柴达木盆地大浪滩地区表层芒硝的形成时代及环境意义  

Forming Age of Surface Mirabilite in Dalangtan,Qaidam Basin and its Environmental Significance

作　　者：马妮娜[1,2,3] 郑绵平[1,2,3] 马志邦[4] 陈文西[1,2,3] 孔凡晶[1,2,3] 施林峰[1,2,3] 

机构地区：[1]国土资源部盐湖资源与环境重点实验室,北京100037 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质科学院盐湖与热水资源研究发展中心,北京100037 [4]中国科学院新生代地质与环境重点实验室,中国科学院地质与地球物理研究所,北京100029

出　　处：《地质学报》2011年第3期433-444,共12页Acta Geologica Sinica

基　　金：矿产资源研究所基本科研业务费(编号K0916);中国地质调查局项目(编号1212010511901、121201018057)资助的成果

摘　　要：通过对柴达木盆地大浪滩地区的两次实地勘查,发现小梁山多处可见芒硝—碳酸盐粘土互层的露头,选取了完整沉积的D26剖面进行研究。比较盐湖学的研究表明,芒硝是典型的冷相盐类矿物;而碳酸盐粘土和石膏则反映了相对温凉和盐湖淡化的环境。本文通过对芒硝—碳酸盐粘土互层的矿物鉴定,石膏的铀系不平衡法定年,以及结合碳酸盐粘土的碳氧同位素分析,首次揭示大浪滩地区在倒数第二次冰期(MIS6阶段)前后经历了温凉半干燥期(>195.1kaBP)→寒冷干燥期(195.1～169.9kaBP)→温凉半干燥期(169.9kaBP)→温凉—寒冷交替时期(169.9～118kaBP)→温凉半干燥期(118kaBP)的气候演变序列。经与黄土剖面,深海氧同位素和区域研究资料的对比表明,自中晚更新世以来,大浪滩地区不仅受到区域地质活动的影响,也与全球的气候变化同步响应。Based on two field survey in the Dalangtan area of Qaidam Basin,many outcrops of mirabilite and carbonate clay interlayers were found in Xiaoliangshan.The well D26 section was selected for research in this study.The comparative salinology study shows that mirabilite is a typical cold saline mineral and carbonate clay and gypsum is indicative of relative cool and semiarid conditions.Using mineralogical identification of mirabilite and carbonate clay interbeds,gypsum U-Th datings,and carbon and oxygen isotopic analysis of carbonate clay,this study firstly reveals that the Dalangtan region underwent five climate stages around penultimate glaciation（MIS 6）：relative cool-semiarid stage（195.1 ka BP）,frigid-arid stage（195.1 ~ 169.9 ka BP）,relative cool-semiarid stage（about 169.9 ka BP）,chilly-cold fluctuating stage（169.9 ka BP ~ 118 ka BP）,and relative cool-semiarid stage（118 ka BP）.Comparative study with loess section and marine oxygen isotope and regional research data suggests that since Middle and Late Pleistocene,the Dalangtan region was not only uplifted by activities of regional geology,but also response to global climate change.

关 键 词：柴达木盆地 大浪滩 小梁山 芒硝—碳酸盐粘土互层 倒数第二次冰期(MIS6) 气候变化 

分 类 号：P544.4[天文地球—构造地质学] P571[天文地球—地质学]