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1.
The Pyramid Lake fault zone is within the Honey Lake—Walker Lake segment of the Walker Lane, a NW-trending zone of right-slip transcurrent faulting, which extends for more than 600 km from Las Vegas, Nevada, to beyond Honey Lake, California. Multiscale, multiformat analysis of Landsat imagery and large-scale (1: 12,000) lowsun angle aerial photography, delineated both regional and site-specific evidence for faults in Late Cenozoic sedimentary deposits southwest of Pyramid Lake. The fault zone is coincident with a portion of a distinct NW-trending topographic discontinuity on the Landsat mosaic of Nevada. The zone exhibits numerous geomorphic features characteristic of strike-slip fault zones, including: recent scarps, offset stream channels, linear gullies, elongate troughs and depressions, sag ponds, vegetation alignments, transcurrent buckles, and rhombohedral and wedge-shaped enclosed depressions. These features are conspicuously developed in Late Pleistocene and Holocene sedimentary deposits and landforms.The Pyramid Lake shear zone has a maximum observable width of 5 km, defined by Riedel and conjugate Riedel shears with maximum observable lenghts of 10 and 3 km, respectively. P-shears have formed symmetrical to the Riedel shears and the principal displacement shears, or continuous horizontal shears, isolate elongate lenses of essentially passive material; most of the shears are inclined at an angle of approximately 4° to the principal direction of displacement. This suggests that the shear zone is in an early “PreResidual Structure” stage of evolution, with the principal deformation mechanism of direct shear replacing the kinematic restraints inherent in the strain field.Historic seismic activity includes microseismic events and may include the earthquake of about 1850 reported for the Pyramid Lake area with an estimated Richter magnitude of 7.0. Based on worldwide relations of earthquake magnitude to length of the zone of surface rupture, the Pyramid Lake fault zone is inferred to be capable of generating a 7.0–7.5-magnitude event for a maximum observable length of approximately 6 km and a 6.75–7.25-magnitude event for a half length of approximately 30 km. 相似文献
2.
The Olinghouse fault zone is one of several NE—ENE-trending fault zones and lineaments, including the Midas Trench and the Carson—Carson Sink Lineament, which exhibit left-lateral transcurrent movement conjugate to the Walker Lane in western Nevada. The active portion of this fault zone extends for approximately 23 km, from 16 km east of Reno, Nevada, to the southern extent of Pyramid Lake. The fault can be traced for most of its length from its geomorphic expression in the hilly terrain, and it is hidden only where overlain by recent alluvial sediments. Numerous features characteristic of strike-slip faulting can be observed along the fault, including: scarps, vegetation lines, sidehill and shutter ridges, sag ponds, offset stream channels and stone stripes, enclosed rhombohedral and wedge-shaped depressions, and en-echelon fractures.A shear zone having a maximum observable width of 1.3 km is defined principally by Riedel shears and their symmetrical P-shears, with secondary definition by deformed conjugate Riedel shears. Several continuous horizontal shears, or principal displacement shears, occupy the axial portion of the shear zone. The existence of P-shears and principal displacement shears suggests evolution of movement along the fault zone analogous to the “Post-Peak” or “Pre-Residual Structure” stage.Historic activity (1869) has established the seismic potential of this zone. Maximum intensities and plots of the isoseismals indicate the 1869 Olinghouse earthquake had a magnitude of 6.7. Field study indicates the active length of the fault zone is at least 23 km and the maximum 1869 displacement was 3.65 m of left-slip. From maximum fault length and maximum fault displacement to earthquake magnitude relations, this corresponds to an earthquake of about magnitude 7. 相似文献
3.
用物理模拟实验研究走滑断裂和拉分盆地 总被引：6，自引：1，他引：5
本文按照下地壳和岩石圈地幔塑性流动控制上地壳构造变形的思想,采用脆延性双层模型,在考虑模型相似性的条件下,通过延性层流动驱动脆性层进行走滑断裂和拉分盆地模拟实验。实验结果表明,在左行走滑阶段发育两条"S"型左行右阶断裂带;在右行走滑改造阶段,早期左行右阶断裂带被改造为"Z"型右行右阶断裂带。走滑断裂发育过程中共有三种类型的拉张伸展:(1)"S"型破裂逐渐伸展,形成多个菱形盆地;(2)几个相邻的斜列"S"型断裂在剪切作用下端部被错断连通,形成"地堑-地垒"构造;(3)在右行走滑阶段,沿右行右阶断裂拉张形成拉分盆地。先存的上隆拱张断裂限制了走滑断裂的位置和方向。脆性层强度对走滑断裂的形成和发展具有约束作用,脆性层结构对脆延性的层间耦合作用和走滑断裂特征具有显著影响。 相似文献
4.
