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中国沙漠 ›› 2023, Vol. 43 ›› Issue (2): 11-20.DOI: 10.7522/j.issn.1000-694X.2022.00103

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青藏高原东北部全新世常量元素地球化学特征及环境演变

胡梦珺(), 庄静, 孙文丽, 郑登友, 吉天琪, 许澳康   

  1. 西北师范大学 地理与环境科学学院,甘肃 兰州 730070
  • 收稿日期:2022-04-20 修回日期:2022-07-07 出版日期:2023-03-20 发布日期:2023-04-12
  • 作者简介:胡梦珺(1974—),女,甘肃庆阳人,博士,副教授,主要研究方向为寒旱区环境演变与元素地球化学。E-mail: lele200466@163.com
  • 基金资助:
    国家自然科学基金项目(41171018)

Geochemical characteristics of major elements and environmental evolution in the Holocene in the northeastern Tibetan Plateau

Mengjun Hu(), Jing Zhuang, Wenli Sun, Dengyou Zheng, Tianqi Ji, Aokang Xu   

  1. College of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,China
  • Received:2022-04-20 Revised:2022-07-07 Online:2023-03-20 Published:2023-04-12

摘要:

对青藏高原东北部风成砂-古土壤序列泽库剖面(ZK剖面)常量元素氧化物含量及其比值进行分析,结合14C测年,揭示其常量元素地球化学特征,探讨了青藏高原东北部全新世环境演变。结果表明:(1)剖面沉积物的化学组成以SiO2、Al2O3、CaO为主,其中SiO2和CaO的标准差较高,对气候变化较为敏感。(2)自剖面底部向上SiO2含量和残积系数呈现先减少后增加的趋势,高值指示冷干的气候意义,CaO含量和退碱系数则相反,高值指示温湿的气候意义。(3)9.4 ka BP以来青藏高原东北部的气候经历了由温湿向冷干的转变过程,可划分为9.4~4.2 ka BP气候温湿期和4.2 ka BP至今气候冷干期;其中在6.6~6.2 ka BP、2.4~2.0 ka BP和1.7~1.5 ka BP存在次一级的气候波动。

关键词: 常量元素, 全新世, 环境演变, 青藏高原东北部

Abstract:

Based on the analysis of the content and ratio of major element oxides from the aeolian sand-paleosoil sequence of Zeku profile in the northeastern Tibetan Plateau, combined with 14C dating, the geochemical characteristics of major elements of Zeku profile are revealed, and the environmental evolution in the Holocene in the northeastern Tibetan Plateau is discussed. The results show that: (1) The chemical composition of the sediment is mainly SiO2, Al2O3 and CaO, of which the standard deviation of SiO2 and CaO is higher and more sensitive to climate change. (2) From the bottom to the top of the profile, the contents of SiO2 and Ki decrease first and then increase, and the high values indicate a cold and dry climate, while the contents of CaO and W are opposite, and the high values indicate a warm and wet climate. (3) Since 9.4 ka BP, the climate of the northeastern Tibetan Plateau has undergone a transition from warm and wet to cold and dry, which can be divided into two stages: the warm and wet stage from 9.4 ka BP to 4.2 ka BP, and the cold and dry stage from 4.2 ka BP to now. There are sub-level climatic fluctuations in 6.6-6.2 ka BP, 2.4-2.0 ka BP and 1.7-1.5 ka BP.

Key words: major element, Holocene, environmental evolution, northeastern Tibetan Plateau

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