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1.
Chen Qiang 《《地质学报》英文版》1988,62(2):127-140
Listric faults of different levels and scales are widely developed in the lithosphere. According to theirtectonomechanical geneses. the author divides listric faults into primary and secondary ones. and the formermay be subdivided into gravity-gliding listric faults, regional extensional listric normal faults. regionalcontractional reverse listric faults and deep-seated ductile listric faults, By means of the slip-line field theorydealing with Mohr's criterion expressed by quadratic limiting curves. the author has preliminarily determinedthe occurrences. patterns and mechanical properties of various types of listric faults during their formation. andhas analyzed their tectonic evolution and related dynamic processes in the lithosphere. 相似文献
2.
《International Geology Review》2012,54(11):967-982
We present an outcrop-scale example of a localized contractional fault geometry that developed as part of an imbricate normal fault system in response to regional extension. Although extensional regions are dominated by abundant normal faulting, local thrust duplication may occur during the same phase of deformation, and on a regional scale may concentrate important quantities of hydrocarbons. Characteristics of extension-related fold belts have mostly been derived from seismic sections; thus fault geometries, mechanisms of formation, and kinematics of these structures are not precisely understood. Abundant kinematic indicators and complete exposure of an extended sedimentary sequence within the Dead Sea Transform, however, provide the opportunity to examine these fault geometries and mechanisms in detail. The local contractional geometry developed within an imbricate normal fault system, as a result of an out-of-sequence normal fault that detached at a higher structural level. The out-of-sequence normal fault offset pre-existing faults, but was deflected into a contractional geometry upon encountering an earlier-formed rollover anticline, whose curved bedding surface served as a convenient ramp. Consequently, displacement across the out-of-sequence fault generated coeval extensional and contractional geometries along the same detachment surface. Geometries and kinematics derived from the outcrop structural analysis may serve as important analogs for larger structures identified as potential targets for hydrocarbon exploration. 相似文献
3.
The tectonics of the central Aeolian Islands, which are located within the Tyrrhenian backarc basin, has been investigated through a marine seismic reflection survey. We find that compressional structures dominate around the islands, whereas extensional faults occur only to the north of Salina and Filicudi, towards the Marsili basin. This pattern of deformation, although different from previously reported, is in agreement with the strain field and stress regime obtained from GPS measurements and seismological data. Age constraints suggest that contractional deformation was active since middle Pleistocene, being coeval with the building of the volcanic edifices of the Aeolian Islands, and is superimposed on pre‐existing extensional deformation. Compressional and extensional regimes, therefore, can coexist within a backarc setting. Seismic profiles show that the Tindari‐Letojanni fault, considered as a major tectonic element, does not extend to the north towards the island of Vulcano as a throughgoing fault; rather, deformation is accommodated in a broader belt displaying greater structural complexity. 相似文献
4.
M.P Coward 《Journal of Structural Geology》1982,4(3):247-256
The Caledonian thrust zones of Assynt show several examples of large fault-bounded structures, surge zones, up to 8 km2 in extent, which have moved further than adjacent rocks. Extensional faults can be traced into strike-slip faults and then to contractional imbricate faults. There are also zones of extensional and contractional flow as shown by strained bioturbation marks in the Cambrian Pipe Rock.Several other low-angle extensional fault zones have been recognized along the length of the Moine thrust zone, notably in the Kinlochewe district. Recognition of these extensional faults and local surge zones has solved several local problems such as the lack of continuity of the Glencoul thrust and the out-of-sequence character of some of the large low-angle faults. Though the thrust propagation direction was generally from east to west, in the transport direction, several of the eastern faults have been reactivated later and locally cut down as extensional faults. The ‘so-called’ Moine thrust shows extensional fault movement at several localities along its length.The extensional structures and the surge zones suggest that body forces have been important in driving the faults rather than just a push from the rear. The Moines and Moine thrust zone were presumably driven to the WNW by gravity spreading and thinning of the main Scottish Caledonides. 相似文献
5.
