青海湖湖东风成剖面化学元素特征及其环境指示意义

通过对青海湖湖东沙地风成沉积剖面化学元素特征的分析，结合光释光测年结果，并和已有研究进行对比，探讨了青海湖区12.5 ka BP以来的气候环境变化过程，将其划分为5个阶段：12.5 ka BP前气候寒冷干燥，青海湖应处于冰川消退的寒冷期，风沙活动强烈；12.5~11.9 ka BP气候向暖湿转变，其中12.2~11.9 ka BP发生一次寒冷事件，对应于新仙女木事件；11.9~8.0 ka BP气候冷暖波动频繁，期间出现了3次寒冷事件；8.0~2.6 ka BP是一个持续时间较长的温暖湿润期；2.6 ka BP至今，气候以干冷为主，与现代气候相近。

Geochemical Features and Palaeoenvironmental Indications ofAeolian Sediments on the East of Qinghai Lake

As the largest inland lake of China, along with its unique landscape and geographical location, Qinghai Lake has got much attention of the researchers for a long time. The precursors have done substantive researches by using the lake sediments, which have deepened our understanding on the climate changes in the region. Although sand dunes and loess sediments are widely distributed around the lake, so far the researches on geochemical elements from aeolian sediment have been less reported. Based on the systematic sampling from aeolian sediments at sandy land on the east of Qinghai Lake, through analysis on 7 main geochemical elements, combining with optically stimulated luminescence (OSL) dating results and the previous researches, we discussed climate changes in Qinghai Lake area since 12.5 ka BP and came to the following conclusions: (1) Before 12.5 ka BP, the climate there was dry and cold accompanied with strong wind-sand activities. (2) In 12.5-11.9 ka BP, the climate turned to warm and wet. However, there was an abrupt climate cooling event during 12.2-11.9 ka BP, which likely responded to the Younger Dryas event. (3) In 11.9-8.0 ka BP, the climate fluctuated significantly and frequently from warm to cold and this period witnessed 3 cooling events. (4) In 8.0-2.6 ka BP, the climate was warm and humid. (5) Since 2.6 ka BP, similar to the modern climate, the main feature of the climate was dry and cold.