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1.
藏南隆子—措美一带夹持于藏南拆离系(STDS)和雅鲁藏布江缝合带(IYS)之间。印度与欧亚大陆的碰撞作用形成了该地区特殊的构造样式,由近东西向展布的藏南拆离系主拆离带和洛扎、绒布—隆子两条断裂带、一系列倒转复式褶皱以及两个穹窿构造组成。始喜马拉雅期印度板块与欧亚大陆发生大规模陆—陆碰撞,导致特提斯喜马拉雅前陆盆地发生大规模缩短,沉积盖层以藏南拆离系为底界自北向南大规模逆冲推覆、褶皱;新喜马拉雅期高喜马拉雅结晶岩系自北向南挤出;藏南拆离系主拆离带和洛扎、哲古两条次级构造带上盘地层是自南向北伸展的产物。  相似文献   

2.
青藏高原东西向伸展及其地质意义   总被引:30,自引:4,他引:30  
张进江  丁林 《地质科学》2003,38(2):179-189
东西和南北向伸展是青藏高原最显著的地质特征之一。南北向伸展形成的东西走向伸展构造,主要包括藏南拆离系(STDS),和沿喀喇昆仑—嘉黎断裂带(KJFZ)发育的正断层体系。东西向伸展形成数目众多的南北走向伸展构造,它们切割青藏高原几乎所有的东西走向构造单元,包括羌塘地块、KJFZ和STDS等,说明东西向伸展以整体形式发生并同时波及整个青藏高原,而不是由以KJFZ和STDS为边界的不同地块的不均匀挤出所致。南北走向伸展构造在地表呈之字形,为南北向挤压形成的追踪张断裂;剖面上表现为被后期高角度正断层叠加的拆离断层,拆离断层形成于中-晚中新世而高角度正断层形成于上新世及以后。导致拆离断层的东西向伸展可能是南北向挤压的变形分解,后期高角度正断层作用可能是高原隆升后的垮塌所致。东西向伸展是控制青藏高原新生代浅色花岗岩和盆地形成的主要因素。  相似文献   

3.
西藏洛扎地区拆离断层构造变形特征   总被引:7,自引:3,他引:4  
西藏洛扎地区发育的拆离断层叠加在先期逆冲推覆构造之上,并被以脆性变形为特征的高角度北倾正断层改造,各阶段变形结构面交切关系清楚。拆离活动表现为韧性-韧脆性层间剪切,拆离体依次向北西(北北西)近水平左行滑断。与韧性拆离断层具有成生关系的淡色花岗岩产状特征及年代学研究表明,拆离断层变形时代为中新世中晚期。本文着重阐述拆离断层几何学及运动学特征,并根据地球物理场资料所反映的青藏高原深部结构特征讨论其成因。  相似文献   

4.
黄骅盆地南部前第三系基底中的逆冲构造   总被引:12,自引:0,他引:12  
黄骅盆地南部前第三系构造层中广泛发育有逆冲构造.其中西部的逆冲构造带以逆冲堆叠背形构造和逆冲叠瓦扇构造为主, 中部以楔冲双重构造和低角度盲冲或顺层滑脱构造为主, 东部以高角度板状逆冲叠瓦构造为主.这些逆冲构造带都表现为由SE向NW-MNW方向的逆冲, 而且由构造样式推测的拆离滑脱深度是由西向东逐渐加深, 表明在深层可能有一条向南东倾斜的拆离断层将它们连锁在一起, 构成统一的逆冲构造系统.从卷入逆冲构造的地层的地质时代推测, 逆冲构造主要是在早—中三叠世盆地发育之后、侏罗—白垩纪盆地形成之前形成的, 并在早—中侏罗世盆地发育过程中又有进一步活动.逆冲构造形成后又受到中—新生代时期的伸展构造和走滑构造的叠加和改造.控制黄骅盆地老第三纪伸展盆地的形成和演化的沧东断层的某些地段, 在前第三纪时期曾经是一条逆冲断层.   相似文献   

