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黏土矿物以其示踪洋流变化和揭示物源区陆地同时期气候变化的能力,近年来在南海东亚季风演化的研究中起到了重要作用.珠江作为南海北部陆源物质输入的重要河流之一,以往的研究还没有开展过详细的黏土矿物学工作.运用X射线衍射方法,系统地研究了珠江流域盆地(包括珠江主流、各支流和珠江口伶仃洋)表层沉积物的黏土矿物组合.结果显示,珠江流域盆地黏土矿物组合主要由高岭石(35%~65%)、绿泥石(20%~35%)和伊利石(12%~42%)组成,蒙脱石含量一般小于5%,区域分布上不具明显的差异性.但是,从珠江流域盆地到南海北部,高岭石含量持续降低,蒙脱石含量持续上升,伊利石含量也不断上升,伊利石化学指数递减,伊利石结晶度增强,这些特征都表明珠江流域盆地对南海北部黏土矿物的贡献主要是高岭石,其次是伊利石和绿泥石,基本不提供蒙脱石.研究认为,珠江对南海北部陆缘的黏土矿物贡献率最多为72%,而对北部陆坡的贡献率最多仅为15%.无论是冰期还是间冰期时期,高岭石都指示了珠江流域的机械侵蚀能力.
Clay minerals play an important role in the study of the evolution of the East Asian monsoon in the South China Sea in recent years because of their ability of tracking ocean current changes and revealing the contemporaneous climate change in the provenance area. As one of the important rivers for the import of terrigenous materials in the northern South China Sea, Has not carried out detailed clay mineralogy.Using the X-ray diffraction method, the clay mineral assemblages in the surface sediments of the Pearl River Basin (including the mainstream of the Pearl River, the tributaries and the Lingdingyang Bay of the Pearl River) have been systematically studied.The results show that, The clay mineral assemblages in the Pearl River Basin are mainly composed of kaolinite (35% -65%), chlorite (20% -35%) and illite (12% -42% However, from the Pearl River basin to the northern part of the South China Sea, the content of kaolinite continued to decrease, the content of montmorillonite continued to rise, the content of illite was also increased, the chemical index of illite decreased, the degree of illite crystallinity These characteristics indicate that the contribution of the Pearl River Basin to clay minerals in the northern South China Sea is mainly kaolinite, followed by illite and chlorite, and basically does not provide montmorillonite.The study suggests that the Pearl River on the South China Sea Department of clay minerals margin contribution rate of up to 72%, while the contribution rate to the northern slope of up to only 15% either glacial or interglacial period, kaolinite are indicative of the mechanical erosion of the Pearl River Basin.