吉兰泰盐湖的形成及指示的环境意义  

Formation of Jilantai Salt Lake and Its Environmental Significance

作　　者：春喜[1] 王宗礼[2] 夏敦胜[3] 赵辉[3] 

机构地区：[1]内蒙古师范大学地理科学学院 [2]兰州大学西部环境教育部重点实验室,甘肃兰州730000 [3]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《盐湖研究》2008年第3期11-18,共8页Journal of Salt Lake Research

基　　金：中国科学技术部国际合作项目(2002CB714001);国家自然科学基金项目(40761028)资助

摘　　要：选择位于季风边缘区的吉兰泰盐湖为研究对象,利用OSL和14C测年手段重建湖面波动历史,探讨盐湖形成年代与环境变化过程。通过大范围的野外调查发现,在该湖泊南部地区发育高于现代干盐滩9 m的湖滨砂沉积,上覆风成砂沉积,其中湖滨沉积物的OSL年代为6.7 ka BP前后,表明当时该湖泊处于浅水状态,此后湖水经历了快速的下降过程。对于盐湖中心剖面点盐层之下粘土层的14C测年显示,在5 500 aBP以来,集聚大量的石膏、芒硝和石盐等蒸发盐类,该湖泊进入成盐期。通过区域对比发现,吉兰泰湖面快速下降阶段与季风边缘区中全新世干旱事件发生时间相对应。研究认为,吉兰泰盐类矿物的开始沉积,反映了中全新世阿拉善高原区域环境的突然变化,可能指示着5.5 Cal ka BP前后干旱事件的发生。The paper selects Jilantai Salt Lake which is suited on the transition belt of Eastern Asia moonsoon region in northern China as a study area, and reconstructs paleolake level variations and age of salt lake evolution by OSL and ^14C dating method. By large scale in-site investigations and OSL dating on shoreline sediment, all the dating results imply that the shoreline 6.7 ka BP in mid Holocene is 9 meters higher than that of today around Jilantai Lake. It is shown that the lake level dropped at that time and the lake had decreased and shrank since then. The ^14C age of the claypan at the bottom of salt layer in the center of the lake is 5.5 Cal ka BP, which shows that the salt minerals began to precipitate gypsum,Glauber＇ s salt and rock salt. With the drought becoming intense, the Jilantai salt lake stepped into the stage of a salt lake. Regional comparisons suggest that rapid declining period of Jilantai Salt lake is coincident with mid Holocene dry event. The study believes that beginning of Jilantal salts mineral deposition had reflected abrupt environmental changes in Alasha Plateau during mid Holocene. It possibly implyed that dry event had happened 5.5 Cal ka BP.

关 键 词：吉兰泰盐湖 干旱事件 环境变化 

分 类 号：P343.3[天文地球—水文科学]