5.
J. Neugebauer M. Löffler H. Berckhemer A. Yatman 《International Journal of Earth Sciences》1997,86(1):93-102
The course of the active North Anatolian Fault system from Lake Abant to Lake Sapanca was traced by its high micro-earthquake activity. If approaching from the east this section includes a broad south to north overstep (fault offset) of the main fault. Local seismicity has been recorded in this area by a semi-permanent network of 8 stations since 1985 within the frame of the Turkish–German Joint Project for Earthquake Research. The effect of the overstep and its complex fracture kinematics are reflected by the seismicity distribution, the variations of composite fault-plane solutions, and by the spatial coda-Q distribution. Areas of different stress orientation can be distinguished and assigned to different groups of faults. The stresses and the tectonic pattern only in part correspond to a simple model of an extensional overstep and its correlative pull-apart basin. Other types of deformation involved are characterized by normal faulting on faults parallel to the general course of the main strike-slip fault and by synthetic strike-slip faults oriented similar to Riedel shears. Shear deformation by this fault group widely distributed in an area north and east of the main fault line may play an important role in the evolution of the overstep. The development of a pull-apart basin is inhibited along the eastern half of the overstep and compatibility of both strands of the main fault (Bolu–Lake Abant and Lake Sapanca– Izmit–Marmara Sea) seems to be achieved with the aid of the fault systems mentioned. The extension of the missing part of the pull-apart basin seems to be displaced to positions remote from the Lake Abant–Lake Sapanca main fault line, i.e. to the Akyaz?–Düzce basin tract. Highest Q-values (lowest attenuation of seismic waves) were found in the zone of highest seismicity north and west of the overstep which is the zone of strongest horizontal tension. If high coda-Q is an indicator for strong scattering of seismic waves it might be related to extensional opening of fractures. 相似文献
6.
要通过在TM遥感图像解译和野外观测的基础上,描述了东昆仑断裂带东段活动形迹的组成和活动断层地貌特征,阐述了甘南高原西秦岭地区新近纪拉分盆地的沉积-构造特征,提出了该区东昆仑-秦岭断裂系晚新生代左旋走滑伸展-走滑挤压-走滑伸展的3个阶段的构造变形模式。指出,中新世晚期至上新世早期,东昆仑-秦岭断裂系以左旋走滑伸展活动为主,伴随着西秦岭地区拉分盆地的形成和超基性火山岩群的发育。这期左旋走滑伸展活动向东扩展导致了渭河盆地新近纪引张应力方向由早期的NE-SW向转变为晚期的NW—SE向。上新世晚期以来(约3．4Ma以前),东昆仑-秦岭断裂系以左旋走滑挤压活动为主,导致早期拉分盆地的轻微褶皱变形,走滑挤压活动主要集中在东昆仑东段玛沁-玛曲主断裂带上。该期构造变动持续到早更新世,它的向东扩展产生了广泛的地壳形变效应,包括青藏东缘岷山隆起带的快速崛起、华北地区汾-渭地堑系的形成和发展以及郯庐断裂带右旋走滑活动等。中、晚更新世时期,断裂系以走滑伸展变形为主,主要集中在东昆仑断裂带东段3个分支上,地块向东挤出伴随着顺时针旋转。 相似文献
7.
This paper presents the results of a detailed structural analysis of the northern Nijar and southern Vera basins with special emphasis on the evolution of the regional stress field and the associated timing of movement of the Serrata, Gafarillos and Palomares strike-slip fault zones. These major fault zones control the Neogene deformation of the SE Internal Betic Cordilleras in Spain. Detailed stress analysis on Neogene sediments of the Vera and Nijar basins shows a strike-slip regime with NW–SE-oriented subhorizontal maximum principal stress (σ1) during Tortonian and earliest Messinian times. Under the influence of this stress field, dextral displacement along the N090E-trending Gafarillos fault zone resulted in deformation of the sediments of the southern Sorbas and northeastern Nijar basins. During the early Messinian a clock-wise rotation of the stress field occurred. Stress analysis in rocks with late–early Messinian up to Quaternary ages in the Nijar and Vera basins indicates a strike-slip regime with N–S-oriented subhorizontal maximum principal stress (σ1). Under the influence of this stress field the main activity along the N010E-striking Palomares strike-slip fault zone took place, resulting in deformation of the Neogene sediments of the southeastern Vera basin and culminating in a maximum sinistral displacement of more than 20 km. At the same time the stress field was not suitably oriented to exert a large shear component on the Gafarillos fault zone, which activity ended after the earliest Messinian. Fault and outcrop patterns of syntectonic Neogene sediments in the Vera basin show that displacement along the Palomares fault zone decreased at the end of the Middle Miocene although minor displacement phases may still have occurred during the Late Miocene and possibly even Pliocene. From the Middle Miocene onward, deformation in the Nijar basin was controlled by sinistral displacement along the N040E-trending Serrata strike-slip fault zone. 相似文献
8.
