罗布泊盐湖晚更新世末期芒硝岩沉积及其古气候意义  

Late Pleistocene Mirabilite Deposition in the Lop Nur Saline Lake,Xinjiang,and its Paleoclimate Implications

作　　者：刘成林[1] 焦鹏程[1] 陈永志[1] 王弭力[1] 

机构地区：[1]中国地质科学院矿产资源所,北京100037

出　　处：《地球学报》2008年第4期397-404,共8页Acta Geoscientica Sinica

基　　金：地质调查项目(编号:200010300105);国家科技攻关305项目专题(编号:2001BA609A-07-15)联合资助

摘　　要：罗布泊位于新疆塔里木盆地的东端,可能是世界最大的单体(干)盐湖。罗布泊从中更新世开始进入盐湖演化阶段,直到晚更新世末以钙芒硝沉积为主,进入全新世出现石盐沉积。一些钻孔揭示在上更新统顶部出现一些芒硝岩薄层,对比研究,确认这些钻孔中的芒硝层属同一时期沉积产物。14C测年显示,芒硝层段年代从13.72～16.92ka,光释光测年结果为19.34～19.83ka,这些与末次冰期最盛期的年代(14～22ka)基本吻合,推断当时罗布泊年均气温在-2～-3℃。至全新世早期,随着短期干冷气候结束,罗布泊转为咸水湖环境,自全新世中期以来,转变为盐湖环境。The Lop Nur Saline Lake located in eastern Tarim basin of Xinjiang is probably the largest single saline lake in the world. Front middle Pleistocene, LOp Nur Lake evolved into a saline lake environment and glauberite crystallized from brine in the lake until the end of Pleistocene. In the Lop Nur Lake, halite crystallized only during Holocene. Drilling shows that thin layers of mirabilite rocks occur at the top of upper Pleistocene strata. A comparison of strata from drilling holes reveals that the mirabilite layers belong to the contemporaneous sediments. ^14C-dating shows that the ages of mirabilite layers are from 13.72 - 16.92 ka, basically consistent with the age （ 14 -22 ka） of the last maximum glacier activity. The authors infer that the annual average atmospheric temperature of Lop Nur area was - 2 - - 3℃at that time. The following conclusion has thus been drawn： the global cold event had impacts on chemical sedimentation of the saline lake; with the ending of a short cold period, the Lop Nur Saline Lake changed into a saline water lake in early Holloeene; since middle Holocene, the lake has converted into a salt lake with the deposition of large amounts of halite.

关 键 词：罗布泊 盐湖 更新世 芒硝岩 冷期气候 

分 类 号：P534.631[天文地球—第四纪地质学]