盐池位于祁连山北麓的河西走廊中段,是研究长时间尺度亚洲夏季风影响区北部边界变化的关键区域。现代气候学证据显示,亚洲夏季风的水汽输送限于祁连山东部地区,但是在全新世长尺度气候变化的背景下,夏季风西北边界是否会南北向移动是一个关键的科学问题。本研究对盐池古湖泊沉积物进行了孢粉浓缩物AMS14C测年,并分析了岩性、粒度、矿物及地球化学等指标。年代结果显示剖面下部湖相沉积层主要形成于晚冰期和早全新世期间,配合指标研究,该时期盐池沉积物体现了湖泊扩张的特征;剖面中部湖相沉积层主要形成于早、中全新世过渡时期,该段年代序列混乱,且普遍偏老,与之对应的指标结果显示湖泊开始退缩。湖泊退缩过程中,湖泊边缘附近水动力作用较强,导致再搬运及再沉积作用明显,从而使得年代结果较老且混乱。中全新世以来盐池古湖泊退缩明显,沉积速率较低,以泥沼相沉积为主。盐池晚冰期以来湖泊演化过程与青藏高原区和典型季风区的古气候记录具有一致性,整体表现为晚冰期及早全新世湖泊扩张,中、晚全新世期间湖泊退缩明显,这种变化模式与西风区湖泊演化存在差异,显示了千年尺度亚洲夏季风对该区域的影响,证明了夏季风北部边界摆动的事实。 Located in the middle of the Hexi Corridor at the northern foot of the Qilian Mountains, Yanchi is a key area for studying the changes in the northern boundary of the Asian summer monsoon impact region on a long-term scale. Modern climatological evidence shows that the transport of water vapor from the Asian summer monsoon is limited to the eastern part of the Qilian Mountains. However, whether the northwesterly movement of the northwest monsoon will move in the context of long-term climate change during the Holocene is a key scientific issue. In this study, AMS14C dating of the pollen concentration of the ancient salt lake sediments was carried out, and the lithology, grain size, mineralogy and geochemistry index were analyzed. The results of the age show that the lacustrine sediments in the lower part of the section were mainly formed during the late glacial and early Holocene, with the study of the co-ordination index. During this period, the salt pond sediments showed the features of lake expansion. The lacustrine sediments mainly formed in the early and middle Holocene, During the transitional period, the chronology of this period was chaotic and generally over-aged. The corresponding index results showed that the lake started to shrink. During the process of retreating the lake, the strong hydrodynamic interaction near the edge of the lake resulted in significant redelivery and redeposition, which made the results of the age older and confused. Since the Middle Holocene, the Yanchi ancient lake receded obviously, with a relatively low sedimentation rate, dominated by mud and mud sediments. The lacustrine evolution of Yanchi since the late glacial period is consistent with the paleoclimate records of the Qinghai-Tibet Plateau and the typical monsoon region. The whole record shows the lacustrine expanse in the Late Glacial and Early Holocene, and the lake retreat during the Mid-Late Holocene. There are differences in the evolution of lakes in the area, showing the impact of the Asian monsoon on the millennium scale and the fact that the northern boundary of the summer monsoon swings.