燕山构造带西段千家店盆地生长构造与生长地层

Izanagi板块在晚中生代向NW前进式俯冲于欧亚板块东部之下,诱发形成了燕山构造带一系列挤压构造,然而构造的具体形成时间以及弥散分布于燕山构造带的山间盆地的控盆构造属性、构造活动与沉积作用之间的相互关系依然存在着较大的争议.本文基于对北京北部千家店盆地上侏罗统-下白垩统土城子组的沉积作用、物源及盆缘、盆内构造的精细研究,认为:千家店盆地西缘发育断展褶皱型生长构造与生长地层,土城子组第二段顶部和第三段地层在盆地西缘生长,它们受控于翼部旋转模式的断展褶皱作用;千家店盆地内发育的两条小型逆冲断层,均表现为盆地基底下马岭组逆冲于土城子组地层之上,可能控制了断弯褶皱型生长地层的发育;盆地"源-汇"过程分析表明,尚义-平泉断裂上盘基底地层为千家店盆地晚侏罗世-早白垩世早期地层的主要物源区;断展褶皱型生长地层底界面处火山岩获得的最年轻的一组锆石206Pb/238U加权平均年龄为(140.8±2.4)Ma,它可能代表了断展褶皱型生长构造活动的起始时间.千家店盆地断展褶皱型生长构造和生长地层的发现,证明了千家店盆地早白垩世早期是受控于褶皱-逆冲作用的山间挠曲盆地.近E-W向的尚义-平泉断裂与NE向的千家店逆冲断层和盆内的两条逆冲断层可能构成一个统一的右行走滑式逆冲构造系统,共同控制了千家店盆地土城子组的沉积,其构造作用可能与侏罗纪至早白垩世初Izanagi板块向NW的前进式平板俯冲有关.     

冀北张家口地区同构造沉积过程及其与褶皱-逆冲作用耦合

"燕山运动"年代和燕山构造带侏罗纪的构造性质仍存在着争论.燕山山间盆地沉积地层记录了燕山运动的活动历史及盆地构造性质,开展盆-山系统同构造沉积及其构造控制关系研究,准确确定地层年代,重新建立年代地层格架是进一步揭示燕山侏罗纪至早白垩世构造变形机制、变形年代的有效途径.本文通过对燕山西段与太行山北段交接部位的冀北张家口地区褶皱-逆冲带与山间沉积盆地的构造和沉积结合研究表明,研究区沉积盆地中发育的所谓"侏罗纪地层"可能为晚三叠世-早侏罗世、中侏罗世和晚侏罗世-早白垩世早期地层;受生长褶皱-逆冲构造控制,在褶皱-逆冲带边缘形成褶皱前渊型、逆冲前渊型、断展褶皱型、断弯褶皱型及断弯褶皱与断展褶皱复合型生长地层;重建的由褶皱-逆冲带与挠曲盆地构成的晚三叠世-早侏罗世、中侏罗世、晚侏罗世和早白垩世早期的"源-汇"系统反映了燕山运动在研究区起始于中侏罗世;在晚侏罗世晚期-早白垩世早期至少发生了3次褶皱-逆冲事件,形成了基底卷入式褶皱-逆冲构造和小型山间挠曲盆地;基底卷入式褶皱-逆冲带与挠曲盆地"对"的自东向西迁移,可能受控于西太平洋"平板式"前进俯冲作用.     

塔里木盆地西南前陆构造分段及其成因

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.     

库车坳陷第三系构造层序的构成特征及其对前陆构造作用的响应

第三纪库车坳陷是在南天山强烈逆冲导致的挠曲沉降背景下发育的前陆盆地.区内的第三系可划分为四个区域性的沉积旋回或构造层序,它们均由微角度不整合或区域性冲刷面所分隔. 构造层序由下部水进和上部水退序列组成.每一构造层序的沉积构成反映了从前陆逆冲挠曲沉降到回弹上隆的演化过程. 构造层序界面的形成与回弹隆起、遭受剥蚀和随后的逆冲变形作用有关.第三纪前陆盆地的层序地层格架和沉积体系域的配置受到前陆构造作用的控制.从第Ⅰ至第Ⅳ构造层序的发育演化反映了第三纪南天山向库车前陆盆地不断逆冲的过程.坳陷北缘东、西部在沉积样式上存在明显差异: 库车县一线以西强烈的逆冲造山导致巨厚的山前扇砾岩带发育和角度不整合, 该线以东由于逆冲造山较弱而缺乏粗粒的扇带发育. 盆地基底的东、西分块可能是造成这种差异的深部原因.     

