中文摘要：

青海湖是我国最大的内陆封闭湖泊，位于青藏高原东北缘，处在亚洲季风和西风带两大气候系统的交汇带，对气候变化非常敏感，是研究全球变化的理想地区。青海湖地质历史时期的高湖面反映了当时与现代相比更湿润的气候。高湖面的年代及形成机制对研究青藏高原环境变化有重要意义。目前国际学术界关于青海湖末次间冰期以来高湖面出现的年代存在分歧：有的学者认为高湖面出现在氧同位素三阶段中晚期；而另有学者认为，高湖面出现在氧同位素五阶段，三阶段则没有高湖面。本文简要综述了半个多世纪以来关于青海湖末次间冰期以来湖面变化的研究结果，并应用光释光测年方法测定了青海湖东岸的湖滨和近岸湖相沉积物的年代，讨论了青海湖末次间冰期以来的湖面变化。本文还对青海湖的湖成阶地重新进行了划分，认为青海湖只有两级阶地；一级阶地拔湖～5—12m，形成于氧同位素3阶段早中期（60～40ka）及全新世；二级阶地拔湖～25—65m，形成于氧同位素5阶段。根据沉积物的沉积特征和光释光年代，认为青海湖的最高湖面出现在氧同位素5阶段，氧同位素3阶段早中期的湖面海拔高度只比全新世适宜期高～5m。全新世最高湖面出现在8～5ka，当时的湖面海拔为～3204m，高出现在湖面～10．6m（2010年3月湖面海拔为3193．4m）。

英文摘要：

Qinghai Lake, the largest closed-basin lake in China, lies in the northeastern part of the Qinghai-Tibetan Plateau. Controversies exist regarding to the timing of the high lake levels since the last interglaciation. Some reported that the high lake level appeared during late MIS 3 （-40--25 ka）, while others argued that the high lake level occured in MIS 5. In this paper, we reviewed briefly the previous research on the timing of high lake levels in Qinghai Lake, and then presented quartz optically stimulated luminescence dating of lacustrine deposits collected from two sections 23~41 m higher than the present lake level. We concluded that （1） only two terraces were identified in Qinghai Lake, and the elevation of the first terrace is ~3199--3206 m （~5-13 m above the present lake level）, the elevation of the second terrace is ~3219--3260 m （~25-65 m above the present lake level）; （2） the lacustrine sediments with elevation of 〉3220 m asl （26.6 m above the present lake level） were deposted during MIS 5; （3） the elevation of the lake level of early to middle MIS 3 （~60-40 ka） was just a few meters higher than that of the Holocene, which was ~15 m above the present lake level.