郭海超^1,2,3,,
陈炽皓^1,2,3,
白艳^1,2,,,
方小敏^1,2,3,
张伟林^1,2
1. 中国科学院青藏高原地球科学卓越创新中心, 北京 100101
2. 中国科学院青藏高原研究所, 大陆碰撞与高原隆升重点实验室, 北京 100101
3. 中国科学院大学, 北京 100049

基金项目: 国家自然科学基金面上项目（批准号：41620104002、41571014和41371022）资助


详细信息

作者简介: 郭海超, 男, 27岁, 硕士研究生, 自然地理专业, E-mail:guohaichao@itpcas.ac.cn

通讯作者: 白艳, E-mail:baiyan06@itpcas.ac.cn

中图分类号: P593;P534.62⁺1

收稿日期:2017-09-25
修回日期:2017-11-15
刊出日期:2018-01-30

Paleoenvironmental evolution of the Xining Basin, NE Tibetan Plateau during mid-Miocene: Revealed by GDGTs

Guo Haichao^1,2,3,,
Chen Chihao^1,2,3,
Bai Yan^1,2,,,
Fang Xiaomin^1,2,3,
Zhang Weilin^1,2
1. CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101
2. Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101
3. University of Chinese Academy of Sciences, Beijing 100049


More Information

Corresponding author: Bai Yan,E-mail:baiyan06@itpcas.ac.cn

MSC: P593;P534.62⁺1

--> Received Date: 25 September 2017
Revised Date: 15 November 2017
Publish Date: 30 January 2018


摘要
摘要:西宁盆地关家山剖面微生物细胞膜脂的生物标志化合物甘油二烷基甘油四醚类脂物（Glycerol Dialkyl Glycerol Tetraethers，简称GDGTs）古温度指标MAT_mr记录了从16.8 Ma到13.4 Ma的持续降温过程（下降约5.1℃），与全球深海氧同位素记录的中中新世气候适宜期（MMCO）及其后的中中新世气候转型（MMCT）事件一致，揭示了西宁盆地古温度在此期间受全球温度变化控制。其环化参数CBT'重建的古pH值（CBT'-pH）平均为6.56±0.50，且80%样点的干旱指标R_i/b（古菌类异戊二烯型isoprenoid GDGTs（简称iGDGTs）与细菌支链型branched GDGTs（简称bGDGTs）相对含量比值）小于0.5，表明西宁盆地在此期间整体上处于较为湿润的环境，但是在14.0 Ma和14.8 Ma，R_i/b值记录了两次干旱事件。总之，虽然在古温度绝对值计算等问题上仍存在一定困难，GDGTs展现了在西宁盆地乃至青藏高原东北部在新近系甚至更老地层中应用的潜力。
关键词: GDGTs/
西宁盆地/
中中新世/
古温度/
古气候

Abstract:The MAT_mr records of Glycerol Dialkyl Glycerol Tetraether lipids (GDGTs) from Guanjiashan section (36°40.55'N, 101°50.24'E), Xining Basin, NE Tibetan Plateau, suggest the continuous cooling between 16.8 Ma and 13.4 Ma (droping in temperature about 5.1℃). Our result is consistent with the climatic events responding to Middle Miocene Climate Optimum (MMCO)and Middle Miocene Climate Transition (MMCT)recorded by global deep-sea oxygen isotope records. Thus, it reveals that MAT_mr were controlled by global temperature change during this period. The mean value of CBT'-derived paleo-pH (CBT'-pH)values is 6.56±0.50, and the abundances of bGDGTs (branched GDGTs)relative to that of archaeal isoprenoidal (iso)GDGTs (R_i/b, as a drought proxy in Chinese soils)for 80% samples are less than 0.5, together indicating relatively humid in that period as a whole in the Xining Basin. But two drought events were recorded by R_i/b values in 14.0 Ma and 14.8 Ma. Although it's difficult to estimate the absolute paleo-temperature at present, GDGTs have important potentiality to reconstruct paleo-temperature of Xining Basin, and so far as to NE Tibetan Plateau since Neogene and even older sediments.
Key words:GDGTs/
Xining Basin/
mid-Miocene/
paleo-temperature/
paleoclimate



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