共查询到19条相似文献，搜索用时 125 毫秒
1.
柯坪逆冲推覆构造带是西南天山山前晚新生代以来形成的活动逆断裂-褶皱带,由5~6排近平行的弧形褶皱带组成,出露地层为寒武系—第四系。背斜形态多为复式箱状背斜和不对称的斜歪背斜,分别与断层弯曲背斜和断层扩展背斜的几何形态一致。地震勘探资料显示,各褶皱带前缘活动逆断裂在深部归并于统一的、由寒武系中的石膏层组成的滑脱面。滑脱面深度具有南浅北深、东浅西深的特点,皮羌断裂西侧滑脱面深度约为9km,东侧滑脱面深度为5km。在柯坪逆冲推覆构造中部的皮羌断裂东西两侧各5km和8km的位置,以断层弯曲褶皱和断层扩展褶皱构造模型为指导,用线长平衡的方法完成了2条长度分别为78km和73km的平衡地质剖面,恢复到变形前的形态后计算出这2条剖面上的地壳缩短量分别为40km和45km,缩短率为33%和37%。由于对柯坪逆冲推覆构造开始形成时间的证据较少,所以要计算长期的缩短速率是比较困难的。对比天山南麓库车活动逆断裂-褶皱带的形成时代,以及柯坪逆冲推覆构造与印干断裂的关系,认为柯坪逆冲推覆构造形成于第四纪早期的西域砾岩沉积阶段,按距今2.5Ma计算,柯坪逆冲推覆构造的地壳缩短速率是15.4~17.3mm/a 相似文献
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沿格尔木—五道梁公路测线 1979,2 0 0 1年的 2期水准观测资料表明 :1)东昆仑山及可可西里地区现今相对于柴达木盆地仍在发生继承性的隆升运动。 1979— 2 0 0 1年期间 ,昆仑山口主峰一带相对于格尔木约上升了 2 80mm ,上升速率高达 15mm/a ;五道梁相对于格尔木上升了约 2 10mm ,上升速率约 10mm/a。 2 )昆仑山口至五道梁之间的可可西里地区 ,在相对于柴达木盆地以 7mm/a的速度整体抬升的同时 ,还相对于南、北两侧的五道梁和昆仑山隆起区以 3～ 7mm/a的速度下沉。 3)格尔木—五道梁剖面垂直形变整体符合俯冲 -逆掩地壳增厚模式 ,其中 ,沿西大滩断裂、中昆仑山断裂和昆仑山北缘断裂带的逆冲推覆运动 ,占了整个东昆仑山现今构造隆起的大部分 ,其逆冲推覆运动有自南向北衰减的特点。 4 )地质调查结果表明 ,沿 2 0 0 1年 11月 14日昆仑山口西MS8.1地震 35 0km的左旋破裂带 ,可以划分出若干个不均匀错动段 ,错动量最大可达 6m ,最小只有 2m。基于Okada (1985 )位错模型的理论计算结果表明 ,地震断层不均匀左旋错动可以在昆仑山口破裂带 相似文献
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塔里木盆地西南前陆构造分段及其成因 总被引：13，自引：0，他引：13
大量野外调查和地球物理资料构造解释发现, 塔里木盆地西南凹陷周边前陆盆地带具有沿前陆走向构造分段的规律性, 即在西昆仑-帕米尔和西南天山前陆发育了一系列相间分布的由山系向盆地逆冲的弧形推覆构造系统及由塔里木盆地西南凹陷向山系反冲的弧形反冲构造系统, 逆冲与反冲构造间以走滑或斜冲断层相隔; 塔西南凹陷基底的北东向隆起和凹陷与前陆构造分段具成因联系, 发现薄皮弧形推覆构造段对应基底构造上隆区(小于10 km), 塔里木盆地反冲构造段对应基底构造下凹区(大于8 km). 沿造山带走向隆升幅度和速率或变形格局的差异、前陆盆地多个沉降中心及巨厚沉积盖层、盆地基底构造中隆起带和凹陷带及前陆盆地沉积盖层中存在多层膏岩层等软弱层是塔西南盆地前陆构造分段产生的控制因素, 而晚第三纪以来西昆仑-帕米尔与西南天山再造山隆升与塔里木盆地基底构造深浅部不同耦合变形作用是塔里木盆地西南前陆构造分段的主因. 相似文献
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依据钻孔系统稳态测温、静井温度资料与实测热导率数据分析了柴达木盆地地温场分布特征,建立了柴达木盆地热导率柱,新增了17个大地热流数据.柴达木盆地现今地温梯度介于17.1~38.6℃·km-1,平均为28.6±4.6℃·km-1,大地热流介于32.9~70.4mW·m-2,平均55.1±7.9mW·m-2.盆地不同构造单元地温场存在差异,昆北逆冲带、一里坪坳陷属于"高温区",祁南逆冲带属于"中温区",三湖坳陷、德令哈坳陷及欧龙布鲁克隆起属于"低温区",盆地现今地温场分布特征受控于地壳深部结构、盆地构造等因素.以现今地温场为基础,采用磷灰石、锆石裂变径迹年龄分布特征定性分析与径迹长度分布数据定量模拟相结合,研究了柴达木盆地晚古生代以来的沉积埋藏、抬升剥蚀和热演化史,并结合区域构造背景,对柴达木盆地构造演化过程进行了探讨,研究表明柴达木盆地晚古生代以来经历了六期(254.0—199 Ma,177—148.6 Ma,87—62 Ma,41.1—33.6 Ma,9.6—7.1 Ma,2.9—1.8 Ma)构造运动,六期构造事件与研究区构造演化的动力学背景相吻合.其中白垩纪末期(87—62 Ma)的构造事件导致了柴达木盆地东部隆升并遭受剥蚀,欧龙布鲁克隆起形成雏形,柴达木盆地北缘在弱挤压环境下形成坳陷盆地;中新世末的两期构造事件(9.6—7.1 Ma和2.9—1.8 Ma)使柴达木盆地遭受强烈挤压,盆地快速隆升,构造变形强烈,基本形成现今的构造面貌. 相似文献