5.
塔里木盆地西北缘柯坪逆冲构造带与巴楚隆起的叠加关系   总被引:2,自引:0,他引:2  
杨庚  郭华 《铀矿地质》2003,19(1):1-7
塔里木盆地西北缘柯坪逆冲带是天山和塔里木盆地在新生代盆山耦合作用下形成的构造变形区,为印度板块和 欧亚板块碰撞所影响的最明显地区之一。柯坪逆冲带逆冲方向是从天山向塔里木盆地内逆冲,构造变形样式是以寒武系蒸发岩层为滑动拆离面的薄皮构造,也有卷入前寒武系-元古界结晶基底的逆冲推覆构造,以及北西向走滑断层。以皮羌断层和印干断层为界,根据构造样式的差异,柯坪逆冲带可分为3个构造区,即西克尔区、柯坪区和阿克苏区。西克尔区逆冲推覆构造卷入地层厚度大,基底拆离面深度为7-8km;柯坪区逆冲推覆构造卷入地层厚度小,基底拆离面深度为5-6km;阿克苏区则为卷入前寒武系结晶基底的逆冲推覆构造。这些构造样式的差异是由于北西向的巴楚隆起对近北东走向的柯坪逆冲构造带叠加的结果,尤其巴楚隆起的南界--皮羌高角度逆冲断层与柯坪逆冲带发育的皮羌左旋走滑断层,以及巴楚隆起的北界--印干逆冲断层与柯坪逆冲带发育的印干右旋走滑断层对柯坪冲构造带的叠加最为明显。  相似文献   

6.
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   

7.
黔南地区古生代正断层对构造特征的制约   总被引:2,自引:1,他引:1  
黔南地区发育东西向的古生代正断层以及南北向的中、新生代逆冲断层和褶皱。通过对地层、褶皱和断层的平面展布、野外地质调查以及地震剖面的解释,结合雪峰隆起的逆冲推覆特征,研究黔南地区古生代正断层对构造特征的制约作用。研究结果表明东西向的古生代正断层在中、新生代的构造变形过程中起构造转换带的作用。通过建立区内构造转换带的几何学模型,对地震线上的构造变形特征进行了解释。在构造转换带(正断层)附近,断层上盘逆冲推覆不明显;在远离断层处,逆冲断层和与断层相关的褶皱发育。随着距离断层面越来越远,构造转换带(正断层)下盘地层的逆冲推覆特征逐渐消失。  相似文献   

8.
结合区域地质资料和前人资料,深入研究了闽西推覆构造带前峰处的苏桥-小溪洋井田地质特征。结果显示:井田剖面几何形态为一典型的"仑"型背骑式逆冲推覆构造;逆冲推覆构造和层间拆离滑覆构造是井田两种基本的构造类型;层间拆离滑覆构造形成于早印支期,逆冲推覆构造主要形成于燕山早期、燕山晚期和喜山期;井田在区域拉张环境下遭受剥蚀改造,发育飞来峰构造,并使F5、F6断层产生反转。从而,在构造推覆体下找煤应特别注意地层缺失情况,区域隐伏煤田的预测应采用物探与钻探相结合的方法。  相似文献   

9.
天湖山煤矿区经历多期次的构造演化,广泛发育了以推覆、滑覆断层为主的控煤构造。为加深对推覆、滑覆叠加构造控煤机制的认识,在掌握区域地质背景的基础上,结合几何学、运动学和动力学研究天湖山典型推覆、滑覆构造的形成与演化,以及推滑叠加型构造对煤层的控制作用。结果表明:区内构造先后经过了多期次、多层次伸展滑覆和逆冲推覆的复杂叠加作用,推滑叠加型构造的控煤机制主要体现两个方面:1滑覆断层的伸展应力环境和剥蚀效应造成地层的缺失;2推覆断层挤压应力环境以及地层增厚效应造成地层的重复和抬升,另外叠加构造也导致煤层发生流变。  相似文献   

