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1.
古元古代拉伸构造模式——以胶北,辽东和吉南地区为例   总被引:6,自引:0,他引:6  
对胶北、辽东和吉南地区元古代层状岩系和第一幕构造变形作用的详细研究和综合分析,并以此为典型实例,提出了古元古代拉伸构造模式,即隆起-顺层分层滑脱构造模式。该上部隆起和上部盖层及两者之间的拆离型韧性剪切带三部分组成。核部隆起常由岩浆隆起或基底隆起构成,上部盖层内发育有顺层分层滑脱构造体系,由底部主滑脱面和内部次级滑脱面,低级骨脱面及其间的流褶层和片理化带构成,靠近核部隆起的盖层表现为正向滑脱,而滑脱  相似文献   

2.
对胶北.辽东和吉南地区古元古代层状岩系第一系构造变形作的详细研究和综合分析,并以此为典型实例,提出了古元古代拉伸构造模式,即隆起一顺层分层滑脱构造模式。该模式由核部隆起和上部盖居及两者之间的拆离型韧性剪切带三部分组成。核部隆起常由岩浆隆起或基底隆起构成,上部盖层内发育有顺层分层滑脱构造体系,由底部主滑脱面和内部次级滑脱面、低级滑脱面及其间的流褶居和片理化带构成,靠近核部隆起的盖居表现为正向滑脱,而滑脱前缘则表现为反向滑脱,具有滑覆特征。该模式一般发生在大规模收缩造山作用之前,由于区域拉伸作用,导致壳下地任上隆,形成岩桨隆起或基底隆起,使上覆盖层岩系重力失稳,发生滑脱,内部横向构造置换强烈,形成透入性片理,且平行区域地层层理  相似文献   

3.
塔里木盆地多层次滑脱构造与含油气远景探讨   总被引:21,自引:4,他引:21  
汤良杰 《地质学报》1992,66(2):97-107
塔里木盆地存在4个滑脱系统、多套滑脱层、多个主滑面和次滑面。浅层次滑脱构造以中、新生代地层发生褶皱-冲断为特征;中层次滑脱表现为古生代地层的逆冲推覆、滑脱褶皱和牵引背斜;深层次滑脱为发育在基底岩系中的韧性剪切带。塔北、塔中和塔南隆起,发育有中、深层次滑脱构造,它们是寻找大型油气田的主要油气聚集带。库车、西南和东南坳陷发育浅层次滑脱构造,是寻找中、小型油气田的有利构造带。  相似文献   

4.
华北地台东缘早元古代隆—滑构造模式   总被引:13,自引:1,他引:13  
刘永江  李三忠 《地质论评》1997,43(6):569-576
研究华北地台东部边缘早元古代拉伸构造及与变质核杂岩的比较,提出了隆-滑构造模式。它一般发生大规模收缩造山作用之前,由于区域拉伸作用,导致下地幔上隆,形成了岩浆隆起或基底隆起,使上覆盖层发生重力滑脱。该模式由核部隆起,上部盖层和其间的拆离韧性发带组成。  相似文献   

5.
塔北隆起古生代构造样式和构造反演   总被引:4,自引:0,他引:4       下载免费PDF全文
塔北隆起是塔里木盆地的主要含油气区,笔者利用地震剖面解释和平衡剖面技术对塔北隆起构造变形和构造演化进行了研究.塔北隆起构造变形存在明显的构造差异,西部英买力地区主要发育盖层滑脱式逆冲断层褶皱和"y"型压扭断层,而其东部主要发育基底卷入式逆断层及断层传播褶皱和反冲断层构造.造成塔北隆起东、西构造样式差异的机理主要有两点:一是东部地区对震旦纪一早奥陶世正断层在后期挤压作用下反转,二是英买力地区中寒武统盐层的发育.塔北隆起地区古生代构造演化也存在着一定的差异,塔北隆起东部震旦纪一早奥陶世发育大型正断层构造,而英买力地区为稳定碳酸盐岩台地;晚奥陶世至泥盆纪,塔北隆起东部牙哈断层发生反转,轮台凸起隆升,而英买力地区位于隆起的斜坡部位;石炭纪至二叠纪,塔北隆起东部大规模抬升,剥蚀严重,出露变质基底,英买力地区接受强烈的变形作用,主要发育盖层滑脱式逆断层和褶皱构造.  相似文献   

6.
研究发现,庐山东南麓中深变质岩系的顶部发育以糜棱岩、构造片岩为主体的顺层韧性剪切变形变质带,其上为滑脱断层和固态流动构造群落带及独具特征我多层滑脱构造形迹群。它们反映了前印支造山期伸展构造作用体制下形成的局部隆起-分层滑脱构造系特征。  相似文献   