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本文对柴达木盆地东部新生代盆地结构和构造演化进行了研究.地震剖面揭示柴达木盆地东部新生界分别向南、北盆地边缘变薄和尖灭,盆地北部被欧龙布鲁克山和埃姆尼克山隆起强烈改造.通过对新生代地层厚度横向变化以及地层剖面分析,确定欧北断裂自中新世晚期开始向北逆冲,导致欧龙布鲁克山发生隆升和德令哈凹陷的形成.埃北断裂从上新世开始活动,与欧北断裂同时向北逆冲,导致德令哈凹陷进一步沉降,形成厚度达2600m的狮子沟组.埃南断裂在第四纪开始大规模向南逆冲,不仅造成其北侧的欧龙布鲁克山和埃姆尼克山隆起强烈抬升和向南推覆,而且导致南侧霍布逊凹陷的形成,成为柴达木盆地第四纪沉积中心.早期提出的前陆盆地和背驮式盆地模型显然不能解释柴达木盆地东部新生代构造格架和演化历史.本次研究认为柴达木盆地东部的形成是强烈的水平挤压作用导致地壳发生大规模褶皱的结果,即柴达木盆地东部新生代是一个大规模向斜.该向斜盆地模型很好地解释了新生代地层向盆地边缘减薄以及沉积中心主要位于盆地中部等现象.了解柴达木盆地东部构造发展对了解青藏高原侧向扩展具有重要意义. 相似文献
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已经利用近垂直反射地震叠偏剖面得到太平洋板块西向俯冲远程应力场形成上部地壳滑脱断裂的证据,在此基础上,利用油气地震叠偏剖面发现中远程的蒙古—鄂霍茨克缝合带、远程的太平洋板块西向俯冲带在松辽盆地滨北地区浅部基底共同作用形成的逆冲推覆断裂系统.该断裂系统基本呈双向形式,纵向与横向上表现出不均匀的强度,向西逆冲推覆的断裂系统厚度范围可达到约3~4 km,向东的断裂系统厚度范围可达到约1~2 km,断裂系统组构比较复杂.经过对控盆断裂孙吴—双辽断裂两侧地球物理场分布特征的分析,认为松辽盆地浅部基底的逆冲推覆断裂系统是叠加在孙吴—双辽断裂之上的新的断裂系统.考虑到蒙古—鄂霍茨克缝合带在远离1000多公里之外所产生的内蒙古阴山—燕山大型逆冲推覆断裂带以及松辽盆地的区域构造位置,认为在松辽盆地南部和滨北地区孙吴—双辽断裂构造线之外也应该存在浅部基底内的逆冲推覆断裂. 相似文献
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准噶尔盆地东缘构造:阿尔泰与北天山造山带交接转换的陆内过程 总被引：1，自引：0，他引：1
准噶尔盆地位于中亚造山带西段,地表地质已有大量成果,但对该盆地深部结构构造研究相对薄弱,这制约了对该区构造演化的认识.通过对研究区大量二维地震剖面的详细构造解释,揭示出准噶尔盆地东缘主要的逆冲断裂有:乌伦古东、红盆、红盆南、喀拉萨依、滴水泉北、滴水泉南和沙西等断裂.断裂整体组合表现为向北西发散、向南东收敛的逆冲-走滑构造特征,可分为三组构造体系.北部叠瓦式褶皱-逆冲体系位于研究区北部,走向北西,倾向北东,表现为自北向南的叠瓦式逆冲推覆构造,整体上具有北老南新的特征,断裂最早形成于石炭纪,之后向南不断拓展.中部逆冲-走滑体系位于研究区中部,近东西走向,断面陡立,印支期为左行压扭,燕山期发生右行走滑,伴生少量小型正断层.南部褶皱-逆冲体系位于研究区南部,北东走向,倾向北西,分支断裂主体均为走向北东的逆断层.全区断层相关褶皱常见有断展和断弯褶皱.区域构造对比表明,在南阿尔泰和北天山两大造山带的挤压汇聚作用下,准噶尔盆地东缘在三叠纪-早白垩世期间持续发生陆内变形.其中研究区北部主控断裂指示了自北向南的逆冲推覆,动力来自南阿尔泰造山带的持续挤压;南部褶皱不对称性和主逆冲断层指示动力来自北天山造山带的持续挤压;中部走滑断裂早期逆冲作用较强,后期叠加走滑构造,是南、北两大动力系统发生复杂交接转换的结果,并调节了盆地内部次级块体的运动,使其向西挤出. 相似文献
