Forming Age of Surface Mirabilite in Dalangtan,Qaidam Basin and its Environmental Significance
Forming Age of Surface Mirabilite in Dalangtan,Qaidam Basin and its Environmental Significance
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发表时间：
2011
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通讯作者：
M. Nina
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作者：
M. Nina
在柴达木盆地大浪滩地区两次野外考察的基础上，发现小凉山地区存在大量芒硝和碳酸盐粘土夹层露头。本研究选取D26井为研究对象。对比盐渍学研究表明，芒硝是典型的冷盐矿物，碳酸盐粘土和石膏指示相对凉爽和半干旱条件。利用芒硝和碳酸盐粘土夹层的矿物学鉴定、石膏U-Th定年和碳酸盐粘土的碳氧同位素分析，首次揭示了大浪滩地区在倒数末次冰期(MIS6)前后经历了5个气候阶段：相对冷-半干旱阶段(195.1 ka BP)，寒旱阶段(195.1~169.9 ka BP)、相对冷半干旱阶段(约169.9 ka BP)、冷冷波动阶段(169.9 ka BP~118ka BP)和相对冷半干旱阶段(118ka BP)。与黄土剖面、海洋氧同位素和区域研究资料的对比研究表明，大浪滩地区自中、晚更新世以来，不仅受到区域地质活动的抬升，而且还响应了全球气候变化。
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.