7.
米仓山推覆构造的结构样式及演化特征   总被引:20,自引:0,他引:20  
采用变形剖面和平衡剖面综合分析方法研究米仓山地区中新生代构造格局,得出该区构造样式为一大型东西向和北东向叠加的推覆滑脱构造,变形剖面总体格局为推覆—断展复式背斜,次级变形单元具叠瓦扇、逆冲岩席、断展褶皱、层滑褶皱等多种样式。推覆构造演化经历了断展隆起、逆冲推覆、逆掩滑脱和复合叠加变形阶段。  相似文献   

8.
福建省含煤区广泛发育各种型式的滑脱构造,可分为伸展机制的滑覆构造与收缩机制的推覆构造两类。煤系基底与盖层以及盖层内部的强度差异是滑脱构造发育的基础;基底隆起与盖层坳陷的构造格局为其发育的另一条件。滑脱构造表现出多层次、多成因、多期次.具有侏罗山式脱顶.拆离,不协调变形多种特点.滑脱构造对找煤有着密切的关系。  相似文献   

9.
论黄陵背斜水平滑移兼论三峡水库绕黄陵背斜渗漏   总被引:1,自引:0,他引:1  
本文以黄陵背斜盖层形态判定了黄陵背斜的隆起、水平滑移直至构造应力方位,探讨了黄陵背斜盖层的层间滑脱构造,进而提出了未来三峡水库的水有绕黄陵背斜盖层沿这些滑脱构造发生渗漏的论断。作者依现有构造形态,粗算了黄陵背斜向S236°W方向水平滑移16.5km,垂直隆起4.85km,同时也估量了未来三峡水库可能渗漏途径长约42.8km。  相似文献   

10.
推覆、滑脱构造为福建省主要控煤构造,但在其南、北两段含煤区的表现迥然不同。北段滑脱强度大,为大规模由隆起向坳陷(由西向东)逆冲的推覆构造型式,而南段滑脱强度相对较小,为两侧向向斜中部对冲的推覆构造型式。究其原因,除公认的软硬岩层相间、隆起坳陷的位能差异原因外,还认为北段的宽缓波状带、南段的向背斜序列带以及北西走滑性断裂的分割作用是造成该推覆、滑脱活动迥异的基本因素。研究这些规律,对福建省新一轮找煤工作有重要的指导作用。  相似文献   

11.
A belt of low-angle normal (or detachment) faults ~250 km long extends from the northern end of the Salton Trough, California to southern Laguna Salada, Baja California, Mexico. The detachment system is divided into two principal segments. The northern segment, here termed the “west Salton detachment system,” comprises top-to-the-east detachment faults along the eastern Peninsular Ranges that root under the Salton Trough. The southern segment, here termed the Laguna Salada detachment system, comprises top-to-the-west detachment faults in northeastern Baja California and the Yuha Desert region of the southwesternmost Salton Trough. Detachments of that system root under Laguna Salada and the Peninsular Ranges of northern Baja California. Both of these systems experienced a major episode of activity in late Miocene to Pleistocene time, synchronous with deposition of the Imperial and Palm Spring formations, and the Laguna Salada detachment system may still be active. Thus, their activity temporally overlapped, partly or completely, with activity on dextral faults of the San Andreas boundary between the Pacific and North American plates, and with accretion of new transitional crust. Some of the detachment faults in the northern segment may have had mid-Miocene normal slip and/or Cretaceous thrust or normal slip as well, although compelling evidence for either is lacking. These detachment faults are distinctly younger than detachments east of the San Andreas fault, which generally ceased activity by middle or late Miocene time and are overlapped by marine or lacustrine rocks (Bouse Formation); these units are equivalent in age to the syntectonic strata of the Salton Trough but are much thinner and essentially undeformed.  相似文献   

12.
Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation:zonation,segmentation and stratification.Zonation means that,from NW to NE,the Longmen Mountain Thrust Belt can be divided into the Songpan- Garz(?) Tectonic Belt,ductile deformation belt,base involved thrust belt,frontal fold-thrust belt,and foreland depression.Segmentation means that it can be divided into five segments from north to south: the northern segment,the Anxia...  相似文献   

13.
Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth's surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where detachment is expected. In this study, we quantify surface deformation caused by detachment of subducted lithosphere. We determine the range of displacement magnitudes which can be associated with slab detachment using numerical models. The lithospheric plates in our models have an effective elastic thickness, which provides an upper bound for rapid processes, like slab detachment, to the surface deformation of lithosphere with a more realistic rheology. The surface topography which develops during subduction is compared with the topography shortly after detachment is imposed. Subduction with a non-migrating trench system followed by detachment leads to a maximum surface uplift of 2–6 km, while this may be higher for the case of roll-back preceding detachment. In the latter situation, the back-arc basin may experience a phase of compression after detachment. Within the context of our elastic model, the surface uplift resulting from slab detachment is sensitive to the depth of detachment, a change in friction on the subduction fault during detachment and viscous stresses generated by sinking of the detached part of the slab. Overall, surface uplift of these magnitudes is not diagnostic of slab detachment since variations during ongoing subduction may result in similar vertical surface displacements.  相似文献   