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研究区胶东东部位于华北东部苏鲁超高压变质带东端, 发育逆冲推覆构造. 采用多尺度构造研究和构造年代学研究相结合的方法, 可将胶东东部逆冲推覆体划分为石岛推覆体、荣成推覆体、米山推覆体、牟平推覆体等四个推覆体. 这些推覆体以相应的走滑逆冲型剪切带为底界, 主要活动于中生代. 研究表明, 由石岛剪切带、荣成剪切带至牟平剪切带, 古差异应力值和韧性变形强弱序列呈现逐渐降低的趋势, 与变形温度的变化趋势呈负相关. 根据逆冲推覆构造研究、40Ar/39Ar同位素测年数据以及前人在区域上的同位素构造年代学研究成果, 推测研究区中生代构造的发展主要经历了四期运动: 三叠纪末(约210~180 Ma)的逆冲推覆运动; 侏罗纪-早白垩世(约180~130 Ma)的伸展运动; 早白垩世(130~120 Ma)的走滑逆冲运动; 晚白垩世以后(约120 Ma~)的伸展运动. 其中, 早白垩世(130~120 Ma)的走滑逆冲运动期剪切带的活动序列为石岛剪切带→荣成剪切带→牟平剪切带→米山剪切带, 引起了推覆体的逆时针旋转效应. 胶东东部逆冲推覆构造与郯庐断裂带的两期走滑事件时代吻合、运动学相容, 可吸收或调节部分郯庐断裂带的走滑运动量, 从而导致该断裂带北段走滑量的显著变小. 相似文献
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柴达木盆地北缘(柴北缘)出露侏罗纪地层,其中以大煤沟地区发育最为完整.整个侏罗系发育具有辫状河河道、滨浅湖及辫状河三角洲沉积体系特征的地层序列,厚度达到1100m.利用地层序列、砂岩碎屑组分及LA-ICP-MS微区定年方法,对柴北缘侏罗系沉积物源体系进行了研究.砂岩Dickinson图解显示其主要来源于再旋回造山带、碰撞缝合带和褶皱-逆冲带物源区.砂岩碎屑锆石U-Pb年代学同位素分析结果表明,早侏罗世具有1764~2496Ma(峰值年龄1787、2077和2440Ma);中晚侏罗世具有相同的年龄谱特征,分别是197~291Ma(峰值年龄238Ma),214~278Ma(峰值年龄238Ma);358~484Ma(峰值年龄404Ma),370~456Ma(峰值年龄418Ma);645~920Ma(峰值年龄875Ma),578~1160Ma(峰值年龄940Ma);1390~1991Ma(峰值年龄1875Ma),1550~1829Ma(峰值年龄1708Ma);2048~2484Ma(峰值年龄2272Ma),2161~2738Ma(峰值年龄2335Ma).研究表明,柴北缘侏罗纪沉积物源区由全吉地块(早侏罗世)扩大至柴北缘构造带、全吉地块、祁连山(中晚侏罗世).沉积物源区的显著变化是早中侏罗世之交发生的强烈构造运动在柴达木盆地内部的沉积物质表现. 相似文献
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1902年阿图什81/4级地震发生在西南天山山前推覆构造体中,逆冲推覆构造由推覆体的根部断裂、推覆体、滑脱断层和前缘逆断裂-褶皱等组成,大地震的发震断裂往往是推覆构造的根部断裂,而地震地表破裂和同震褶皱隆起则位于山前逆断层-褶皱带内。高震级的潜在震源区(MU7.5)对应于低速的天山地块和高速的塔里木地块之间的根带断裂,其长度对应于推覆体根带断裂的长度,宽度对应于根带隐伏逆冲断裂在地表的投影宽度。推覆体前缘的每个活动逆断裂-背斜对应于一个潜在震源(MU≤7.5),其长度与活动逆断裂-背斜的长度相等,宽度应覆盖活动褶皱的两翼。潜在震源的矩震级上限由W-C统计关系式确定,其中发震断裂的面积为活动褶皱的长度与隐伏断坡宽度的乘积。 相似文献
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柴达木盆地东部周缘造山带内保存有较完整的晚古生代-早中生代沉积记录,但盆地内至今仍未发现二叠系-三叠系.为探讨柴东地区二叠纪-三叠纪有无沉积及隆升历史等关键地质问题,本文首先利用古温标法恢复晚海西-印支期剥蚀量,随后,通过物源分析法获得印支期柴东北缘隆升的沉积学证据.结果表明,印支运动前,柴东地区残留石炭系顶界面埋深普遍超过2500m,晚海西-印支期剥蚀量为2100~4300m,剥蚀量从南往北逐渐减小.柴东地区曾沉积了2000~3000m的二叠系-三叠系,随后被整体剥蚀.晚二叠世以来,随着古特提斯洋往北俯冲,盆地周缘开始隆升.早三叠世柴东北缘经历了一次快速隆升,先期的多套沉积地层与结晶基底被迅速剥蚀并为宗务隆南缘的隆务河群砾岩沉积提供物源.中三叠世海水往北和往东退出研究区.晚三叠世,松潘-甘孜地体强烈碰撞挤压使得东昆仑-柴达木地体下地壳显著缩短和增厚,柴东地区被整体抬升,并且形成了南高北低的古地貌格局,在古气候与水系作用下,二叠系-三叠系与部分石炭系被全部剥蚀并搬运至宗务隆、南祁连及松潘-甘孜一带. 相似文献
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LiGuang Mao AnCheng Xiao Lei Wu BenLiang Li LiQun Wang QianQian Lou YouPu Dong SuHua Qin 《中国科学:地球科学(英文版)》2014,57(11):2726-2739
