黄河源地区晚更新世湖泛事件及其意义

通过青海玛多湖相地层剖面沉积特征，结合ESR样品年代测试结果，分析认为黄河源地区在13万年左右的晚更新世时期发生过湖泛事件。湖泛时期，玛多"四姐妹湖"相互连通，形成一个面积巨大的湖泊，约是现今"四姐妹湖"总面积的4.1倍。玛多地区此次湖泛事件与深海氧同位素MIS 6（Marine isotope stages 6）向MIS 5（Marine isotope stages 5）转变时期相对应，显示出青藏高原气候变化与全球气候变化密切相关，然而黄河源地区湖相地层对全球气候变化反应更敏感，记录的气候转换时间早于其他地区。玛多剖面湖相地层剖面沉积物的粒度、碳酸盐、磁化率分析表明，在132±10~128±12 ka年间，黄河源地区湖相沉积可分为9个阶段，表明青藏高原在MIS 6向MIS 5转变时期的气候变化是一个波动上升过程。13万年左右，黄河源地区大面积的湖相地层结束沉积，认为由于青藏高原共和运动，下游的多石峡被切开，湖水突然外泄所形成。 

Pan-lake during the late Pleistocene in the source area of the Yellow River and its significance

According to the sedimentary characteristics and the results of ESR dating of the lacustrine strata profile in Maduo County, Qinghai Province, the pan-lake event had occurred in the source area of the Yellow River during the late Pleistocene period at about 130 kaB.P.. During the pan-lake period, the four lakes in Maduo County connected with each other, and formed one huge lake whose area was 4.1 times bigger than the total area of the present four lakes. The pan-lake event in the Maduo area coincided with the transition of deep sea oxygen isotope from MIS 6 to MIS 5, which shows that the climate change on the Qinghai-Tibet Plateau is closely related to the global climate change. As the lacustrine strata in the source area of the Yellow River were more sensitive to the global climate change, it recorded the climate change earlier than other areas did. The analysis of the grain size, carbonate and magnetic susceptibility of the sediments in the Maduo lacustrine strata profile shows 9 stages of the lacustrine sediments during the period of 132±10~128±12 ka, indicating a fluctuating and rising process of climate change on the Qinghai-Tibet Plateau in transition from MIS 6 to MIS 5. A large area of lacustrine sedimentation in the source area of the Yellow River ended at about 130 kaB.P. This may be the result of the regional tectonic activities of Gonghe Movement which cut through the Duoshixia gorge in the lower reaches, causing a suddenly leak out of the lake water.