【摘要】 通过对黄河源区的钻孔、自然露头的研究, 建立了黄河源区的第四纪地层层序。第四纪地层可划分为下更新统、中更新统、上更新统和全新统。下更新统为河湖相沉积; 中更新统主要有湖积物、冰碛物和冰水沉积物; 上更新统主要有湖积物、冰碛物、冰水沉积物、洪积物和河流沉积物; 全新统主要由河流沉积物、洪积物和湖积物构成。黄河源区的冰期可划分为3期, 即末次冰期、倒数第二次冰期、倒数第三次冰期, 末次冰期又可分为2个冰阶。黄河源区的湖泊演化可划分为早更新世、中更新世和晚更新世—全新世3个阶段: 早更新世的湖泊范围小; 中更新世的湖泊范围明显扩大, 在位置上也较早更新世的湖泊南移; 晚更新世的湖泊经历了两次的扩张—收缩变化, 到了全新世, 除现今还发育的几个湖泊外, 大多数地区的湖水已退出, 基本上转变为河流环境。在晚更新世末期到全新世初期, 封闭黄河源区的多石峡被切开, 湖水外泄, 现今的黄河形成了, 同时发生了袭夺长江水系的水流。更多还原

【Abstract】 The Quaternary sequence of the source area of the Yellow River is set up on the basis of research on the natural exposures and cores, and it consists of the Lower Pleistocene, Middle Pleistocene, Upper Pleistocene and Holocene The Lower Pleistocene is alluvial and lacustrine sediments; the Middle Pleistocene is composed of lacustrine, glacial and fluvioglacial sediments; the Upper Pleistocene consists of lacustrine, glacial, fluvioglacial, pluvial and alluvial sediments; and the Holocene is made of alluvial, pluvial and lacustrine sediments Three glacial periods in the source area since the Middle Pleistocene are recognized, which are the last glacial period, the reciprocal second glacial period (late Middle Pleistocene) and the reciprocal third glacial period (early Middle Pleistocene) During the reciprocal third glacial period an ice sheet in the source area may be formed The last glacial period is divided into two stadial stages with an interstadial stage Evolution of lakes of the source area during the Quaternary went through three stages The first stage is the Early Pleistocene, in which numbers and areas of lakes largely decreased compared to those of the Pliocene and lakes developed only along the south foreland of the Buqing Shan The second stage, lake expending stage, is the Middle Pleistocene Lake cover at that time was ten times in area more than that of the Early Pleistocene The last stage is the Late Pleistocene and the Holocene and is recognized two lake expanding periods with two lake shrinking periods The Yellow River in the source area occurred from the last Late Pleistocene to the earliest Holocene, and meanwhile the Yellow River captured the current of the upper reaches of the Yangtze River更多还原