CHARACTERISTICS OF Rb/Zr RATIO OF DLC70-3 CORE FROM SOUTH YELLOW SEA AND ITS ENVIRONMENTAL IMPLICATION SINCE LATE PLEISTOCENE
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摘要: 利用岩心扫描X荧光光谱仪(XRF Core Scanner)对南黄海DLC70-3孔沉积物进行1 cm间隔的元素扫描测试。钻孔沉积物中陆源元素Rb和Zr相对含量垂向变化具有极好的分层性,Rb和Zr相对含量在不同粒级中变化较大,Rb在细粒中的含量较高,而Zr则在粗粒级中富集; Rb/Zr值可以反映沉积物中黏土矿物和石英、长石的相对含量变化。研究认为DLC70-3孔沉积物的Rb/Zr值受到海平面变化和源区气候变化共同控制,其中源区的气候变化为主要控制因素,而海平面变化主要影响26.50~38.00 m(MIS 4)层位粗粒级沉积物的Rb/Zr值。Rb/Zr值显示在MIS 5和MIS 3期源区化学风化作用较强,与内陆黄土高原地区夏季风和化学风化指标的变化趋势一致,尤其是在MIS 3早期(40~60 ka)记录的化学风化作用非常强,反映了黄河流域地区出现强夏季风降雨过程。Abstract: The DLC70-3 core from South Yellow Sea was scanried with XRF Core Scanner in 1 cm interval. It is found that the terrestrial elements Rb and Zr in the sediments showed an excellent pattern of lamination in the vertical direction.And the relative contents of Rb and Zr change significantly in different grain-size fractions.Rb is high in the fine grained sediments while Zr is opposite. Rb/Zr ratios can reflect the change in relative content of clay minerals to quartz and feldspar. It is supposed that the Rb/Zr ratio of the sediments of the DLC70-3 core is controlled by both the sea level and climate changes in the source area, of which the latter one dominates, the section of 26.50~38.00 m(MIS 4)consisting of coarse grain-size sediments is mainly influenced by the sea level change.The Rb/Zr ratio indicates that the chemical weathering was strong in the source area during MIS 5 and MIS 3, which corresponds well to the variation trend of the summer monsoon and chemical weathering indicators in the inland Loess Plateau area, especially during the early MIS 3(40~60 ka).
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Key words:
- Rb/Zr ratio /
- chemical weathering /
- summer monsoon /
- Loess Plateau /
- South Yellow Sea
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