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南海西部越南岸外MD05-2901孔晚第四纪450ka以来黏土矿物和氧同位素的高分辨率分析表明,伊利石、绿泥石和高岭石含量表现出明显的冰期-间冰期旋回变化,而蒙脱石含量呈现频率更高的周期性变化.物源分析表明,MD05-2901孔黏土矿物中的蒙脱石主要由巽他陆架及其主要源区印度尼西亚岛弧提供,伊利石和绿泥石主要由湄公河和红河提供,而高岭石则主要由珠江提供.高岭石/(伊利石+绿泥石)比值的变化显示强烈的100ka偏心率周期,指示了冰盖驱动的冬季风演化;而蒙脱石含量的高频变化除了具有冰盖驱动的41ka斜率周期以外,还具有23和19ka岁差周期、以及13ka半岁差周期,指示了热带驱动的夏季风演化.东亚冬季风的演化基本上与冰期-间冰期旋回一致,冰期时强盛,间冰期时明显减弱;而夏季风的演化则与北半球低纬夏季日射量吻合较好,日射量高时强盛,低时减弱.研究认为,高纬冰盖和低纬热带分别驱动了晚第四纪东亚冬季风和夏季风的演化,反映了东亚季风演化的双重和独立的驱动机制.
High-resolution analysis of clay minerals and oxygen isotopes since the late Quaternary of the Middle Mouth of MD05-2901 in the western South China Sea shows that the contents of illite, chlorite and kaolinite show obvious glacial-interglacial cycles, The results show that the montmorillonite in the MD05-2901 clay mineral is mainly provided by the Indonesian island arc of the 巽 He shelf and its main source region and the illite and chlorite mainly consist of Mekong and Red Rivers, while kaolinite is mainly supplied by the Pearl River.The changes in kaolinite / (illite + chlorite) ratios show a strong 100 ka eccentricity cycle, indicating ice-covered winter monsoon evolution, In addition to the ice sheet-driven 41ka slope cycle, the high-frequency variations in the trifoliate content also have the 23 and 19ka precession cycles and the 13ka pre-precession cycle, indicating a tropical-driven summer monsoon evolution.The evolution of the East Asian winter monsoon is essentially consistent with glacial - the interglacial cycles are consistent, the glacial period is strong, and the interglacial period is obviously weakened; while the summer monsoon evolution is in good agreement with that of the northern hemisphere in summer at low latitudes, The high latitudes and low latitudes respectively drive the evolution of the late Quaternary East Asian monsoon and summer monsoon, reflecting the dual and independent driving mechanism of the East Asian monsoon evolution.