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

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.     

浙西北前陆褶皱冲断带初步研究

浙西北地区上二叠统长兴组(P_2c)和大隆组(P_2d)以及下三叠统政棠组(T_1z)是一套深水相浊积岩建造;区域构造环境初步分析表明浙西北地区具被动大陆边缘沉积楔特征.下三叠统政棠组(T_1z)与二叠系协调变形,构造变形样式总体上以向北西逆冲的冲褶席(duplex)~1)和逆冲叠瓦扇为特征,由东南往西北构造变形样式依次出现复式冲褶席(multi-duplex)、背形堆垛(Antiformal stack)和叠瓦扇组合,其中褶皱样式依次出现大型紧闭平卧-斜卧褶皱、中尺度尖棱褶皱和具圆筒状转折端的开阔褶皱.断层变化则由断层面产状几乎水平的多重复杂冲褶席系到缓倾的顶板冲断层-底板冲断层组合样式到叠瓦扇冲断层,显示出构造变形强度自南东向北西递减的特点.上三叠统乌灶组(T_3w)为前陆磨拉石盆地建造,变形样式以宽缓褶皱和逆断层组合为主.构造样式的空间展布规律变形强度向北西衰减的构造极性沉积-大地构造分析,均表明在(T_1-T_3)期间及随后的后构造变形作用中,浙西北持续地经历了自南东向北西的强烈挤压变形.     

西南天山-塔里木盆地结合带浅深构造关系 ——深地震反射剖面的初步揭露

盆山结合部的浅-深结构样式是进行陆内造山动力学研究与讨论的重要依据.2007年,在喀什东的天山与塔里木盆地之间的过渡带上,完成了一条近南北向的长度为121 km的主动源深地震反射剖面,显示出盆山结合部现今地壳尺度的构造格架.剖面南部呈现出10~12 km巨厚的沉积盖层,沉积盖层内发育滑脱断层;盆山结合部多排隆起构造以及天山山前上地壳显现出向北倾斜的断裂与地表地质观察吻合;盆山结合带展现出滑脱与逆冲推覆构造相关的断层褶皱;与塔里木盆地稳定沉积层相比,在南天山浅、中层地层受到强烈的变形改造,导致地层比较破碎,反射变弱、连续性较差;时间剖面上可以追踪到比较连续的Moho反射,从南向北有加深的趋势.深地震反射剖面揭露出的西南天山与塔里木盆地的这些浅-深构造,展现出塔里木盆地盖层向南天山滑脱与南天山向塔里木盆地逆冲推覆的特征,反映出陆内汇聚下的盆山耦合关系.     

文莱-沙巴盆地深水褶皱冲断带构造变形特征及成因机制

为揭示活动陆缘深水褶皱冲断带的特征及成因,本文利用地震和区域地质资料的综合分析,系统阐述了文莱—沙巴盆地深水褶皱冲断带的构造变形特征,并结合盆地演化动力学特点,探讨其构造变形机制及其对深水区油气成藏的影响.研究结果表明,文莱—沙巴盆地深水褶皱冲断带具有"垂向分期、平面分段"的特点,垂向上,以中中新统底界面为界可划分为下部（始新世-早中新世）和上部（中中新世-现今）两套逆冲褶皱冲断体系,其中下部逆冲褶皱冲断带的形成与古南海的俯冲作用密切相关,上部逆冲褶皱冲断带是中中新世以来三角洲前缘重力滑动与苏禄海扩张造成的区域挤压应力远程效应共同作用的结果,且苏禄海扩张造成的远程挤压效应主控平面上南北段褶皱冲断带变形的差异性,导致北段褶皱变形强度大于南段,具有背斜褶皱数量多、褶皱间距离短、逆冲断层倾角陡的特点,南段反之;且晚上新世以来北段深水区地层缩短量大于陆架区伸展量,两者之差为2~6 km,而南段两者相当,仅受三角洲前缘重力滑动影响.整个褶皱冲断带发育断弯、断展、断滑褶皱等3种断层相关褶皱以及叠瓦扇和冲起构造2种逆冲构造组合,是多期NW向挤压应力作用下形成的大型逆冲推覆构造,以前展式向盆地扩展.此外,由于中中新世以来逆冲断层的持续活动,研究区深水褶皱冲断带发育众多构造圈闭,油气成藏条件优越,且南段优于北段,靠近陆坡的近端优于远端,可作为勘探部署重点.     