The Eastern Kunlun Mountains play an important role in the growth and eastward extrusion of the Tibetan Plateau. Tectonic and sedimentary study of the Cenozoic Qaidam Basin, especially the southern part, provides key evidence for understanding their evolution. Here we present evidence including isopach maps, seismic sections and sedimentary analysis of single well to illustrate the sedimentary development of the basin and the structural features of its southern margin. The Qaidam Basin extended across Qiman Tagh-Eastern Kunlun Mountains in the early Cenozoic and withdrew northward at ca. 35.5 Ma, and then buckled as an EW striking elliptical depression since ca. 14.9 Ma, with the main depocenter migrating eastward. Our results support the view that the Kumukol and Hoh Xil basins joined the Qaidam Basin in the early Cenozoic time and we propose the Eastern Kunlun Mountains uplifted in the mid-Miocene. 相似文献
14.
Cenozoic basin-forming processes in northwestern Kyushu were studied on the basis of geological and geophysical data. Gravity anomaly analysis delineated four sedimentary basins in the study area: Goto-nada, Nishisonogi, Amakusa-nada, and Shimabara. Borehole stratigraphy and reflection seismic interpretation suggest that the Goto-nada Basin was subdivided into the Paleogene and Plio-Pleistocene depocenters (Goto-nada 1 and 2). In the Paleogene, Amakusa-nada Basin was rapidly subsiding together with the Shimabara Basin as part of a large graben. Goto-nada 1 and Nishisonogi basins belonged to another depositional area. After stagnant subsidence stage in the early Miocene, the study area became a site of basaltic activity (since 10 Ma) and vigorous subsidence in the Plio-Pleistocene. Goto-nada 2 Basin is accompanied with numerous east–west active faults, and separated from the Amakusa-nada Basin by a northeast– southwest basement high, Nomo Ridge. Plio-Pleistocene subsidence of the Amakusa-nada Basin is related with low-angle normal faulting on the eastern flank of the Nomo Ridge. Shimabara Basin is a composite volcano-tectonic depression which is studded by east–west faults. Focal mechanism on active faults suggests transtensional stress regime in the study area. 相似文献
15.