《Geodinamica Acta》2013,26(3):145-167
Folds constitute a significant part within the dominantly extension-related deformation pattern of the Gediz Graben and their origin either extensional or contractional has been the subject of debate. Field and subsurface data presented in this paper suggest that folds of contractional and extensional origin coexist in the graben-fill sediments. Contractional folds are predominantly observed within the Alasehir formation. A north vergent, plunging, asymmetrical to overturned geometry characterizes these folds and they are commonly observed in association with south dipping both thrust and reverse faults; the presence of thrust/reverse faults in the Gediz Graben is documented for the first time here. Fault data suggest an approximately N–S direction of compression that has governed the contractional deformation. Yet the limited distribution of these structures prevents to relate them with confidence to a regional deformation phase. Extensional folds occur in association with normal faults either as structures longitudinal or transverse with respect to the general graben trend. Transverse folds are a very common within the buried graben block, owing to the lateral displacement gradients (lateral difference in offset) on the individual fault segments along the southern margin of the graben. Synclines and anticlines have formed at displacement maxima and minima, respectively. Thickness of strata increases at synclines and decreases at anticlines, thus indicating the syn-depositional origin of the folding. 相似文献
6.
五种不同边界几何条件的平面砂箱实验模型表明,一个方向的伸展变形可因伸展边界方向的变化形成不同走向的正断层,伸展裂陷盆地中不同走向的正断层并非一定代表不同方向区域构造应力作用、或多期构造变形的结果。伸展裂陷盆地正断层走向受伸展边界走向和构造伸展的方向共同控制,伸展边界的控制力随距离增大而逐渐衰减。伸展边界附近的断层走向主要受伸展边界方向控制,大致反映伸展边界方向。盆地内部断层走向主要受构造伸展方向控制(趋向于垂直构造伸展方向),主要反映构造伸展方向。盆地伸展边界方向的变化可以引起伸展裂陷盆地内部断层走向的转向。因铲式正断层上盘滚动变形产生的正断层,其走向平行于铲式边界断层的走向。 相似文献
7.
Superposed to ductile syn-metamorphic deformations, post-foliation deformations affect metamorphic units during their exhumation. Understanding the role of such deformations in the structuration of metamorphic units is key for understanding the tectonic evolution of convergence zones. We characterize post-foliations deformations using 3D modelling which is a first-order tool to describe complex geological structures, but a challenging task where based only on surface data. We propose a modelling procedure that combines fast draft models (interpolation of orientation data), with more complex ones where the structural context is better understood (implicit modelling), allowing us to build a 3D geometrical model of Syros Island blueschists (Cyclades), based on field data. With our approach, the 3D model is able to capture the complex present-day geometry of the island, mainly controlled by the superposition of three types of post-metamorphic deformations affecting the original metamorphic pile: i) a top-to-South ramp-flat extensional system that dominates the overall island structure, ii) large-scale folding of the metamorphic units associated with ramp-flat extensional system, and iii) steeply-dipping normal faults trending dominantly NNW-SSE and EW. The 3D surfaces produced by this method match outcrop data, are geologically consistent, and provide reasonable estimates of geological structures in poorly constrained areas. 相似文献
8.
《Journal of Asian Earth Sciences》2001,19(1-2):1-15
An association of westerly verging asymmetric folds, easterly dipping cleavages and contractional faults control the pattern and intensity of structures at different scales in the southern Nallamalai fold–fault belt, Cuddapah district of Andhra Pradesh, Southern India. Variation in structural geometry is manifested across the section by the occurrence of relatively low amplitude folds, sometimes only a monocline and by the near absence of contractional faults in the WSW, but tight to isoclinal folds with frequent fold–fault interactions through the central areas towards ENE.The relationships of structural elements in terms of orientation, style, sense of movement and general vergence indicate their development under a progressive contractional deformation. The structures are interpreted to result from a combination of bulk inhomogeneous shortening across the belt and a top-to-west, variable simple shear. Localized developments of crenulation cleavage, rotation of cleavage in the shorter limbs of some mesoscale asymmetric folds and general variation of structural elements in morphology and associations across the belt, indicate partitioning of deformation and a varying degree of non-coaxiality in discrete domains of the bulk deformation. 相似文献
9.
Amara Masrouhi Olivier Bellier Hemin Koyi 《International Journal of Earth Sciences》2014,103(3):881-900
Detailed geologic mapping, structural analysis, field cross-sections, new dating based on planktonic foraminifera, in addition to gravity signature of Lorbeus diapir, are used to characterize polyphase salt diapirism. This study highlights the role of inherited faulting, which controls and influences the piercement efficiency and the style and geometry of the diapir; and also the localization of evaporite early ascent displaying diapiric growth during extension. Salt was extruded along the graben axis developed within extensional regional early Cretaceous tectonic associated with the North African passive margin evolution. Geologic data highlight reactive diapirism during Albian time (most extreme extension period) and passive diapirism during the late Cretaceous post-rift stage. Northeastern Maghreb salt province gives evidences that contractional deformations are not associated with significant diapirism. During shortening, the initial major graben deforms as complex anticlines where diapirs are squeezed and pinched from their feeding. 相似文献
10.
