四川盆地东南部早三叠世地震事件沉积及其地质意义  

Seismites and Their Geological Significance in Early Triassic of Southeast Sichuan Basin

作　　者：张廷山[1,2] 陈晓慧[2] 刘治成[1] 

机构地区：[1]"油气藏地质与开发工程国家重点实验室"(西南石油大学),成都610500 [2]西南石油大学资源与环境学院,成都610500

出　　处：《沉积学报》2012年第3期477-489,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金重点项目(批准号:40334038)及国家自然科学基金项目(批准号:40572077)的联合资助

摘　　要：四川盆地南部及东南部下三叠统飞仙关组和嘉陵江组中常发育有一系列宏观及微观的软沉积物变形、震积角砾岩块、板状砾屑、层内微断层等特殊的地震成因沉积构造。飞仙关组震积岩在重庆北碚白庙子剖面飞仙关组第一、二段中产出,嘉陵江组震积岩产于四川叙永龙洞湾嘉陵江组第二段及四川兴文、贵州习水等地的相同层位中,其沉积序列明显,反映了古地震从开始至平静的全过程。作者认为,早三叠世时,上扬子板块西缘以川西义敦弧的演化为代表的三江构造带活动强烈,可能与四川盆地早三叠世震积岩的形成有联系,随着三江构造带板块碰撞、洋壳俯冲消减,能在较大区域内引发地震活动、火山喷发。The seismites emerge in the first and sencond members of Lower Triassic Feixianguan Fm.in Baimiaozi section,Beibei,Chongqing,China and in the second member of Lower Triassic Jialingjiang Fm.in Longdongwan,Xuyong county,the southern Sichuan province,China,as well as in the same stratigraphic sequences in Xingwen county,Sichuan province and Xishui county,Guizhou province. There are some macroscopic and microscopic sedimentary structures of seismic events in the outcrops,drilling cores and thin sections including the following basic types could be observed： Soft-sediment liquefied deformation structures include curled deformation（sliding deformation structure,＂sausage structure＂） and microscopic folds（laminated plastic deformation）.In the first member of Feixianguan Fm.at Beibei,Chongqing.Microscopic folds（lamina plastic deformation） are found in the second member of Feixianguan Fm.at Longdongwan,and microscopic folds emerge in laminated thin-layer limestone,presenting slight folds in laminated thin-layer limestone and their low radian with undulation.In addition to study areas,some soft-sediment deformation structures such as convolute beddings,microscopic folds and so on are developed in the first member of Feixianguan Fm.at Jichang,Xuanhan county,Sichuan province,China,and may be related to paleoearthquake activities. The tabular-pebbles with different-size diameters are developed in the lower part of the second member of Feixianguan Fm.,interbedded with laminated thin-layer micritic limestone of normal sequences.The sedimentary characteristics of tabular gravel layers are also comparable with those in the second member of Feixianguan Fm.at Beibei,Chongqing. The gravels are developed with different size,shape and psephicitie in the first member of Feixianguan Fm.in Baimiaozi,Beibei Chongqing,and the second member of Jialingjiang Fm.in Longdongwan,Xuyong,Sichuan province,the shape being irregular mass,nearly spherical or tabular,the size ranging from 0.5 to 25cm,the lithology being grey or grey w

关 键 词：震积岩 沉积序列 成因及地质意义 早三叠世 四川盆地 

分 类 号：P512.2[天文地球—地质学]