本文通过背斜褶皱变形与低温热年代学年龄(磷灰石和锆石(U-Th)/He、磷灰石裂变径迹)端元模型研究,约束低起伏度、低斜率地貌特征的四川盆地南部地区新生代隆升剥露过程.四川盆地南部沐川和桑木场背斜地区新生代渐新世-中新世发生了相似的快速隆升剥露过程(速率为~0.1 mm/a、现今地表剥蚀厚度1.0~2.0 km),反映出盆地克拉通基底对区域均一性快速抬升冷却过程的控制作用.川南沐川地区磷灰石(U-Th)/He年龄值为~10-28.6 Ma, 样品年龄与古深度具有明显的线性关系,揭示新生代~10-30 Ma以速率为0.12±0.02 mm/a的稳态隆升剥露过程.桑木场背斜地区磷灰石裂变径迹年龄为~36-52 Ma,古深度空间上样品AFT年龄变化不明显(~50 Ma)、且具有相似的径迹长度(~12.0 μm).磷灰石裂变径迹热演化史模拟表明桑木场地区经历三个阶段热演化过程:埋深增温阶段(~80 Ma以前)、缓慢抬升冷却阶段(80-20 Ma)和快速隆升剥露阶段(~20 Ma-现今),新生代隆升剥露速率大致分别为~0.025 mm/a和~0.1 mm/a.新生代青藏高原大规模地壳物质东向运动与四川盆地克拉通基底挤压,受板缘边界主断裂带差异性构造特征控制造就了青藏高原东缘不同的边界地貌特征. 相似文献
16.
天山是中亚造山带重要组成部分,其中-新生代构造热演化及隆升剥露史研究是认识中亚造山带构造变形过程与机制的关键.本文应用磷灰石(U-Th)/He技术重建中天山南缘科克苏河地区中-新生代构造热演化及隆升剥蚀过程.磷灰石(U-Th)/He数据综合解释及热演化史模拟表明该地区至少存在晚白垩世、早中新世、晚中新世3期快速隆升剥蚀事件,起始时间分别为~90Ma、~13Ma及~5Ma,且这3期隆升剥蚀事件在整个天山地区具有广泛的可对比性.相对于磷灰石裂变径迹,磷灰石(U-Th)/He年龄记录了中天山南缘地质演化史中更新和更近的热信息,即中天山在晚中新世(~5 Ma)快速隆升剥蚀,其剥蚀速率为~0.47mm·a~(-1),剥蚀厚度为~2300m.总体上,中天山科克苏地区隆升剥蚀起始时间从天山造山带向昭苏盆地(由南向北)逐渐变老,表明了中天山南缘隆升剥蚀存在不均一性,并发生了多期揭顶剥蚀事件. 相似文献
17.
