第四纪冰碛暴露测年数据的分析策略与方法  

Analysis strategies and methods of surface exposure chronology data for Quaternary glaciation

作　　者：邱锦坤 王杰[1,2] QIU Jinkun;WANG Jie(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China;Shiyang River Basin Scientific Observing Station of Gansu Province,Lanzhou 730000,China)

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,甘肃兰州730000 [2]甘肃省石羊河流域野外科学观测研究站,甘肃兰州730000

出　　处：《冰川冻土》2024年第6期1908-1920,共13页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42371131,41971003);中央引导地方科技发展资金项目(23ZYQH0298)资助。

摘　　要：宇宙成因核素暴露测年是确定局地或区域第四纪冰川作用时代最主流和最重要的手段。强烈的地质地貌过程常造成样品预先暴露或不完全暴露,进而测年结果无法指示真实的冰川作用时代,其影响大时年代数据的离散程度甚至会非常高。学者们也先后提出了众多冰碛暴露测年的统计分析方法试图降低其不确定性,但厘定结果往往存在巨大差异,甚至成为第四纪冰川演化空间异时性及其驱动机制争议的根源。然而,无论国内还是国际上也都缺乏对这些方法的系统梳理和评估。为此,本文旨在梳理目前已有的分析策略与方法及其可能存在的局限性,提出更为完善的分析方法;并以雅鲁藏布江流域末次冰期以来已发表的冰碛10Be暴露测年数据为例,通过综合对比各种代表性分析方法间的差异,发现偏老年龄模式更具合理性,而本文提出P-PDE方法不仅可靠性高,精度也可满足千年时间尺度冰川演化序列建立的要求。此外,本文关于年代数据分析策略与方法的总结,对提升暴露定年在其他相关领域应用的可靠性和精度也具有重要的借鉴意义。Terrestrial cosmogenic nuclide(TCN) surface exposure dating is the most mainstream and significant methods of determining the age of local or regional Quaternary glaciation.Intense geomorphologic processes often cause samples to be affected by pre-exposure or incomplete exposure,which leads to dating results that are not indicative of the true age of glaciation,and the dispersion of the chronological data can even be very high when their influence is large.Several statistical analyses of moraine exposure dating have been proposed by scholars to reduce their influence.However,the results are often highly variable,which have even become the source of controversy over the asynchronous temporal and spatial patterns of glacial evolution and its driving mechanism.What's more,there is a lack of systematic review and assessment of these methods,both nationally and internationally.In this paper,we aim to review the existing analytical strategies and methods,as well as their possible limitations,and propose a better analytical method.The P-PDE method proposed in this paper is not only reliable,but also fulfils the requirements for establishing glacial evolution sequences on a millennial time scale.In addition,the summary of the strategies and methods of chronological data in this paper is also important for improving the reliability and accuracy of exposure dating for applications in other related fields.

关 键 词：冰碛 暴露测年 真实冰川作用时代 分析策略与方法 P-PDE 

分 类 号：P931.4[天文地球—自然地理学]