Cretaceous deformation history of the middle Tan-Lu fault zone in Shandong Province, eastern China 总被引：13，自引：0，他引：13
Based on field analysis of fault-slip data from different rock units of the Cretaceous basins along the middle part of the Tan-Lu fault zone (Shandong Province, eastern China), we document polyphase tectonic stress fields and address the changes in sense of motion of the Tan-Lu fault zone during the Cretaceous. The Cretaceous deformation history of the Tan-Lu fault zone can be divided into four main stages. The first stage, during the earliest Cretaceous, was dominated by N-S extension responsible for the formation of the Jiaolai basin. We interpret this extension to be related to dextral strike-slip pull-apart opening guided by the Tan-Lu fault zone. The second stage, during the middle Early Cretaceous, was overwhelmingly rift-dominated and characterized by widespread silicic to intermediate volcanism, normal faulting and basin subsidence. It was at this stage that the Tan-Lu-parallel Yi-Shu Rift was initiated by E-W to WNW-ESE extension. The tectonic regime then changed during the late Early Cretaceous to NW-SE-oriented transpression, causing inversion of the Early Cretaceous rift basin and sinistral slip along the Tan-Lu fault zone. During the Late Cretaceous, dextral activation of the Tan-Lu fault zone resulted in pull-apart opening of the Zhucheng basin, which was subsequently deformed by NE-SW compression. This deformation chronology of the Tan-Lu fault zone and the associated Cretaceous basins allow us to constrain the regional kinematic models as related to subduction along the eastern margin of Asia, or related to collision in the Tibet region. 相似文献
9.
J. Angelier B. Colletta J. Chorowicz L. Ortlieb C. Rangin 《Journal of Structural Geology》1981,3(4):347-357
A detailed field analysis of Neogene and Quaternary faults in Baja California has enabled us to reconstruct the stress pattern and the tectonic evolution of the central and southern parts of the peninsula. The deformation, which is related to the opening of the gulf, affects the whole peninsula, but decreases from east to west. Most observed faults, normal and/or dextral, strike NNW-SSE to WNW-ESE; their mechanisms include both strike-slip and dip-slip, as well as intermediate motions. Compressional events have occurred since Late Neogene times, but were probably of minor quantitative importance because reverse faults are rare and small.The principal fault pattern includes dextral NNW-SSE Riedel shears and N-S tension faults induced by dextral strike-slip along two main NW-SE fault zones bordering the peninsula: the Gulf of California to the east, which is the most important, and the Tosco-Abreojos fault to the west. The resulting pattern of deformation shows that the eastern part has been a complex transform-extensional zone since Late Miocene-Early Pliocene times. 相似文献
10.
扭动走滑构造是最常见的构造样式之一,走滑拉分盆地也是重要的含油气盆地类型。大地构造运动本质是岩石圈在区域应力场作用下的变形过程,然而真正将走滑断裂和走滑拉分盆地的成因以及它们的特征和岩石圈性质联系起来研究的文献却很少。显然,区域应力场是形成构造运动的前提条件,是外因,决定了运动的基本方式,如走滑、拉张或挤压等(构造类型);而岩石圈是构造运动的主体,是内因,其性质决定了形成构造的规模和具体形态(样式)。中国境内发育的大量走滑断裂体系和走滑盆地展示:古老克拉通上发育大面积分布的多条小位移走滑断裂体系,如塔里木盆地古生代走滑断裂体系;被后期热活动破坏了的克拉通发育多条扭动断裂系,例如华北克拉通东部的郯庐断裂系、兰聊—盐山断裂系、太行山东麓断裂系,并和区域拉张应力场耦合形成雁列式断陷群(如渤海湾盆地);相对较弱的古生代基底岩石圈发育大型单一走滑断层,如郯庐断裂东北段,并沿断裂发育一些相互独立的走滑拉分盆地;而在固结较差的中新生代造山带往往形成一条平直的大型走滑断层,例如阿尔金走滑断裂、海原断裂等。本文内因外因相结合,从扭动应力场和岩石圈强度以及流变学特征,建立了不同岩石圈性质下下部韧性层和顶部(上地壳或上地壳上部)刚性层之间的耦合作用机制以及扭动构造形成和演化模式,较好地解释了中国陆内发育的典型走滑断裂和走滑拉分盆地的成因机制。 相似文献
11.
