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中国沙漠 ›› 2025, Vol. 45 ›› Issue (6): 83-92.DOI: 10.7522/j.issn.1000-694X.2025.00042

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共和盆地茫拉剖面沉积物粒度端元特征与末次盛冰期以来环境演化

胡梦珺1,2(), 白清竹1,2, 许澳康3(), 孟祥云1   

  1. 1.西北师范大学,地理与环境科学学院,甘肃 兰州 730070
    2.西北师范大学,甘肃省绿洲资源环境与可持续发展重点实验室,甘肃 兰州 730070
    3.西北大学 地质学系,陕西 西安 710069
  • 收稿日期:2025-02-28 修回日期:2025-04-10 出版日期:2025-11-20 发布日期:2025-11-26
  • 通讯作者: 许澳康
  • 作者简介:胡梦珺(1974—),女,甘肃庆阳人,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);国家自然科学基金项目(41161036);西北师范大学绿洲科学科研成果突破行动计划项目(NWNU-LZKX-202306)

Sediment end-member characteristics and paleoenvironment since the last glacial maximum in Mangla profile of Gonghe Basin

Mengjun Hu1,2(), Qingzhu Bai1,2, Aokang Xu3(), Xiangyun Meng1   

  1. 1.College of Geography and Environmental Science /, Northwest Normal University,Lanzhou 730070,China
    2.Key Laboratory of Resource Environment and Sustainable Development of Oasis, Northwest Normal University,Lanzhou 730070,China
    3.Department of Geology,Northwest University,Xi′an 710069,China
  • Received:2025-02-28 Revised:2025-04-10 Online:2025-11-20 Published:2025-11-26
  • Contact: Aokang Xu

摘要:

共和盆地出露的风成沉积较好地记录亚洲季风和西风环流的演化信息,是研究古气候环境的良好载体。本文对共和盆地茫拉剖面512 cm厚的风成沉积的粒度数据进行参数化端元分析,结合粒度敏感指标和色度指标阐释了各端元揭示的物源特征、环境意义及末次盛冰期以来共和盆地的环境演化过程,并进一步分析了其与季风环流系统的协同性。结果表明:剖面沉积物粒度组分可分解为3个端元:EM1为湿沉降的高空西风搬运的远源粉尘物质,间接反映区域干湿变化;EM2为低空风系作用下以悬移和跃移形式短距离搬运的中远源细颗粒沉积;EM3为蠕移或跃移形式短距离搬运的近源粗颗粒沉积。EM2与EM3指示相反,但共同反映冬季风的强弱。区域环境演化可划分为3个阶段:末次盛冰期阶段(22.27~17.59 ka BP),气候冷干,受控于西风环流;末次冰消期阶段(17.59~10 ka BP),气候冷干-温润,冷暖波动,夏季风和西风交替控制;中晚全新世阶段(8.49 ka BP以来),气候由温润向冷干发展,夏季风与西风此消彼长。

关键词: 端元分析, 风成沉积, 末次盛冰期, 共和盆地

Abstract:

The emerging aeolian sediment in Gonghe Basin can well record the evolution information of Asian monsoon and westerly circulation, which is a good carrier for studying paleoclimate environment. In this paper, the grain size data of aeolian sediment 512 cm thick in the Mangla profile of Gonghe Basin were analyzed by parametric end members. Combined with the grain size sensitivity index and chroma index, the characteristics of material sources and environmental significance of each end member and environmental evolution of Gonghe Basin since the last glacial maximum were explained, and the synergy with monsoon circulation system was further analyzed. The results indicate that: The grain size components of the sediments in the profile can be decomposed into three end members, EM1 is the distant dust material transported by the upper westerly wind of wet deposition, which indirectly reflects the regional dry and wet. EM2 is the meso-distant fine sediment transported in the form of suspension and saltation under the action of low-level wind system, and EM3 is the near-source coarse sediment transported in the form of creep or saltation, which indicates the strength of regional winter monsoon. Regional environmental evolution can be divided into three stages: Last glacial maximum (22.27-17.59 ka BP), the climate was cold and dry, controlled by westerly circulation; Last deglaciation period (17.59-10 ka BP), the climate was cold and moist, with cold and warm fluctuations, and there may be controlled by alternating summer monsoon and westerly circulation; Middle and late Holocene (8.49 ka BP to present), the climate changed from warm and moist to cold and dry, and the summer monsoon and westerly circulation were complementary.

Key words: end member analysis, aeolian sediment, last glacial maximum, Gonghe Basin

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