14.
Field investigation and seismic section explanation showed that the Longmen Mountain Thrust Belt has obvious differential deformation: zonation, segmentation and stratification. Zonation means that, from NW to NE, the Longmen Mountain Thrust Belt can be divided into the Songpan-Garzê Tectonic Belt, ductile deformation belt, base involved thrust belt, frontal fold-thrust belt, and foreland depression. Segmentation means that it can be divided into five segments from north to south: the northern segment, the Anxian Transfer Zone, the center segment, the Guanxian Transfer Zone and the southern segment. Stratification means that the detachment layers partition the structural styles in profile. The detachment layers in the Longmen Mountain Thrust Belt can be classified into three categories: the deep-level detachment layers, including the crust-mantle system detachment layer, intracrustal detachment layer, and Presinian system basal detachment layer; the middle-level detachment layers, including Cambrian-Ordovician detachment layer, Silurian detachment layer, etc.; and shallow-level detachment layers, including Upper Triassic Xujiahe Formation detachment layer and the Jurassic detachment layers. The multi-level detachment layers have a very important effect on the shaping and evolution of Longmen Mountain Thrust Belt.  相似文献   

15.
南海北部珠江口盆地中段伸展构造模型及其动力学   总被引:1,自引:0,他引:1  
位于南海北部大陆边缘上的珠江口盆地发育NNE向、NE向、NW向、近EW向等多组基底断裂,盆地结构复杂,并表现出明显的时空差异性。本文基于珠江口盆地中段地震资料解释的构造样式的变化推断地壳中存在一条向南缓倾斜、呈坡坪式形态的拆离断层,古近系构造属于这条拆离断层上盘的伸展构造系统。北部的西江凹陷属于拆离断层伸展构造系统的头部,凹陷边界正断层铲式断层面形态向深层延伸并收敛在拆离断层面上,凹陷表现为半地堑“断陷”样式;中部的番禺低隆起对应于拆离断层的低角度断坪部位,拆离断层上盘断块的伸展位移导致两侧的恩平组超覆在低隆起上;南部的白云凹陷位于拆离断层的深部断坡部位,充填的文昌组和恩平组表现为“断坳”或“坳断”样式;南部隆起位于拆离断层深部断坪部位,其上盘发育的分支断层控制着荔湾凹陷古近系、新近系的发育并使之表现为复杂的断陷断坳构造样式。该模型强调拆离断层上盘与下盘、不同地壳结构层均发生不同程度的伸展变形,且伸展变形方式、应变量等存在时空差异,而拆离断层正是不同构造单元、不同地壳构造层之间的调节性构造面。总体上,拆离断层上盘以脆性伸展构造变形为主,分支断层控制不同构造单元古近纪的构造演化,下盘则是以韧性伸展变形为主,并拖曳上盘发生不均一的伸展应变;西江凹陷的伸展应变量大于拆离断层下盘的伸展应变量,白云凹陷的伸展应变量则小于拆离断层下盘的伸展应变量。以西江凹陷北部边缘的NE向铲式正断层为头部的拆离断层控制了文昌组沉积,但在恩平组沉积期被近EW向高角度正断层切割破坏而被遗弃,拆离断层系统的头部由西江凹陷北部边缘迁移至番禺低隆起。盆地结构及断裂系统的时空差异性受盆地基底先存构造、地壳与岩石圈结构及伸展量等多方面因素的影响,但主要是对软流圈流动及岩石圈热结构变化的响应。用软流圈由北西向南东流动拖曳上覆岩石圈发生伸展变形的动力学模型能合理地解释珠江口盆地中段古近系构造的形成和演化。  相似文献   

16.
喜马拉雅造山带中段定结地区拆离断层   总被引:1,自引:1,他引:1  
定结地区位于喜马拉雅造山带中段,发育大量的低角度伸展拆离断层,这些拆离断层中部分构成了藏南拆离系的主体。它们基本上垂直于造山带走向伸展,各拆离断层特征显著,普遍发育糜棱岩,糜棱岩类型复杂,主要有硅质糜棱岩、长英质糜棱岩、花岗质糜棱岩。在研究区的北部,拆离断层呈环状产出,构成变质核杂岩三层结构中的中间层,规模一般较大;同时拆离断层使变质核杂岩体盖层中的部分地层拆离减薄;在研究区南部拆离断层呈线状延伸很远,总体上平行造山带延伸,构成了藏南拆离系重要组成部分。部分拆离断层同韧性剪切带平行产出,形成拆离剪切的脆韧性体系。  相似文献   

