Major-element geochemistry from two Cores MD05-2899 and MD05-2901 off central Vietnam in the lower continental slope of the western South China Sea is investigated to reconstruct a history of terrigenous sediment variations and East Asian monsoon evolution during the last glacial-interglacial cycle. The results suggest that the Pearl River can play a more important role in contributing terrigenous sediments to the western South China Sea than the Red River in the north, while the Mekong River can transport more terrigenous sediments to the region than the Sunda shelf and the Indonesian islands in the south. The Pearl River provides terrigenous sediments with higher Al₂O₃, but lower K₂O, MgO, and Fe₂O₃ (Total Fe) than the Mekong River. K₂O/Al₂O₃, MgO/Al₂O₃, and Fe₂O₃/Al₂O₃ ratios are then used as proxies to trace terrigenous sediment variations in the western South China Sea. Higher K₂O/Al₂O₃, MgO/Al₂O₃, and Fe₂O₃/Al₂O₃ ratios indicate strengthened terrigenous sediments input from the southern source and lower the ratios suggest increased terrigenous sediments received from the northern source. These ratios show a glacial-interglacial cycle over the past 130 ka, implying a close relationship with the East Asian monsoon evolution. Northward surface currents forced by strengthened summer monsoon during interglacial periods bring relatively higher amounts of terrigenous sediments from the southern source to the western South China Sea, while relatively higher amounts of terrigenous sediments from the northern source are transported to the western South China Sea by southward surface currents in strengthened winter monsoon during glacial periods. Our study indicates that the terrigenous sediment variations in the western South China Sea are significantly controlled by surface currents under the strong influence of the East Asian monsoon evolution during the last glacial-interglacial cycle.

研究了南海西部下部大陆斜坡上越南中部两个岩心MD05-2899和MD05-2901的主要元素地球化学，以重建末次冰河-冰期旋回期间陆源性沉积物变化和东亚季风演变的历史。结果表明，与北部的红河相比，珠江在南海西部贡献陆源性沉积物方面起着更重要的作用，而湄公河在向该地区输送陆源性沉积物方面要比da达河架和印度尼西亚的陆运性更多。南部的岛屿。珠江提供的陆源沉积物中Al ₂ O ₃较高，但K ₂ O，MgO和Fe ₂ O ₃较低。（总铁）比湄公河大。然后，将K ₂ O / Al ₂ O ₃，MgO / Al ₂ O ₃和Fe ₂ O ₃ / Al ₂ O _3的比率用作代表，以追踪南海西部的陆源性沉积物变化。较高的K ₂ O / Al ₂ O ₃，MgO / Al ₂ O ₃和Fe ₂ O ₃ / Al ₂ O ₃比率表明来自南部源的陆源沉积物输入增加，比率较低则表明来自北部源的陆源沉积物输入增加。这些比率显示了过去130 ka的冰期-冰期循环，这表明它与东亚季风的演变有着密切的关系。夏季风在冰期间增强，迫使北向地表水流将相对大量的陆源沉积物从南部源带入南海西部，同时将相对较高量的陆源沉积物从南源向南输送至南海西部冰川期冬季季风增强时的地表水流。