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中国沙漠 ›› 2024, Vol. 44 ›› Issue (2): 109-120.DOI: 10.7522/j.issn.1000-694X.2023.00138

• • 上一篇    

敦煌雅丹地层易溶盐特征及其对沉积环境的指示意义

梁晓磊1(), 程志花2, 翟晓慧1(), 牛清河3, 张益明4, 李艳丽4   

  1. 1.太原师范学院,经济与管理学院,山西 晋中 030619
    2.太原师范学院,地理科学学院,山西 晋中 030619
    3.中国科学院西北生态环境资源研究院 敦煌戈壁荒漠研究站/甘肃省风沙灾害防治工程技术研究中心/沙漠与沙漠化重点实验室,甘肃 兰州 730000
    4.敦煌市雅丹景区服务中心,甘肃 敦煌 736200
  • 收稿日期:2023-09-07 修回日期:2023-10-07 出版日期:2024-03-20 发布日期:2024-03-19
  • 通讯作者: 翟晓慧
  • 作者简介:翟晓慧(E-mail: zhaixiaohui@lzb.ac.cn
    梁晓磊(1986—),男,山西忻州人,博士,副教授,主要从事风沙地貌研究。E-mail: liangxiaolei@tynu.edu.cn
  • 基金资助:
    国家自然科学基金青年科学基金项目(42001007);国家自然科学基金面上项目(42171016)

Soluble salt deposition of the Dunhuang yardang strata and its indication for sedimentary environment

Xiaolei Liang1(), Zhihua Cheng2, Xiaohui Zhai1(), Qinghe Niu3, Yiming Zhang4, Yanli Li4   

  1. 1.School of Economics and Management /, Taiyuan Normal University,Jinzhong 030619,Shanxi,China
    2.Institute of Geographical Science, Taiyuan Normal University,Jinzhong 030619,Shanxi,China
    3.Dunhuang Gobi and Desert Research Station / Gansu Center for Sand Hazard Reduction and Engineering and Technology / Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    4.Dunhuang Yardang Scenic Area Service Center,Dunhuang 736200,Gansu,China
  • Received:2023-09-07 Revised:2023-10-07 Online:2024-03-20 Published:2024-03-19
  • Contact: Xiaohui Zhai

摘要:

雅丹地层是雅丹地貌形成发育的物质基础,记录了沉积过程、环境演化、地貌格局等大量的地表过程信息,而沉积物理化分析则成为解读其关键信息的重要前提。易溶盐特征作为重要的环境代用指标对解读雅丹地层沉积演化过程具有重要指示意义。以敦煌雅丹地貌为研究对象,对其出露地层的易溶盐沉积特征、环境代用指标以及沉积环境演化等进行了深入探讨。结果表明:(1)敦煌雅丹地层沉积物优势离子以Mg2+-Na+-Ca2+-Cl--SO42-组合为特征,相应的离子类型主要包括Cl-Na型与SO4-Ca-Mg;(2)主要离子与总含盐量纵向旋回变化特征显著,以硫酸盐和氯化物盐交替演化为主,二者对雅丹易溶盐沉积具有决定性控制作用;(3)环境代用指标Mg2+/Ca2+、Cl-/SO42-等在雅丹环境变化研究中具有一定的局限性,表明雅丹地层并非完全由稳定的湖泊沉积发育而来;(4)雅丹地层是不同沉积环境和动力机制下形成的多种物质交替沉积的结果,主要包括静水湖泊、湖滨、河流、风成和冲积扇远端泥坪物质,其中湖滨、河流与风成沉积物的理化性质相近,难以有效区分,有待进一步深入研究。

关键词: 雅丹地层, 沉积物, 易溶盐, 主要离子, 沉积环境

Abstract:

The yardang strata is the material manifestation of the sedimentary system before the yardang landform developed. It records a large amount of surface process information such as sedimentation processes, environmental evolution, and landform patterns. The physical and chemical analysis of sediments has become an important prerequisite for interpreting its key information. As an important environmental proxy index, the characteristics of easily soluble salts have important significance in interpreting the sedimentary evolution process of the yardang Formation. This paper takes Dunhuang yardang landforms as the research object, and conducts an in-depth discussion on the soluble salt deposition characteristic, environmental proxy indicators and sedimentary environment evolution of its exposed strata. The results indicated that: (1) The dominant ions' composition of soluble salts in yardang sediments is characterized by the combination of Mg2+-Na+-Ca2+-Cl--SO42-, and the corresponding ion types mainly include Cl-Na type and SO4-Ca-Mg type. (2) The main ions and the total salt content in the studied profiles have significant vertical cycle variation characteristics, mainly dominated by the alternating changes of sulfate and chloride salts, both of which play a decisive role in controlling the deposition of yardang soluble salts. (3) Environmental proxies such as Mg2+/Ca2+ and Cl-/SO42- have certain limitations in the differentiating of yardang environmental changes, indicating that yardang strata were not entirely developed from stable lacustrine deposition. (4) The yardang formation is the result of alternate deposition of various materials formed under different sedimentary environments and dynamic mechanisms, which mainly includes stable lacustrine, lakefront, fluvial, aeolian and alluvial fan's mud flat materials. Among them, lakefront, fluvial and aeolian sediments have similar physical and chemical properties, making it difficult to distinguish in detail and need further study.

Key words: yardang strata, sediment, soluble salt, dominant ions, sedimentary environment

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