基岩就地^14C测年及古地震潜在应用  

REVIEW ON IN-SITU COSMOGENIC ^(14)C DATING AND POTENTIAL APPLICATION IN PALEOEARTHQUAKE

作　　者：尹金辉[1] 杨雪[1] 郑勇刚[1] 

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029

出　　处：《地震地质》2016年第3期773-782,共10页Seismology and Geology

基　　金：国家自然科学基金(41572196);中国地震局地质研究所基本科研业务专项(IGCEA1417);中国地震局地震行业科研专项(201308001);地震动力学国家重点实验室自主研究课题(LED2013A08)共同资助

摘　　要：在陆地表面系统,^(14)C主要通过宇宙射线与大气和暴露岩石2个明显不同的介质发生核反应产生。在大气中生成的^(14)C,由此建立的^(14)C测年方法已广泛应用于考古学和古环境及地球各圈层的相互作用等方面的研究,推动了相关学科的发展;在基岩中产生的就地(in situ)^(14)C,随着加速器质谱计探测灵敏度的提升,就地^(14)C对地表过程的研究潜力开始得到广泛认可和关注,也已成为解决一些地球科学问题的重要方法。文中简要介绍了就地^(14)C的形成机制、产率值、实验方法的历史与现状以及使用宇宙成因核素研究基岩正断层活动性方面的最近进展。Over the last two decades,in-situ cosmogenic^（14）C dating has become an import tool in Quaternary geology and is recognized to geoscientists because of its potential to provide information on exposure age and process rate estimates for geomorphic studies. The in-situ cosmogenic radiocarbon has a relatively short half-life（ 5730 yr） and is substantially more sensitive than all the other cosmogenic nuclides used so far. It is therefore particularly useful to determine surface-exposure ages of Holocene landforms and quantify erosion rates in rapidly denuding landscapes during the past few tens of thousands of years. Moreover,in situ^（14）C is produced in quartz which is both highly resistant to weathering and common in nature,so it can be used in combination with other in-situ cosmogenic nuclides such as ^3He,^（10）Be,^（21）Ne,^（26）Al,and ^（36）Cl to constrain complex exposure histories involving burial and / or erosion occurring over the past 25 ka.The age and slip rate of Holocene normal fault have been undoubtedly a challenge for seismologists to be faced with as result from lack of appropriate late Quaternary sediment. Recently,the cosmogenic nuclides such as ^（36）Cl of preserved,seismically exhumed normal fault scarps were used to identify the last few major earthquakes and recover their ages and displacements through the modeling of the content of ^（36）Cl in the scarp rocks.This paper mainly summarizes the development of in-situ^（14）C dating,including its research history, production rate estimate, production mechanism, chemical behavior and experimental method. The potential application of in-situ^（14）C dating to recovering past earthquakes,their timing,and the regularity of their recurrence for preserved,seismically exhumed normal fault scarps is also introduced.

关 键 词：暴露面测年 宇宙成因核素 就地成因14C 正断层 

分 类 号：P597.1[天文地球—地球化学]