中西部冲断带多尺度地球物理解释及其物理模拟实验

中西部冲断带形成于两古板块"镶嵌式"拼接成陆后的再冲断.多尺度地球物理资料解释表明,浅层构造变形具有"横向有序分带、垂向多属性分层、纵向差异分段"特征,深部构造变形表现为分层解耦和差异收缩,造山带与盆地的岩石圈在咬合冲断时强-弱层对置.本文利用物理模拟实验和延时摄影方法,基于"挤压-碰撞"模型正演了冲断带变形过程,实验结果表明:造山带仰冲盆地并相互拼接,前者冲起折返,后者前陆冲断;盆内滑脱层的存在会产生构造分层,上构造层的变形以断层相关褶皱为主,且扩展范围受控于滑脱层;上构造层的挤压缩短量比下构造层大,变形扩展更远;下构造层的变形以叠瓦构造和双重构造为主,其断层倾角由前陆向腹陆逐渐增大,断面由下凹变为上凸,断片由侧向叠置变为垂向叠置;高角度逆断层的变形经历了脆性变形、韧-脆性变形和韧性变形三个阶段.     

西南天山明尧勒背斜的第四纪滑脱褶皱作用

通过对明尧勒活动背斜喀浪勾律克河剖面生长前地层和翼部生长地层几何结构的填图以及变形河流阶地的系统测量,结合磁性地层及释光年代学研究,认为该背斜的滑脱褶皱作用起始于距今约1·6Ma,其总体几何结构形成于褶皱作用的早期,但其生长扩展并不完全遵从自相似性特征。持续的缩短作用部分被褶皱翼部陡倾膝折带的加长所吸收(由此导致背斜波幅的增加),另一部分可能是通过不同时期褶皱翼部不同膝折带组的旋转和迁移来实现的。明尧勒背斜的持续构造抬升是背斜区河流下切形成多级基座阶地的主因。晚第四纪褶皱的生长以背斜的垂直抬升为主,主要集中在北翼近核部,背斜宽度变化不大。背斜不同时期的抬升量和抬升速率均大于其缩短量和缩短速率,表明明尧勒背斜的变形以翼旋转为主(Pobletet al.,1996)。背斜自形成以来缩短速率和抬升速率均有减小的趋势     

利用河流阶地限定活动褶皱的类型和生长机制:运动学模型

与生长地层类似,在活动褶皱生长发育过程中形成的河流阶地堆积、阶地面与褶皱陡坎记录了褶皱发育的详细过程,其基本几何结构主要受控于下伏褶皱生长的机制与类型。文中讨论了简单膝折带迁移(恒定翼间角)生长断弯褶皱与断展褶皱、翼旋转(恒定翼长)滑脱褶皱、膝折带迁移滑脱褶皱、膝折带迁移-翼旋转联合作用以及弧形弯曲枢纽膝折带迁移褶皱作用下河流阶地的几何结构以及阶地面与下伏基座岩层间的角度关系,提出了这几类褶皱生长与河流阶地相互关系的运动学模型,同时考虑了河流加积和下切侵蚀作用对河流阶地最终几何结构的影响。在这些模型中,变形河流阶地和褶皱陡坎的基本几何结构既具有相似之处,也有截然不同之处。因此,通过对河流阶地和褶皱陡坎的细致填图、测量和测年,不仅可推断其下伏活动褶皱的生长变形机制,而且可以估算褶皱的隆升速率和控制褶皱生长的断层的滑动速率     

Migration of growth axial surfaces and its implications for multiphase tectono-sedimentary evolution of the Zhangwu fault depression,southern Songliao Basin,NE China