DETRITAL ZIRCON U-PB DATING OF MODERN RIVERS' DEPOSITS IN PAMIR,SOUTH TIAN SHAN AND THEIR CONVERGENCE ZONE 
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下载免费PDF全文 By dating detrital zircon U-Pb ages of deposition sequence in foreland basins, we can analyze the provenance of these zircons and further infer the tectonic history of the mountain belts. This is a new direction of the zircon U-Pb chronology. The precondition of using this method is that we have to have all-around understanding to the U-Pb ages of the rocks of the orogenic belts, while the varied topography, high altitude of the zircon U-Pb ages of the orogenic belts are very rare and uneven. This restricts the application of this method. Modern river deposits contain abundant geologic information of their provenances, so we can probe the zircon U-Pb ages of the geological bodies in the provenances by dating the detrital zircon U-Pb ages of modern rivers' deposits. We collected modern river deposits of 14 main rivers draining from Pamir, South Tian Shan and their convergence zone and conducted detrital zircon U-Pb dating. Combining with the massive bed rock zircon U-Pb ages of the magmatic rocks and the detrital zircon U-Pb ages of the modern fluvial deposit of other authors, we obtained the distribution characteristics of zircon U-Pb ages of different tectonic blocks of Pamir and South Tian Shan. Overlaying on the regional geological map, we pointed out the specific provenance geological bodies of different U-Pb age populations and speculated the existence of some new geological bodies. The results show that different tectonic blocks have different age peaks. The main age peaks of South Tian Shan are 270~289Ma and 428~449Ma, that of North Pamir are 205~224Ma and 448~477Ma, Central Pamir 36~40Ma, and South Pamir 80~82Ma and 102~106Ma. The Pamir syntaxis locates at the west end of the India-Eurasia collision zone. The northern boundary of the Pamir is the Main Pamir Thrust(MPT)and the Pamir Front Thrust(PFT). In the Cenozoic, because of the squeezing action of the India Plate, the Pamir thrust a lot toward the north and the internal terranes of the Pamir strongly uplifted. For the far-field effect of the India-Eurasia collision, the Tian Shan on the north margin of the Tarim Basin also uplifted intensely during this period. Extensive exhumation went along with these upliftings. The material of the exhumation was transported to the foreland basin by rivers, which formed the very thick Cenozoic deposition sequence. These age peaks can be used as characteristic ages to recognize these tectonic blocks. These results lay a solid foundation for tracing the convergence process of Pamir and South Tian Shan in Cenozoic with the help of detrital zircon U-Pb ages of sediments in the foreland basin. 相似文献
18.
Thermal histories of Cretaceous sedimentary basins in the Korean peninsula have been assessed to understand the response of the East Asian continental margin to subduction of the Paleo‐Pacific (Izanagi) Plate. The Izanagi Plate subducted obliquely beneath the East Asian continent during the Early Cretaceous and orthogonally in the Late Cretaceous. First, the Jinan Basin, a pull‐apart basin, was studied by illite crystallinity and apatite fission‐track analyses. Analytical results indicate that Jinan Basin sediment was heated to a maximum temperature of approximately 287°C by burial. The sediment experienced two cooling episodes during ca 95–80 Ma and after ca 30 Ma, with a quiescent period between them. A similar cooling pattern is recognized in the Gyeongsang Basin, the largest Cretaceous basin in Korea. The Jinan and Gyeongsang Basins were cooled mainly by exhumation between ca 95 and 80 Ma, but the former was exhumed slightly earlier than the latter by transpressional force due to the subduction direction change of the Izanagi Plate. Comparison of thermal history of Korean Cretaceous basins with those of granitoids in northeastern China and the accretionary complexes in southwestern Japan reveals that the Upper Cretaceous regional exhumation of the East Asian continental margin including the Korean peninsula during ca 95–80 Ma was facilitated by the subduction of the Izanagi–Pacific ridge, which migrated northeastwards with time, resulting in the end of regional exhumation at ca 80 Ma in this region. 相似文献
19.
The magnitude (M
w) 7.9 Wenchuan earthquake occurred on 12 May 2008 in the Longmen Shan region of China, the transition zone between the Tibetan
Plateau and the Sichuan Basin, resulting in widespread damage throughout central and western China. The steep, high-relief
eastern margin of the Tibetan Plateau has undergone rapid Cenozoic uplift and denudation accompanied by folding and thrusting,
yet no large thrust earthquakes are known prior to the 2008 M
w 7.9 Wenchuan earthquake. Field and excavation investigations reveal that a great historical earthquake occurred in the Sichuan
region that ruptured a >200-km-long thrust fault within the Longmen Shan Thrust Belt, China, which also triggered the 2008
M
w 7.9 Wenchuan earthquake. The average co-seismic slip amount produced by this historical earthquake is estimated to be 2–3 m,
comparable with that caused by the 2008 Wenchuan earthquake. Paleoseismic and archaeological evidence and radiocarbon dating
results show that the penultimate great earthquake occurred in the Sichuan region during the late Tang-Song Dynasty, between
AD 800 and 1000, suggesting a recurrence interval of ~1,000–1,200 years for Wenchuan-magnitude (M = ~8) earthquakes in the late Holocene within the Longmen Shan Thrust Belt. This finding is in contrast with previous estimates
of 2,000–10,000 years for the recurrence interval of large earthquakes within the Longmen Shan Thrust Belt, as obtained from
long-term slip rates based on the Global Positioning System and geological data, thereby necessitating substantial modifications
to existing seismic-hazard models for the densely populated region at the eastern marginal zone of the Tibetan Plateau. 相似文献