17.
The Louzidian metamorphic core complex (LMCC) in southern Chifeng is located on the northern margin of the North China craton. Structural analyses of the LMCC and its extensional detachment system indicate that the LMCC experienced two-stage extension. The ductile regime experienced top-to-northeast shearing extension and the brittle detachment fault underwent top-down-outwards slipping. Between these two stages, a semi-ductile regime recorded the transition from ductile to brittle. The hanging wall of the detachment fault is similar to those classic supradetachment basins in western North America. Analyses of provenance and paleocurrent directions in the basins show that there were two filling stages. In the early stage, materials came from the southwest margin of the basin and the hanging wall of the detachment system and were transported from southwest to northeast; while in the late stage, deposits were derived from the footwall of the detachment fault and transported outwards to the two sides of the  相似文献   

18.
西沙海域夹持于南海西北次海盆和西南次海盆之间,构造演化过程与南海的扩张和南海西部的走滑作用关系密切.基于覆盖西沙海域的区域地震资料开展了构造—地层解释、盆地结构特征分析和区域构造演化制图,整体上将西沙海域划分出3种类型盆地,即高角度断层控制的盆地、低角度拆离断层控制的盆地和走滑盆地.结合地壳厚度变化和伸展薄化程度,突出断层的构造样式,将西沙海域划分为北部拆离断层构造发育区、东南部拆离断层构造发育区、西部走滑断层发育区和中部高角度断层发育区,进而明确了西沙海域盆地的基本构造格局.同时,以关键构造界面为主线,强调了不同类型断层在岩石圈地壳减薄过程中的作用,阐明了西沙海域盆地的差异构造演化过程.   相似文献   

19.
对青海锡铁山矿区几个关键地质问题的认识   总被引:6,自引:0,他引:6  
锡铁山矿区晚奥陶世滩间山群与早元古代达肯大坂群间的接角关系为隐蔽不整合,其间发育基底剥离断层(F1),基底剥离断层之下的“过渡带”实际上是一条退条质的下滑型韧性剪切带。而滩间山群则被构造肢解为O3tm^a-b褶叠层与O3tn^c-d褶皱冲断岩片,其间发育上剥离断层(F2),两条剥离断层面上、下因构造剥蚀充失了大厌地层。并认为和里东晚期的伸展构造体制形成锡铁山变质核杂岩,海西期的抗日压构造体制形成褶  相似文献   

20.
珠江口盆地新生代发育跨越浅水区至深水区、多类型的拆离断陷,其中浅水陆架区拆离断陷是探究拆离构造变形与沉积充填响应的重要窗口.基于地震资料和钻井资料详细解析,对恩平凹陷低角度拆离断层特征进行了研究,探讨了拆离构造变形的控制因素、变形过程和沉积充填响应机制.研究表明,恩平凹陷低角度边界正断层为壳间拆离断层,长度约50 km,倾角平均17.5°,断面最深达中下地壳,裂陷期经历了中低角度到低角度的转变.拆离断层形成于中生代先存逆冲断层基础之上,与中下地壳韧性剪切穹隆和边界调节性走滑断裂相伴生,联合控制形成均衡深拆离、前展式宽拆离和迁移型复式拆离3种凹陷结构类型.垂向上可划分出三期裂陷幕,因差异构造变形而具有不同的沉积充填响应:(1)早文昌期均一裂陷幕,快速的裂陷沉降发育于先存逆冲断层弱面,形成具厚层中深湖的均一窄深箕状半地堑;(2)晚文昌期拆离伸展幕,凹陷受差异构造变形而发育成东、西沉积充填差异化的宽浅断陷,西部韧性剪切穹隆弱隆升与边界走滑断层强走滑控制了恩平17洼自迁移型中深湖和大型辫状河三角洲-重力流沉积,而东部韧性剪切穹隆强隆升控制了恩平12-18洼沉积中心跳跃式异迁移的沉积充填,过渡带发育大型走向斜坡扇三角洲;(3)恩平期拆离-断拗联控幕,构造变形由简单剪切向纯剪切转变,沉积向外流水系主导的浅水辫状河三角洲-浅湖相充填转变.低角度拆离断陷具有与高角度脆性断陷不同的构造变形和沉积充填响应,烃源岩与砂岩储层的时空分布非均质性强.研究成果对恩平凹陷的烃源岩和深部储层预测,以及南海北部陆缘同类拆离断陷的构造-沉积充填研究具有良好的指导意义.   相似文献   

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