The normal fault-bend folding theory uses active axial surfaces, inactive axial surfaces, and growth axial surfaces to describe the geometric relationship between faults and deformation of a hanging wall. The dip of a growth axial surface is related to the fault slip rate and the basin sedimentation rate: higher fault slip rates result in smaller dips of growth axial surfaces, whereas higher basin sedimentation rates produce larger dips of growth axial surfaces. Moreover, the growth axial surface will be a straight line if both the fault slip and sedimentation rates remain relatively unchanged, but will become curved if both rates are variable. Therefore, the characteristics of growth axial surfaces can provide clear information on the evolution of faulting and deposition. By studying the seismic profiles of the Zhangwu fault depression of the southern Songliao Basin, we show that the migration of growth axial surfaces and unconformities can be used as indicators of basin development. Multiphase tectonic activity will not only produce unconformities but also result in migration of growth axial surfaces or inactive axial surfaces. Therefore, the normal fault-bend folding theory, particularly with regard to the evolution of growth axial surfaces, can be applied to the interpretation of geometric and kinematic evolutions of half-grabens and the exploration of related tectono-sedimentary processes.     

DEVELOPMENT OF TRANSVERSE DRANAGES AND FORMATION OF WIND GAPS ON ACTIVELY GROWING FOLD: REVIEW AND CASE STUDY

The most compelling phenomena for transverse drainage in active fold belt are lateral diversion of channels and development of water/wind gaps. This phenomenon is the result of competition between uplift and erosion, which is controlled by fault vertical/lateral propagation and segment linkage, fault geometry, climate condition and lithology. Previous studies found that the higher the uplift rate is, the greater number of wind gaps form, and the variation of the uplift rate is also critical to the sustainability of transverse rivers. Lateral propagation and linkage of several separate folds in fold-and-thrust belts will lead to defeat of streams and diversion into a trunk drainage; if the trunk is still unable to keep pace with uplift, water gap will be abandoned and left as a wind gap. For lateral propagation of an anticline associated with development of tear faults, the locations of wind/water gaps are likely to coincide with the trace of tear fault and it's not quite clear about the relation between tear faulting and stream deflection. Nonzero dip of the underlying detachment induces a lateral surface slope in the direction of fault propagation, which in turn makes rivers deflection more efficient. Climate and rock erodibility control the water/sediment discharge, and further influence river transport/incision capacity. The changing climate and rock erodibility conditions enable river to abandon the current waterway to create a wind gap unless they could down-cut through a growing fold. However, the role of climate cycle in the formation of wind gap is still controversial. In addition, wind gaps are commonly developed along the divides where parts of longitudinal river have been captured by transverse catchments. Generally, the development of transverse drainages and the formation of wind gaps in nature are result from a combination of tectonic and fluvial process. The wind gap pattern and transverse drainage evolution in fold-and-thrust belts contain plenty of information on fault growth, interaction between tectonic uplift and fluvial erosion, and development of sedimentary basin. Such researches have significant implications in geomorphology, seismic hazard assessment and hydrocarbon exploration. However, there are still many knowledge gaps on the study of transverse river evolution in active fold areas. First, adequate chronology and geomorphic/strata mark to quantify fold growth and erosion is commonly not available, which leads to a poorly constrained rate in both river incision and lateral propagation of growing folds. In addition, more geological and geomorphological processes could influence the evolution of transverse drainages. For examples, (1)during the formation of a young range or anticline, the mechanism of fault-related folding may change over time, e.g. from fault-propagation folding to surface breaking; (2)Besides the knickpoint retreat in downstream, efficient lateral planation and downstream sweep erosion are also important in understanding the erosion of folds by rivers flowing through it. These processes make the development of transverse drainage across folds more complex and should be considered in more comprehensive models. There are lots of rivers originating from the Tibetan plateau and cutting through young surrounding mountains. These surrounding mountains, such as Qilian Mountains, Tianshan Mountains and Longmen Mountains, are ideal areas for the study of transverse river evolution and wind gap formation. In the end, combining with the geological and geomorphological features of the Heli Shan-Jintanan Shan, north of Hexi Corridor, we propose that the Heihe River has experienced deflection, beveling and incision since Mid Pleistocene. These processes have led to 1)the formation of a wind gap on the western Heli Shan, 2)a layer of fluvial gravels from the Qilian Shan preserved on the top surface of the Jintanan Shan, and overlying angular unconformity upon older strata, and 3)the incision of the Heihe River to form the Zhengyi Gorge through the linked structure between Heli Shan and Jintanan Shan. Thus, we propose a general model for the development of transverse drainages in the central Hexi Corridor: deflection-beveling-incision.     