10.
利用地震资料、油气勘探资料分析了南海北部大陆边缘珠江口-琼东南新生代盆地断裂系统的时空差异及动力学成因机制.珠江口-琼东南盆地古近系裂陷构造层以NE向、近EW向基底正断层构成的伸展断裂系统的几何学、运动学沿着盆地走向有明显变化,盆地内部隐伏的区域性和局部的NW向断裂及相关构造变形带构成伸展断裂系统之间的构造变换带.在空间上,区域性的云开、松涛-松南等NW向构造变换带以西为NE-NEE向正断层构成的"非拆离"伸展断层系,以东为NE向正断层、近EW向正断层(走滑正断层)复合而成的拆离伸展断层系.在时间上,古近纪裂陷作用可划分为早(文昌组沉积期)、中(恩平组/崖城组沉积期)、晚(珠海组/陵水组沉积期)3个有明显差异的裂陷期.裂陷早期,盆地西部以平面式正断层控制的简单地堑、半地堑为主,伸展量相对较小,东部则以铲式正断层控制的复式地堑、半地堑为主,伸展量相对大,断层向深部收敛在中地壳韧性层构成拆离的伸展断层系统.裂陷中期,琼东南盆地、珠江口盆地西部断裂具有继承性活动特点,珠江口盆地东部发育NWW-EW向伸展断层,并向深层切割早期浅层拆离断层,形成深层拆离伸展断层系统,而沿着云开构造变换带发育反转构造.裂陷晚期,琼东南盆地、珠江口盆地西部断裂具有活动性减弱特点,琼东南盆地东部发育NWW-EW向伸展断层,形成深层拆离伸展断层系统,而沿着琼中央构造变换带发育反转、走滑构造.珠江口-琼东南盆地不同区段断裂系统及其构造演化的差异性受盆地基底先存构造、地壳及岩石圈结构及伸展量等多方面因素的影响,拆离伸展断层系统与发育NWW向"贯穿"断裂的基底构造薄弱带、现今地壳局部减薄带相关,南海扩展由东而西的迁移诱导北部大陆边缘块体沿着先存NW向深大断裂发生走滑旋转是导致变换构造带两侧差异伸展的动力学原因,应力场及岩石圈热结构变化是引起拆离断层深度变化的重要因素.  相似文献   

11.
Opening-closing tectonics is a new idea for exploring the global tectonics, which holds that every tectonic movement of all materials and geological bodies on earth is characterized by opening and closing. The opening -closing tectonic view can be used to explain some geological phenomena developing in continents which cannot be reasonably explained by the theory of plate tectonics. Based on the available basic geological data and combining with the opening-closing view, we analyzed the divisions and characteristics of tectonic units in South Tibet, and propose that Tibet can be divided into gravitational detachment and detachment fault zones, which are superimposed thrust fault zones and reconstructed normal fault zones, respectively. Although the mainstream opinion believed that the Tibetan Plateau is formed by collision-compression orogenesis, field investigation revealed the existence of the Rongbu Temple normal fault in the1970s. We consider that the Rongbu Temple normal fault and the Main Central Thrust (MCT) were formed earlier than the South Tibet detachment fault, and the former two faults constitute the two boundaries of the southern Tibet extrusion structure. The South Tibet detachment fault partially superimposes on the MCT and manifests a relatively high angle in following the Rongbu Temple normal fault north of the Chomolangma. We suggest that the three fault systems are the products of different periods and tectonic backgrounds. The tectonic units, such as klippes and windows identified by previo us researchers in southern Tibet, belong to thrust fault system but usually have no obvious extrusion or thrust characteristics; however, they are characterized by missing strata columns as younger strata overlapping the older ones. These klippes and windows should be the results of later gravitational decollement and must be characterized as extensions and slips, respectively. Based on opening-closing theory, we suggest that since the Cenozoic the study area had undergone multistage development, which can be divided into the oceanic crust expansion (opening) and subduction (closing) and the continental collision (closing) and intracontinental extension (opening) stages. Geothermal energy from the deep earth, gravitational potential energy from the earth’s interior, and additional stress energy from tectonic movements, all played a key role in the multistage tectonic evolutionary process.  相似文献   

