| 山地灾害沉积物的测年综述 |
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| 引用本文： | 赖忠平,杨安娜,丛禄,刘维明,王昊.山地灾害沉积物的测年综述[J].地学前缘,2021,28(2):1-18. |
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| 作者姓名： | 赖忠平 杨安娜 丛禄 刘维明 王昊 |
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| 作者单位： | 汕头大学海洋科学研究院,广东汕头515063;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;西北师范大学地理与环境科学学院,甘肃兰州730070;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;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;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;中国科学院地理科学与资源研究所,北京100101 |
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| 基金项目： | 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) |
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| 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。
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| 关 键 词： | 山地灾害 测年方法的选择 野外采样策略 |
| 收稿时间： | 2020-06-15 |
A review on the dating techniques for mountain hazards-induced sediments |
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| LAI Zhongping,YANG Anna,CONG Lu,LIU Weiming,WANG Hao.A review on the dating techniques for mountain hazards-induced sediments[J].Earth Science Frontiers,2021,28(2):1-18. |
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| Authors: | LAI Zhongping YANG Anna CONG Lu LIU Weiming WANG Hao |
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| 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. |
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| Keywords: | mountain hazards selection of dating techniques sampling strategy in the field |
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