天景山断裂带前锋区第四纪构造变形及成因分析

通过野外详细填图,发现天景山断裂带走滑运动的前端,存在庙山和红尖山两排笼四纪逆冲断裂、褶皱构造带。     

熊坡背斜构造变形与蒲江-新津断裂活动特征

熊坡背斜位于龙门山构造带东南端的成都盆地内,是龙门山逆冲推覆构造向前推挤进入盆地内部的一个主要变形区域,与其配套发育的断裂为蒲江-新津断裂,断裂与背斜褶皱之间在构造变形模式上表现出明显的一致性。在褶皱和断裂的构造变形和活动特征上,熊坡背斜南段表现为一种不对称的褶皱,向NE方向发展表现为较为宽缓的对称褶皱形态,卷入的地层主要是中生代及其以前的地层,对蒲江-新津断裂的地貌调查结果表明,断裂没有对该区域内广泛发育的冲沟Ⅰ级阶地产生影响,而对山前发育的相当于南河(岷江Ⅰ级支流)Ⅳ级阶地的洪积台地有明显的控制作用,说明断裂活动时间应该为第四纪早期,到第四纪晚期活动减弱或是趋于静止     

THREE-DIMENSIONAL STRUCTURAL FEATURES OF THE PENGXIAN ACTIVE BLIND FAULT IN THE CENTRAL LONGMEN SHAN FRONT BELT

The Pengxian blind fault is a typical active fault in the central Longmen Shan front belt. It has important reference value for understanding the growth mode and process of the eastern Tibetan plateau. Because the fault is covered by the thick Upper Cenozoic strata in the western Sichuan Basin, its three-dimensional spatial distribution, structural style and formation mechanism remain unclear. In this paper, based on several high-resolution 3-D seismic reflection profiles, together with near-surface geological data and borehole data, we investigate the structural geometry of the Pengxian blind fault and build a 3-D model based on the results. We analyze the shape and scale of underground spatial distribution of the fault through a three-dimensional fault model. According to the theory of fault-related fold and fold-accommodation fault, this paper discusses the forming mechanism of the Pengxian buried structures. The shallow tectonic deformation in front of Longmen Shan is closely related to the detachment layer of the Middle and Lower Triassic, and this detachment layer f1 horizontally propagates into the Longquanshan anticline in the western Sichuan Basin. The Pengxian buried fault is a typical fault-bend fold and the f1 horizontally propagates into the western Sichuan Basin with a fault slip of 3.5km. The Pengxian blind fault is a high angle(50°~60°)thrust fault developed in the front wing of the kink-band zone, striking NE-SW, with a total length of~50km; But the fault is not connected with the Dayi buried fault in the south section of Longmen Shan. They are two different faults, and this defines the scale of the Pengxian blind fault. This limitation makes sense for analyzing and evaluating the magnitudes of potential earthquake. All above study provides research basis for further analysis of the potential seismic risk in this area. The Pengxian blind fault is parallel to the anticlinal axis with small amount of offset as a fold-accommodation fault. We believe that the fault formation is related to the fold deformation of the fold front limb. The study reveals the geometry, kinematics and formation mechanism of the Pengxian active fault, and provides a basis for further analysis of fault activity and hazard. Therefore, there is little possibility of strong earthquakes at the Pengxian blind fault due to its formation mechanism of the fault which is generally characterized by fold deformation and shortening deformation. In this paper, we discuss the location of Pengxian blind fault in the middle of Longmen Shan and Sichuan Basin. Because the Pengxian buried structures are in the transition area, the shortening amount in Pengxian indicates that the absorption in the basin is quite limited. It reflects the blocking effect of Sichuan Basin. In the study, we find that the relationship between folds, faults and sediments is an important part of tectonic interpretation; the theory of fault-related fold and fold-accommodation fault is well used for analysis. This would have great significance for the study of structural deformation, which can help to build a three-dimensional model of fault.     