12.
藏北改则新生代早期逆冲推覆构造系统   总被引:2,自引:0,他引:2  
藏北改则及邻区新生代早期发育大型逆冲推覆构造系统,由不同方向的逆冲断层、不同时代的构造岩片、不同规模的飞来峰和构造窗、不同类型的褶皱构造组成。羌塘中部发育羌中薄皮推覆构造,石炭系板岩和二叠系白云质灰岩自北向南逆冲推覆于上白垩统与古近系红层之上,形成大型逆冲岩席和弧形逆冲断层,原地系统古近纪红层下伏三叠系—侏罗系海相烃源岩。羌塘南部发育南羌塘薄皮推覆构造,导致班公—怒江蛇绿岩、三叠系—侏罗系海相地层及侏罗纪混杂岩自北向南逆冲推覆于古近纪红层与下白垩统海相沉积岩层之上,形成三条蛇绿岩片带、大量飞来峰和厚度较大的构造片岩。中新世早期火山岩层和湖相沉积呈角度不整合覆盖逆冲断层、褶皱构造和逆冲岩席,不整合面上覆火山岩年龄为23.7~19.1Ma,指示中新世早期改则及邻区基本结束了强烈逆冲推覆构造运动。估算羌中逆冲推覆构造的推覆距离约100~115km,南羌塘逆冲推覆构造的推覆距离约82~110km;新生代早期改则逆冲推覆构造系统近南北方向逆冲推覆总距离为182~225km,对应地壳缩短率为(50.3±2.7)%。  相似文献   

13.
湘东北煤田构造复杂,主要表现为褶皱和断裂,尤以逆冲推覆和滑覆构造较为发育,多期次的构造叠加、切割及剥蚀,呈现构造窗和飞来峰,使含煤岩系在平面上零星分布。探讨本区滑脱构造发育的区域地质背景,运用推覆构造理论深入分析了引起逆冲推覆构造和滑覆构造的形成机制,对掌握煤炭资源分布规律、评价湖南煤炭资源潜力有一定的指导意义。  相似文献   

14.
We assume that great and moderate Himalayan earthquakes occur through reactivation of subhorizontal thrust faults by frictional failure under the action of stresses induced by Himalayan topography, isostasy related buoyancy forces, crustal overburden and plate tectonic causes. Estimates of stresses are based on two dimensional plane strain calculations using analytical formulae of elasticity theory and rock mechanics under suitable simplifying assumptions. Considerable attention is focussed on a point on the detachment at a depth of 17 km below mean sea level under the surface trace of the Main Central Thrust (MCT). According to recent views, great Himalayan earthquakes should nucleate in the detachment in the vicinity of such a point. Also many moderate earthquakes occur on the detachment similarly under the MCT. Vertical and horizontal normal stresses of 622 and 262 MPa and a corresponding shear stress of 26 MPa are estimated for this point due to topography, buoyancy and overburden. For fault friction coefficient varying between 0.3 to 1.0, estimates of plate tectonic stress required are in the range of 386 to 434 MPa, when the cumulative principal stresses are oriented favourably for reactivation of the detachment. Estimates of shear stress mobilized at the same point would be from 27 to 32 MPa for the identical range of fault friction coefficient. Our calculations suggest that presence of pore water in the fault zones is essential for reactivation. Pore pressure required is between 535 to 595 MPa for friction coefficient in the range of 0.3 to 1.0 and it is less than lithostatic stress of 603 MPa at the above point. For the specific nominal value of 0.65 for fault friction coefficient, the estimated values of plate tectonic stress, shear stress and pore pressure at the above point on the detachment are 410 MPa, 30 MPa and 580 MPa respectively. Similar estimates are obtained also for shallower points on the detachment up to the southern limit of the Outer Himalaya. Our estimates of the plate tectonic stress, shear stress and pore pressure for reactivation of upper crustal thrust faults compare favourably with those quoted in the literature.  相似文献   

