地学前缘 ›› 2021, Vol. 28 ›› Issue (2): 1-18.DOI: 10.13745/j.esf.sf.2020.9.7

• 测年方法 • 上一篇    下一篇

山地灾害沉积物的测年综述

赖忠平1(), 杨安娜2,3, 丛禄2,4, 刘维明2, 王昊5   

  1. 1.汕头大学 海洋科学研究院, 广东 汕头 515063
    2.中国科学院、 水利部成都山地灾害与环境研究所 中国科学院山地灾害与地表过程国家重点实验室, 四川 成都 610041
    3.西北师范大学 地理与环境科学学院, 甘肃 兰州 730070
    4.中国科学院 青海盐湖研究所 中国科学院盐湖资源与化学重点实验室, 青海 西宁 810008
    5.中国科学院 地理科学与资源研究所, 北京 100101
  • 收稿日期:2020-06-15 修回日期:2020-08-23 出版日期:2021-03-25 发布日期:2021-04-03
  • 作者简介:赖忠平(1968—),男,教授,博士生导师,主要从事第四纪地质和光释光年代学研究。E-mails: zhongping.lai@yahoo.com; zhongping_lai@stu.edu.cn
  • 基金资助:
    国家自然科学基金项目(91747207);国家自然科学基金项目(41771023);国家自然科学基金项目(41807448)

A review on the dating techniques for mountain hazards-induced sediments

LAI Zhongping1(), YANG Anna2,3, CONG Lu2,4, LIU Weiming2, WANG Hao5   

  1. 1. Institute of Marine Sciences, Shantou University, Shantou 515063, China
    2. CAS Key Laboratory of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
    3. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
    4. CAS Key Laboratory of Salt Lake Resource and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
    5. Institute of Geographic Sciences and Natural Resource Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2020-06-15 Revised:2020-08-23 Online:2021-03-25 Published:2021-04-03

摘要:

山地灾害事件发生的年代是理解其发育机制并作出预测的基础。在长时间尺度上,常用的测年方法有光释光、14C、宇宙成因核素和火山灰测年等,其中的关键是能否在剖面中寻找到合适的测年物质。短时间尺度的测年方法以树轮为主,辅以地衣测年。在山地灾害中,不仅灾害沉积本身,其相关沉积物对事件年代也具有指示意义。在实际应用中,根据测年材料的可获性来选择合适的测年方法,最好能结合多种方法对整个灾害沉积体系进行交叉测年,以增强结果的可靠性。野外采样既要满足灾害研究的需要,又要满足年代学的要求。因此建议在野外采样时,灾害和年代学研究人员共同现场讨论以确定最佳采样策略。随着山地灾害得到越来越多的关注,人们认识到仅依据测量记录和历史记录很难具备足够的数据来评估其频率和强度变化,因而,古灾害事件的测年必将得到越来越多的应用。

关键词: 山地灾害, 测年方法的选择, 野外采样策略

Abstract:

Chronology of mountain hazard events is the foundation for understanding hazard mechanisms and making hazard predictions. On the long timescale, the conventional dating methods include OSL, 14C, cosmogenic nuclides, tephrochronometry, etc.; on the short timescale, dendrochronology is normally used, supplemented by lichenometry. The selection of a specific technique depends on the availability of dating materials in the field. In order to enhance the reliability of dating results, cross-checking by different techniques is essential whenever dating materials are available. The field sampling should meet the age determination task for hazard events as well as the chronological requirements, thus researchers carrying out hazard and dating studies should collaborate routinely in the field during sample collection. We summarize here the routines and key points of related dating methods in order to provide some instructions for laboratory work and field trips. In particular, we emphasize the role of OSL and 14C techniques in dating mountain hazard sediments, as they are the most widely used dating methods at present. We suggest replicating dating results for critical sediment layers as an effective and practical way to assess the impact of OSL partial bleaching: If replication provides similar ages within error, the partial bleaching could be minor or negligible. OSL is ideal for dating dammed lake deposits which is the common recorder of mountain hazards. For 14C dating, the saturation age is mostly between 25-35 ka BP regardless of the dating materials, indicating that age falling into this range or beyond should be taken with caution.

Key words: mountain hazards, selection of dating techniques, sampling strategy in the field

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