芒硝的铀系定年：以柴达木盆地察汗斯拉图盐湖为例

Saline lake deposition have preserved some valuable materials of saline stage, which is lost by lacustrine sediments. As a late products of saline stage in salt lake, mirabilite has its unique research value to response to extreme arid climate. But the studies on mirabilite dating are several, which restricted mirabilite contributing to studies on extreme arid climate. This project aims to select mirabilite layers in Chahansilatu salt lake as research object, and try to set up a new U-series dating method of mirabilite and pretreatment process of samples. We will mutually calibrate U-series dating from mirabilite and other salt minerals with OSL data from the same profile sand samples; and then set up a reliable time sequence of salt minerals in Chahansilatu. Also we want to discuss the indication of mirabilite and its mineral assemblages to extreme arid climate in Chahansilatu salt lake.

盐湖沉积保存了一般湖沼相所缺失的咸化阶段的宝贵资料。芒硝作为盐湖咸化阶段的后期产物，在反映极端干旱气候条件方面也有着其独特的研究价值。但是目前有关芒硝定年的研究工作开展极少，制约了其对极端干旱气候研究的贡献。本项目拟选择察汗斯拉图地区的芒硝层作为研究对象，尝试建立芒硝矿物的铀系年龄测试方法及前处理流程；将芒硝等盐类矿物的铀系年龄结果与同剖面的光释光（OSL）年龄数据进行交叉检验，建立该研究区盐类矿物的可靠可信的年代序列；并且探讨芒硝及其矿物组合对察汗斯拉图地区极端干旱气候的指示意义。