zn, Pb).Compared with surface sediments of the shelf, Si,Al,Mg, Mn, Ti, P, Ba, Zr, Co, Ni, Cu, Zn, and Cr are higher, whereas Fe,Na,Ca,Sr,Li,and U are lower in the sediment cores. Si, Li, Rb,Ba, Th, Zr, Hf, Cu, Zn , Pb are higher,and Al, Na, Ca, Mg, Fe, Mn, Ti, P, Sr, U, Co, Ni, V, Cr are lower in the cores than those in the continental crust abundance. Six geochemical zones controlled by lithologic and sediment environments, have been recognized in the cores through vertical changes in chemical composition. Rich factors of elements in the cores are less than 10, and near 1, so the sediments mainly come from continental crust. Geochemical tracing of sediment sources of the cores suggests that the sediments were related to modern sediments of the Yangtze River and Yellow River, which can be explained by two reasons, one is that the Yellow River came into the basins in the last glacial period, the other is that the Yangtze River in the last glacial period was similar to the modern Yellow River,but differed from the modern Yangtze River.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2002年第4期21-28,共8页
Marine Geology & Quaternary Geology
基金
黄
东海浅钻古环境研究(126-03-15-07)