《Journal of Structural Geology》1999,21(8-9):1011-1018
In fold-and-thrust belts that experienced both pre-orogenic and post-orogenic extension, it may be difficult to establish whether observed normal faults pre-dated, post-dated, or were synchronous with thrusting. Geometrical structural patterns may be insufficient to constrain the relative chronology of extensional and contractional deformations. The systematic use of kinematic criteria makes it possible to unequivocally define the timing relationships of reverse and normal fault development, and hence to correctly unravel complex structural evolutions. Kinematic analysis in the southernmost Umbria–Marche Apennines of Italy, where both normal and thrust faults are present, revealed a history of repeated tectonic inversion, characterised by two distinct stages of extension separated by an episode of folding and thrusting. Structural overprinting relationships observed at thrust–normal fault intersections were useful for: (i) removing sequentially younger deformations; and hence (ii) separating and quantifying the effects of orogenic contraction from those of both pre-orogenic and post-orogenic extension. 相似文献
11.
Seung-Ik Park Jungrae Noh Hee Jun Cheong Sanghoon Kwon Yungoo Song Sung Won Kim M.Santosh 《地学前缘(英文版)》2019,10(3):909-925
During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where the Early-Middle Jurassic intra-arc volcano-sedimentary Oseosan Volcanic Complex was developed on top of the Late Triassic-Early Jurassic post-collisional sequences, namely the Chungnam Basin. The basin shortening was accommodated mostly by contractional faults and related folds. In the basement, regional high-angle reverse faults as well as low-angle thrusts accommodate the overall shortening, and are compatible with those preserved in the cover. This suggests that their spatial and temporal development is strongly dependent on the initial basin geometry and inherited structures.Changes in transport direction observed along the basement-sedimentary cover interface is a characteristic structural feature, reflecting sequential kinematic evolution during basin inversion. Propagation of basement faults also enhanced shortening of the overlying sedimentary cover sequences. We constrain timing of the Late Jurassic-Early Cretaceous(ca. 158-110 Ma) inversion from altered K-feldspar 40 Ar/39 Ar ages in stacked thrust sheets and K-Ar illite ages of fault gouges, along with previously reported geochronological data from the area. This "non-magmatic phase" of the Daebo Orogeny is contemporaneous with the timing of magmatic quiescence across the Korean Peninsula. We propose the role of flat/low-angle subduction of the Paleo-Pacific Plate for the development of the "Laramide-style" basement-involved orogenic event along East Asian continental margin. 相似文献
12.
J. -L. Mansy G. M. Manby O. Averbuch M. Everaerts F. Bergerat B. Van Vliet-Lanoe J. Lamarche S. Vandycke 《Tectonophysics》2003,373(1-4):161
The geometry and dynamics of the Mesozoic basins of the Weald–Boulonnais area have been controlled by the distribution of preexisting Variscan structures. The emergent Variscan frontal thrust faults are predominantly E–W oriented in southern England while in northern France they have a largely NW–SE orientation.Extension related to Tethyan and Atlantic opening has reactivated these faults and generated new faults that, together, have conditioned the resultant Mesozoic basin geometries. Jurassic to Cretaceous N–S extension gave the Weald–Boulonnais basin an asymmetric geometry with the greatest subsidence located along its NW margin. Late Cretaceous–Palaeogene N–S oriented Alpine (s.l.) compression inverted the basin and produced an E–W symmetrical anticline associated with many subsidiary anticlines or monoclines and reverse faults. In the Boulonnais extensional and contractional faults that controlled sedimentation and inversion of the Mesozoic basin are examined in the light of new field and reprocessed gravity data to establish possible controls exerted by preexisting Variscan structures. 相似文献
13.
