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干旱区地理 ›› 2021, Vol. 44 ›› Issue (6): 1623-1634.doi: 10.12118/j.issn.1000–6060.2021.06.11

• 地表过程研究 • 上一篇    下一篇

基于碎屑锆石年代学对黄土高原物源及其时空差异的理解与展望

牛燕宁1,2(),綦琳3,4,乔彦松3,4()   

  1. 1. 兰州理工大学土木工程学院,甘肃 兰州 730050
    2. 兰州大学地质科学与矿产资源学院,甘肃 兰州 730000
    3. 中国地质科学院地质力学研究所,北京 100081
    4. 新构造运动与地质灾害重点实验室,北京 100081
  • 收稿日期:2021-06-09 修回日期:2021-08-14 出版日期:2021-11-25 发布日期:2021-12-03
  • 通讯作者: 乔彦松
  • 作者简介:牛燕宁(1982-),女,博士研究生,主要从事第四纪气候与环境变化等方面的研究. E-mail: niuyn17@lzu.edu.cn
  • 基金资助:
    国家自然科学基金项目(41772383);国家自然科学基金项目(41907377);国家自然科学基金基础科学中心项目(41888101)

Understanding and prospects of provenance and time-spatial differences in the Loess Plateau based on detrital zircon chronology

NIU Yanning1,2(),QI Lin3,4,QIAO Yansong3,4()   

  1. 1. College of Civil Eengineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China
    2. School of Earth Sciences and Mineral Resources, Lanzhou University, Lanzhou 730000, Gansu, China
    3. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
    4. Key Laboratory of Neotectonic Movement and Geohazard, Beijing 100081, China
  • Received:2021-06-09 Revised:2021-08-14 Online:2021-11-25 Published:2021-12-03
  • Contact: Yansong QIAO

摘要:

中国黄土高原保存着全世界分布范围最广、厚度最大、连续性最好的风尘堆积,是第四纪非常有价值的陆相古气候古环境地质档案。半个多世纪以来,学界对风尘沉积的气候记录和黄土高原的成因进行了大量研究。然而,对黄土粉尘的确切来源以及物源历史是否存在时空变迁等问题尚存在广泛争议。通过对现有锆石年龄谱数据的统计分析,着重从黄土与周缘沙漠的亲缘关系、轨道年龄尺度和构造年龄尺度的角度着手,获得以下认识:(1) 在获得北方干旱区沙漠确切年代学信息的基础上,应用碎屑锆石U-Pb年龄谱法有望实现厘清黄土与风成沙之间物源亲疏关系的远景目标。(2) 现有数据识别出L1黄土的物源可能存在空间差异。(3) 支持冰期-间冰期的黄土物源未发生重大改变的观点。(4) 在构造时间尺度上,不同地区年龄谱表现出可能发生物源转移的时段明显重叠。(5) 有限的红黏土年龄谱数据显示物源的空间差异很可能在第四纪之前就已存在。鉴于目前的数据量还较少,有必要深入开展工作。应用该方法,可以在连续的长时间尺度下对黄土物源变化历史开展研究,并为将来在黄土高原开展多地区多剖面物源对比工作积累数据集。

关键词: 碎屑锆石U-Pb测年, 物源示踪, 时空差异, 黄土高原

Abstract:

The Loess Plateau of China preserves the most widely distributed, thickest, and continuous aeolian dust deposits in the world. It is a valuable geological archive of continental paleoclimate and paleoenvironment in the Quaternary. For more than half a century, several studies have been conducted on the climate records of aeolian dust deposition and the genesis of the Loess Plateau. However, studies have yet to determine the exact source of loess dust and verify whether a temporal-spatial change occurred in the provenance history. In this study, existing zircon age spectral data are statistically analyzed to explore the genetic relationship of loess and the surrounding desert with orbital and tectonic age scales. Results reveal the following: (1) the application of zircon U-Pb age spectral method based on the obtained exact chronological information of deserts in northern arid regions may clarify the provenance relationship between loess and aeolian sand. (2) available data indicate that the provenance of L1 loess may be spatially different. (3) confirmation that the provenance of loess in the glacial-interglacial period has not changed significantly. (4) On the tectonic timescale, the age spectra of different regions indicate that the periods of possible provenance transfer have an obvious overlap. (5) The limited age spectral data of red clays suggest that spatial differences in provenance probably existed before the Quaternary. However, current data are limited; thus, further related studies should be conducted. Using this method, the history of changes in loess provenance may be explored on a continuous long-term scale, and data sets may be obtained and used for future provenance comparisons of multiple locations and profiles in the Loess Plateau.

Key words: detrital zircon U-Pb dating, source tracing, time and space differences, Loess Plateau