Structural geometrical analysis and simulation of decollement growth folds in piedmont Fauqi Anticline of Zagros Mountains,Iraq

This study carried out detailed structural analyses of the plane structural deformation pattern and sectional structural deformation styles of the Fauqi Anticline by the 3D seismic section with full cover collection, and carried out the kinematical simulation of the Fauqi anticlinal deep decollement coupling shallow growth folds and faults based on the fault decollement fold model and the forward balanced geological section technique. The study subsequently evaluated the differentiated petroleum enrichment mechanism of the Fauqi Anticline by utilizing the results of the structural analysis and combining the spatial-temporal relationship analysis of the source, the reservoir, and the caprock. The results showed that the differentiated plane structural deformation pattern and hierarchical sectional structural deformation style were developed by the superposed coupling of deep decollement, syntectonic sedimentation of shallow growth strata, and the compression of the south-west horizontal tectonic stress from the Zagros Mountains. It was found that the differentiated structural deformation caused the differentiated enrichment of petroleum in the Fauqi Anticline. It was also found that the horizontal slip distance of the Fauqi Anticlinal Folds reached around 3.5 km by the simulation of deep decollement coupling the movement of the shallow growth folds and the faults.     

利用河流阶地限定活动逆断层相关褶皱晚第四纪变形机制和速率：方法与认识

发育在褶皱区的河流阶地作为一种发育广泛、易于定年的被动变形的地貌标志物,已越来越多地被应用到活动逆断层相关褶皱晚第四纪变形的研究中;结合前生长地层和生长地层,可限定褶皱缩短总量和变形起始时间等参数,恢复从开始生长至晚第四纪以来完整的生长演化历史。文中对正弦曲线状和尖棱状弯滑褶皱模型、经典断弯褶皱模型和纯剪切断顶褶皱模型进行了总结和讨论。这些模型的提出为限定褶皱变形提供了很好的方法,但不能完全概括自然界中的褶皱模型,这就需要更多的野外地质、数值模拟和实验模拟工作。     

帕米尔北缘弧形推覆构造带东段的基本特征与现代地震活动

帕米尔北缘弧形推覆构造带东段由强烈活动的艾卡尔特弧形活动褶皱－逆断裂带与卡兹克阿尔特弧形活动褶皱－逆断裂带南、北两条巨型边缘弧形构造带及其间的推覆构造构成。每个弧形带分别由多个不同级别的、相对独立的次级弧形构造组成。每个弧形构造实际上就是一个独立的逆冲推覆席体，都有其各自独特的几何学、运动学、动力学特征，但同时又具有自相似性特征。独立地震破裂区或形变带与独立活动的弧形推覆构造可能具有一定的对应关系     

ACTIVE FAULTS AND THEIR FORMATION MECHANISM IN THE EAST SEGMENT OF QIULITAGE ANTICLINE BELT,KUQA DEPRESSION

Based on geological and geomorphologic characteristics of the surface faults acquired by field investigations and subsurface structure from petroleum seismic profiles, this paper analyzes the distribution, activity and formation mechanism of the surface faults in the east segment of Qiulitage anticline belt which lies east of the Yanshuigou River and consists of two sub-anticlines:Kuchetawu anticline and east Qiulitage anticline. The fault lying in the core of Kuchetawu anticline is an extension branch of the detachment fault developed in Paleogene salt layer, and evidence shows it is a late Pleistocene fault. The faults developed in the fold hinge in front of the Kuchetawu anticline in a parallel group and having a discontinuous distribution are fold-accommodation faults controlled by local compressive stress. However, trenching confirms that these fold-accommodation faults have been active since the late Holocene and have recorded part of paleoearthquakes in the active folding zone. The fault developed in the south limb near the core of eastern Qiulitage anticline is a low-angle thrust fault, likely a branch of the upper ramp which controls the development of the eastern Qiulitage anticline. The faults lying in the south limb of eastern Qiulitage anticline are shear-thrust faults, which are developed in the steeply dipping frontal limb of the fault-propagation folds, and also characterized by group occurrence and discontinuous distribution. Several fault outcrops are discovered near Gekuluke, in which the Holocene diluvial fans are dislocated by these faults, and trench shows they have recorded several paleoearthquakes. The surface anticlines of rapid growth and associated accommodation faults are the manifestations of the deep faults that experienced complex folding deformation and propagated upward to the near surface, serving as an indicator of faulting at depth. The fold-accommodation faults are merely local deformation during the folding process, which are indirectly related with the deep faults that control the growth of folds. The displacement and slip rate of these surface faults cannot match the kinematics parameters of the deeper fault, which controls the development of the active folding. However, these active fold-accommodation faults can partly record paleoearthquakes taking place in the active folding zone.