基岩区断层泥的物质组成、定年方法与地震断层弱化机制研究进展  

Advances in composition and dating methods of fault gouge and weakening mechanisms of earthquake faults in bedrock area

作　　者：徐先兵[1] 邓飞 王墩 罗锡宜 Xu Xianbing;Deng Fei;Wang Dun;Luo Xiyi(School of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China;College of Civil Engineering,Tongji University,Shanghai 200092,China;Foshan Geological Bureau of Guangdong Province,Foshan Guangdong 528000,China)

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074 [2]同济大学土木工程学院,上海200092 [3]广东省佛山地质局,广东佛山528000

出　　处：《地质科技通报》2022年第5期122-131,共10页Bulletin of Geological Science and Technology

基　　金：中国地质调查局项目(DD20190811);佛山市城市地质调查试点项目“三龙湾高端创新集聚区城市地质调查”(440600-202004-211001-0011);科技部重点研发计划(2018YFC0603500)。

摘　　要：断层泥作为脆性断层活动的产物,是厘定断层的变形特征、形成时代与弱化机制的重要研究对象,在构造地质和地震地质等研究中具有重要意义。因此,全面了解断层泥的研究与进展,有助于基岩区古地震的研究。在系统收集和分析国内外相关资料的基础上,全面介绍了断层泥的矿物组成、石英形貌特征、定年方法与地震断层弱化机制等方面的研究进展,以及断层泥在基岩区地震断层研究中的应用。断层泥主要由黏土矿物(蒙脱石、伊利石、高岭石以及绿泥石等)与围岩矿物的碎粉和碎砾(石英、长石、云母、方解石、白云石等)组成。断层泥中的石英、伊利石与方解石是限定断层活动期次和形成时代的主要测试对象。目前断层泥定年方法主要包括石英微形貌特征分析法、石英ESR和OSL定年法、伊利石K-Ar或^(40)Ar/^(39)Ar定年法和方解石U-Pb定年法。地震断层的弱化机制研究主要涉及断层泥中矿物细粒化与新矿物形成、岩石组构的发育、断层摩擦生热、熔体形成与热增压等方面。Fault gouges result from the sliding of brittle faults and can be used to determine the deformational characteristics,formation ages and weakening mechanisms of earthquake faults,which are of great significance for structural geology and earthquake geology.Therefore,the comprehensive understanding of the research findings and its advances in fault gouges will contribute to palaeoseismic investigations.On the basis of collected and absorbed data,we introduced comprehensive advances in the components of fault gouges,surface textures of quartz grains from fault gouges,dating methods of fault gouges and weakening mechanisms of earthquake faults.The fault gouge is mainly composed of clay minerals and powder and debris of wall rocks.The clay minerals mainly consist of montmorillonite,illite,kaolinite and chlorite.The powder and debris of wall rocks are mainly composed of quartz,feldspar,mica,calcite and dolomite.Quartz,illite and calcite selected from fault gouges could be used to distinguish the polysstages of faulting and date its formation ages.Geochronological methods include surface texture analysis of quartz grains,electron spin resonance(ESR)and optically stimulated luminescence(OSL)dating of quartz,K-Ar or ^(40)Ar/^(39)Ar dating of illite,and U-Pb dating of calcite.The weakening mechanisms of earthquake faults consist of the powder of minerals,the formation of new minerals and fabric development in fault gouges,and frictional heating,frictional melting and thermal pressurization after fault initialization.

关 键 词：地震断层 断层泥 物质组成 定年方法 断层弱化机制 

分 类 号：P546[天文地球—构造地质学]