15.
造山带挤出构造   总被引:14,自引:0,他引:14  
挤出构造模式已经从二维变形进入三维变形研究,在喜马拉雅造山带,高喜马拉雅结晶地体沿北倾的主中央逆冲断层和北倾 的绒布寺正断层,表现为相对刚性体之间的韧性体的楔状挤出。非连续介质大变形有限元数值模拟结果为这一模式提供了力学依据。在前人工作的基础上,提出了东阿尔卑斯三维管状挤出模式,将上部脆性层划分出北部左行平移带,南部右行平移带和中部挤出楔,中部韧性层在南阿尔卑斯和欧洲前陆碰撞过程中,既有垂向挤出,也有侧向挤出,在平行缩短方向的剖面上,由箱状背形隆起演化成逆-逆断层组合的楔状挤出,形成三角断面的管状,在垂直缩短方向的剖面上,中部韧性层呈不均匀流动,形成管状层流-韧性层中心为纯剪切,上部和侧部为简单剪切,在陕甘川邻接区,由于祁连山-北秦岭加里东喧向南的推挤和川西前陆的刚性阻挡,造成西秦岭和东松潘-甘孜复合造山体的三维滑脱挤出,以北西西向玛曲-略阳滑脱逆冲断裂和北东向青川一茂县滑脱逆冲断裂为界,将陕甘川邻接区的三维滑脱挤出复合造山体划分为西秦岭滑脱挤出带,摩天岭0若尔盖滑脱挤出楔和龙门山滑脱挤出逆冲椎覆带,以近南北向岷江滑脱逆冲断裂为界将滑脱挤出楔进一步划分成摩天岭滑脱挤出体和苦尔盖滑脱挤出体,除了不同构造单元的不均匀隆升外,摩天岭还表现出向西的侧向挤出。  相似文献   

16.
A system of left-lateral faults that separates the South American and Scotia plates, known as the Magallanes-Fagnano fault system, defines the modern tectonic setting of the southernmost Andes and is superimposed on the Late Cretaceous – Paleogene Patagonian fold-thrust belt. Fault kinematic data and crosscutting relationships from populations of thrust, strike-slip and normal faults from Peninsula Brunswick adjacent to the Magallanes-Fagnano fault system, presented herein, show kinematic and temporal relationships between thrust faults and sets of younger strike-slip and normal faults. Thrust fault kinematics are homogeneous in the study area and record subhorizontal northeast-directed shortening. Strike-slip faults record east—northeast-directed horizontal shortening, west—northwest-directed horizontal extension and form Riedel and P-shear geometries compatible with left-lateral slip on the main splay of the Magallanes-Fagnano fault system. Normal faults record north-south trending extension that is compatible with the strike-slip faults. The study area occurs in a releasing step-over between overlapping segments of the Magallanes-Fagnano fault system, which localized on antecedent sutures between basement terranes with differing geological origin. Results are consistent with regional tectonic models that suggest sinistral shearing and transtension in the southernmost Andes was contemporaneous with the onset of seafloor spreading in the Western Scotia Sea during the Early Miocene.  相似文献   

17.
库车坳陷盐下构造对盐上盖层变形的影响因素分析   总被引:1,自引:0,他引:1       下载免费PDF全文
库车坳陷是在地壳或者岩石圈尺度整体挤压作用下,收缩构造变形形成的一个构造单元,膏盐岩层等软弱岩层可能导致滑脱断层发育,并引起盐上和盐下不协调收缩变形,区域挤压作用下一些先存基底断裂带的逆冲位移是控制盐上层冲断褶皱变形的主要因素。运用地震资料、地表露头、钻测井资料以及非地震资料等,对库车坳陷区域大剖面的盐上层、盐下层的构造变形样式进行分析,认为南天山在挤压收缩变形中隆升,诱导盆山过渡带发育基底卷入的高角度逆冲断层,先前基底断层的复活影响了盆地沉积盖层的构造变形,基底断裂与盖层断层组合样式在走向上基本一致,盖层强变形带与基底断裂带上下呼应。  相似文献   