河南东濮凹陷构造样式分析 总被引：5，自引：1，他引：4
东濮凹陷古近系整体构造特征表现为复杂半地堑结构,具有"东西分带和南北分段"的特征。NNE向基底断裂发育,呈带状分布。大致沿白庙—南何家一带、毛岗—柳屯一带发育两条EW向的区域性构造变换带,将古近系伸展断陷分为南、中、北3个区段,不同区段横剖面上的构造样式、沉积格局、乃至油气聚集特征均有很大的差异。在复杂的构造发展过程中,东濮凹陷参与构造变形的岩石类型既有碎屑岩又有盐岩,构造应力场性质以张性为主,后期叠加了扭性应力。因此,在东濮凹陷不同构造部位形成了以伸展断裂构造、变换构造、伸展褶皱和盐构造为主的伸展构造样式,伴有走滑构造样式,盆地性质为裂谷盆地。 相似文献
14.
鄂尔多斯盆地周边断裂运动学分析与晚中生代构造应力体制转换 总被引：41，自引：3，他引：41
基于对鄂尔多斯盆地西南缘构造带、中央断裂、东缘边界带和东北部地区的断裂几何特征、运动学及其活动期次的野外观察和测量,并根据断层面上滑动矢量的叠加关系和区域构造演化历史,确定了鄂尔多斯盆地周边地带晚中生代构造主应力方向、应力体制及其转换序列,提出了4阶段构造演化模式和引张-挤压交替转换过程。早中侏罗世,盆地处于引张应力环境,引张方向为N-S至NNE-SSW向。中侏罗世晚期至晚侏罗世,构造应力场转换为挤压体制,盆地周缘遭受近W-E、NW-SE、NE-SW等多向挤压应力作用。早白垩世,盆地构造应力场转换为引张应力体制,引张应力方向为近W-E、NW-SE和NE-SW向。早白垩世晚期至晚白垩世,盆地应力体制再次发生转换,从前期的引张应力体制转换为NW-SE向挤压应力体制。晚中生代构造应力体制转换和应力场方向变化不仅记录了不同板块之间汇聚产生的远程效应,同时记录了盆地深部构造-热活动事件,并对盆地原型进行了一定的改造。 相似文献
15.
《International Geology Review》2012,54(15):1889-1921
This article describes the geometry and structural architecture of the Viù Deformation Zone (VDZ), a brittle-ductile to brittle structure affecting the metamorphic units of the inner Western Alps, and its role in modifying the pre-existing syn-metamorphic structural setting. The VDZ reactivates and displaces the contact between two different oceanic units, the Lanzo Ultramafic Complex and the Lower Susa–Lanzo Valleys Unit, characterized by polyphase syn-metamorphic deformation. It shows a strike-slip duplex geometry, constituted by N–S reverse-dextral faults linked by NW–SE antithetical sinistral-reverse faults, and represents a contractional step-over zone along a N–S regional dextral-reverse structure, the Col del Lis-Trana Deformation Zone. Formation of these transpressional structures steepened the Lanzo Ultramafic Complex during the last stages of its exhumation. The 3D geometry of the VDZ was strongly controlled by the reactivation of pre-existing structures, such as the buried western edge of the Ivrea body and metamorphic foliations. Brittle reactivation also induced block rotation along the VDZ, causing anomalous kinematic relations between the VDZ-associated faults. This study, hence, shows that in metamorphic orogens the mechanisms generating strike-slip duplexes may be different from those classically provided by the literature, with brittle reactivation and block rotation strongly prevailing on newly formed faults. In such orogens, moreover, rotations induced by transpressional faulting may sometimes be mistaken for steep syn-metamorphic shear zones. Underestimating the effects of later brittle deformation and associated rotations may cause erroneous interpretations of the tectonic evolution of orogens. 相似文献
16.
通过精细的地震资料解释,在塔里木盆地中部的满西地区发现晚志留世-石炭纪伸展构造。伸展构造由一系列规模不大的正断层组成,平面上组成两条北东-南西向的左行雁列状正断层带,剖面上构成负花状构造和堑垒构造。根据生长系数计算结果,正断层形成于晚志留世,在泥盆纪和石炭纪持续活动,于石炭纪末停止活动。正断层活动的高峰期为晚志留世。该期伸展构造在塔中和塔北地区也有发育,反映当时塔里木盆地处于区域性伸展构造背景。塔里木盆地晚志留世-石炭纪的伸展构造,是昆仑早古生代晚期（晚奥陶世-中志留世）碰撞造山后构造应力松弛作用的产物。 相似文献
17.
