重结晶碳酸盐在碳酸盐岩区基岩断层定年中的应用--以广西那坡断裂北段R剪切断层为例  

APPLICATION OF RECRYSTALLIZED CARBONATES TO THE DATING OF BEDROCK FAULTS IN CARBONATE ROCK AREA--A CASE STUDY ON THE R-SHEAR FAULT OF THE NORTHERN SECTION OF THE NAPO FAULT SYSTEM

作　　者：姬昊 刘春茹[1] 张沛全 李冰溯 聂冠军 魏传义[1] 尹功明[1] JI Hao;LIU Chun-ru;ZHANG Pei-quan;LI Bing-su;NIE Guan-jun;WEI Chuan-yi;YIN Gong-ming(State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China;Earthquake Agency of Guangxi Zhuang Autonomous Region,Nanning 530022,China)

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 [2]广西壮族自治区地震局,南宁530022

出　　处：《地震地质》2022年第5期1142-1155,共14页Seismology and Geology

基　　金：广西壮族自治区地震科技星火计划项目(XH20045);中国地震局地质研究所基本科研业务专项(IGCEA1908,IGCEA2015)共同资助。

摘　　要：在缺乏第四纪沉积物覆盖的碳酸盐岩基岩区,难以确定断层的第四纪活动历史。碳酸盐岩基岩区断层活动往往会在断层面上形成重结晶碳酸盐,这为利用ESR方法研究此类断层的第四纪活动历史提供了物质基础。文中采集了那坡断裂系北段一条R剪切断层基岩面的3个重结晶碳酸盐样品,并开展ESR测年研究。结果表明,该断层的活动时代大致为距今0.2Ma,根据里德尔剪切模型推测,那坡断裂的主干断层可能发生过晚于距今0.2Ma的构造活动;同时,碳酸盐岩基岩区断层活动产生的重结晶碳酸盐作为直接记录断层活动信息的测年材料,具有广阔的应用前景。The history of fault activity is the basis for understanding earthquake activity,evaluating earthquake risk and reducing earthquake hazards.At present,the determination of fault activity age can be divided into two categories according to different dating objects:One is the sediments related to fault activity to define the activity age,mainly through the dating of dislocated and non-displaced strata and landforms.For sediment dating,there are currently many dating techniques available with high reliability,such as 14C method,luminescence dating,etc.Therefore,those dating methods are currently the main ones for determining the chronology of fault movement.The other is the dating of materials and geomorphic surfaces directly related to fault activity.Such as fault gouges,bedrock slip surfaces(including associated or secondary substances on fault surfaces or slip surfaces),veins filled in fault zones,etc.However,the Quaternary activity of the faults in the carbonate rock area is difficult to determine due to the lack of Quaternary sediment cover.The latest research shows that recrystallized carbonate formed on the fault surface in carbonate rock area provides an ideal material for the study of such faults using ESR method.In the carbonate rock area,during the fault activity,the heat produced by friction leads to melting of the frictional surface of the rocks and produces a thin layer(~2mm)of recrystallized carbonates.The recrystallized carbonate with obvious fault scratches is the product of dynamic metamorphism of the frictional surface due to the local high temperature and pressure environment generated by the rapid friction of the two walls of fault during the fault activity,and its age coincides with the fault movement.The recrystallization experienced by recrystallized carbonate can clear the accumulated ESR signals before the fault occurs,and the new ESR signals accumulation begins after the fault movement.Therefore,the chronology of fault activity can be obtained by determining the age of recrystallized carbo

关 键 词：ESR测年 碳酸盐岩 基岩断层 里德尔剪切 那坡断裂 

分 类 号：P597[天文地球—地球化学]