18.
Abstract Geological relationships and geochronological data suggest that in Miocene time the metamorphic core of the central Himalayan orogen was a wedge-shaped body bounded below by the N-dipping Main Central thrust system and above the N-dipping South Tibetan detachment system. We infer that synchronous movement on these fault systems expelled the metamorphic core southward toward the Indian foreland, thereby moderating the extreme topographic gradient at the southern margin of the Tibetan Plateau. Reaction textures, thermobarometric data and thermodynamic modelling of pelitic schists and gneisses from the Nyalam transect in southern Tibet (28°N, 86°E) imply that gravitational collapse of the orogen produced a complex thermal structure in the metamorphic core. Amphibolite facies metamorphism and anatexis at temperatures of 950 K and depths of at least 30 km accompanied the early stages of displacement on the Main Central thrust system. Our findings suggest that the late metamorphic history of these rocks was characterized by high- T decompression associated with roughly 15 km of unroofing by movement on the South Tibetan detachment system. In the middle of the metamorphic core, roughly 7–8 km below the basal detachment of the South Tibetan system, the decompression was essentially isothermal. Near the base of the metamorphic core, roughly 4–6 km above the Main Central thrust, the decompression was accompanied by about 150 K of cooling. We attribute the disparity between the P–T paths of these two structural levels to cooling of the lower part of the metamorphic core as a consequence of continued (and probably accelerated) underthrusting of cooler rocks in the footwall of the Main Central thrust at the same time as movement on the South Tibetan detachment system.  相似文献   

19.
克拉苏构造带位于库车坳陷与南天山盆山过渡带,特殊的受力环境使其构造变形机制具有特殊性。依据最新的地震和钻井资料,并结合前人研究成果,建立了克拉苏构造带新的地震解释方案,并据此分析该地区盐上、盐下层构造变形几何形态、演化过程、形成机制等方面的差异及其控制因素。结果表明:克拉苏构造带盐下层构造变形可分为两部分,包括由基底卷入的高角度正断层后期挤压形成的反转断裂系统,以及主断裂下盘发育的次生盖层滑脱逆冲叠瓦断裂系统。盐上层构造变形为褶皱相关断层,其演化经历了基底断裂向上传递形成传播褶皱、差异压实作用诱发底辟褶皱、以及褶皱核部在持续挤压作用下形成破冲断层等多个阶段。盐下层基底卷入断裂系统形成于侏罗纪盆山过渡带伸展环境,而叠瓦式盖层滑脱断裂系统和盐上层构造变形主要形成于中新世-第四纪的挤压构造环境。盆山过渡带特殊的构造部位及在不同地质时期应力场的转换控制了盐下层构造变形机制,而盐上层构造变形受到基底断裂复活、差异沉积负荷、膏盐岩底辟上涌、挤压应力增强以及北部山前地形高差等众多因素影响,且不同演化阶段主控因素有所差异。克拉苏构造带盐下、盐上层变形机制和毗邻区带相比有较大差异,这与其特殊的构造位置以及构造应力在盐下和盐上地层向前陆方向传递的方式和距离不同等因素有关。  相似文献   

20.
通过选取南黄海盆地中部隆起内部地震反射清晰、构造特征明显的典型地震剖面,开展精细的构造解释,系统梳理了南黄海盆地中部隆起的构造样式特征,识别出挤压(滑脱、高角度逆冲、对冲/背冲)、走滑(正花状、y字型)、伸展(铲式正断层)等多种构造组合样式.首次提出在中部隆起内部发育2条NW-SE向走滑断层.在此基础上,结合区域应力场特征和深部地球动力学背景,明确了中部隆起构造样式的发育期次、成因机制和构造演化历程.研究结果表明:(1)滑脱构造主要位于中部隆起北部,滑脱面位于志留系底部的泥页岩.滑脱构造应力机制来源于三叠纪末印支运动时期华北板块与下扬子板块之间的碰撞造山作用;(2)高角度逆冲主要位于中部隆起南部,其应力机制来源于早侏罗世燕山运动早期,古太平洋板块初始高速、低角度NW向俯冲;(3)走滑断层主要表现为具有压扭特征的正花状构造,位于中部隆起东南部、中西部,对应于早白垩世时期,古太平洋板块低角度俯冲由NW向转变为NNW向引起的左旋剪切作用,中国东部郯庐断裂在该时期亦表现为左旋剪切特征;(4)伸展正断表现为铲式正断层特征,发育在中部隆起南北边界,即在中部隆起与南黄海盆地南部坳陷、北部坳陷的接触部...  相似文献   

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