Oblique rifting in Salina, Lipari and Vulcano islands (Aeolian islands, southern Italy) 总被引：1，自引：0，他引：1
A structural analysis carried out on the volcanic products of the islands of Salina, Lipari and Vulcano (Aeolian archipelago) points out that the large-scale tectonic setting is dominated by NW-SE trending right-lateral extensional strike-slip faults and by N-S to NE-SW trending normal faults and fractures. This fault pattern generates pull-apart type structures, developing between different right-hand overlapping fault segments and a characteristic extensional imbricate fan geometry at the tip of the major strike-slip faults. All the structures, representing the surface expression of an active crustal discontinuity which controls the evolutionary history of the magmatism of the three islands, are kinematically compatible with a N100°E extension related to a rifting process affecting southern Italy. 相似文献
18.
近几年来对湖南省页岩气地质条件进行了大量调查研究,但对页岩气的构造保存条件研究和评价很少,因而影响了区域页岩气勘查工作的科学部署。笔者在湘中南永州凹陷西北缘的水岭-大庙口地区开展了1∶50 000页岩气地质调查,对该地区构造特征和构造演化过程进行了研究,在此基础上探讨了页岩气保存和富集的构造条件。调查区构造变形强烈,主要构造类型有：上古生界盖层中发育的NNW-近SN向（主）褶皱和EW向（次）褶皱,下古生界中发育的NNE向和NE向膝折,切割上古生界和下古生界的NNW-SN向、NE向、NW向等3组断裂（主要为逆断裂、正断裂,少量为走滑断裂）,下古生界中极为发育的NNW向板劈理以及泥盆系跳马涧组中发育的SN向、NNE向破劈理等。结合区域构造背景,初步确定上述构造主要形成于早古生代以来的8期构造变形事件,其中以加里东运动、印支运动和早燕山运动的挤压事件以及白垩纪区域伸展事件等最为重要。奥陶系烟溪组和天马山组底部的黑色页岩为调查区页岩气勘探目标层,但钻孔岩心页岩气解吸实验表明含气性极差。分析认为,多期构造运动造成的抬升和剥蚀及形成的断裂、劈理,既导致页岩气的散逸,也使得目标层仅局部有保存;多期构造运动形成的复杂构造样式,使得上古生界之下目标层的空间展布特征难以探明;加里东运动和印支运动所诱发花岗质岩浆活动相关的高地热场区会显著增高有机质热演化程度,总体不利于页岩气的保存。调查区对页岩气富集和保存不利的构造条件基本适用于永州凹陷及周缘其它地区,因此认为永州凹陷及周缘页岩气成藏潜力非常有限。本研究成果对区域页岩气成藏条件的客观认识以及页岩气勘查工作的合理部署具有重要的启示意义。 相似文献
19.
《Geodinamica Acta》2013,26(6):375-387
Information from surface and subsurface geology (boreholes and seismic reflection lines) are used to depict the geometry of the extensional structures (low-angle normal faults and related Tuscan Nappe megaboudins) affecting the Mt. Amiata geothermal area and developed during the early stage of the extensional tectonics which affected the inner Northern Apennines and Tyrrhenian Sea from the Early-Middle Miocene. Normal faulting involved the thickened middle-upper crust after the collisional stage and, in the Mt. Amiata region, took place over relatively short periods (5-7 Ma) characterised by rapid extensional strain rates. Normal faults showing articulated geometry (flat-ramp-flat) characterised by subhorizontal detachments (flats) and synthetic ramps, caused widespread megaboudinage mainly in the sedimentary tectonic units and particularly in the Tuscan Nappe. Evaporites occurring at the base of the Tuscan Nappe, the deepest sedimentary tectonic unit of the Northern Apennines, controlled the geometry of the faults, and rift-raft tectonics may be the style of this first extensional phase. Three Tuscan Nappe extensional horses (megaboudins) have been recognised in the subsurface of the Mt. Amiata area. They are characterised, in map view, by elliptical shapes and show a mean NNW-SSE lengthening. They are delimited at the base and at the top by east-dipping flats, while their western and eastern margins coincide with east-dipping ramps. On the whole, considering their geometrical features, these megaboudins correspond to extensional horses belonging to an asymmetrical east-dipping extensional duplex system. Rollover anticlines deformed the western ramp of the megaboudins and rotated the uppermost flat as well as all the structures previously developed, which became steeply-dipping to the west. 相似文献