Hisashi Taniyama 《Engineering Geology》2011,(3):194
A distinct element method analysis is carried out to examine the development of shear bands in overburden soil subjected to a strike-slip fault. About 2.3 million spherical particles are used in the analysis and the results are compared with the shears observed at the Nojima earthquake fault during the 1995 Hyogoken Nanbu earthquake. En echelon shears and secondary shears which strike at lower angles to the basement fault – typical in strike-slip faults – are observed in the numerical analysis. Simple shear in the horizontal plane and drag due to the dependence of velocity on depth are confirmed to control the helicoidal shape of Riedel shears. Rotation of the compressional direction toward the fault strike as a result of slip along Riedel shears is also verified. It is found that the compressional direction is more horizontal within the area enclosed by Riedel shears than in outside areas and that these compressional directions produce secondary lower-angle shears that are less helicoidal. It is shown that the formation of column-like structures of particles and their subsequent buckling play significant micromechanical roles in three-dimensionally wrenched shears. The results of the numerical analysis, such as shear intervals and striking angles, show a resemblance to observational results at sites where sediment contains coarse grains and is subjected to strike slip with a small dip component, although they are not exactly the same as those observed at locations with similar overburden thicknesses. 相似文献
12.
The initiation and linkage of surface fractures above a buried strike-slip fault: An experimental approach 总被引：1，自引：0，他引：1
Surface fractures in the overburdened sedimentary rocks, formed above a deep-seated basement fault, often provide important
information about the kinematics of the underlying master fault. It has already been established that these surface fractures
dynamically evolve and link one another with progressive displacement on the master fault below. In the present study, two
different series of riedel-type experiments were carried out with clay analogue models under different boundary conditions
viz., (i) heterogeneous simple shear of the cover rocks above a buried strike slip fault (wrench system) and (ii) heterogeneous
simple shear with a component of shear-normal compression of the overburden package above a basement fault (transpressional
system), to observe the initiation and linkage of surface fractures with varying T′ (where T′ = thickness of the overburden normalized with respect to the width of the master fault). In the wrench system, Riedel (R)
shears were linked by principal displacement (Y) shears at early stages (shear strain of 0.8 to 1) in thin (2 < T′ < 18) models and finally (at a minimum shear strain of 1.4) gave rise to a through-going fault parallel to the basement fault
without development of any other fracture. Conjugate Riedel (R′) shears develop only within the thicker (T′ > 18) clay models at a minimum shear strain of 0.7. With increasing deformation (at a minimum shear strain of 1.2) two R′
shears were joined by an R shear and finally opened up to make a sigmoidal vein with an asymmetry antithetic to the major
fault-movement sense. Under transpression, the results were similar to that of heterogeneous simple shear for layers 2 < T′ < 15. In layers of intermediate thickness (15 < T′ < 25) early formed high angle R shears were cross cut by low angle R shears (at a minimum shear strain of 0.5 and shortening
of 0.028) and “Riedel-within-Riedel” shears were formed within thick (T′ > 25) models (at minimum shear strain of 0.7 and shortening of 0.1), with marked angularity of secondary fault zone with
the master fault at depth. 相似文献
13.
Joachim Neugebauer 《地学学报》1994,6(4):359-365
Fault blocks passing bends or stepovers in a fault zone must adapt their margins to the uneven fault trace. Two cases of adaption are distinguished for extensional bends or stepovers (transtension): (1) The fault margins close up behind a single bend ('knickpoint') of a strike-slip fault and a 'closing-up structure' (new term) arises or (2) fault-block margins are extended behind a releasing bend (double bend) or stepover parallel to the displacement and a pull-apart basin originates. The dosing up described here is accomplished by acute-angled synthetic strike-slip faults that dissect the straight fault in front of a knickpoint to form a zig-zag block boundary behind it. Crustal extension is also involved in the closing-up structure, but in a different way from typical pull-apart basins.
The closing-up structure illustrated was developed behind an extensional knickpoint in the North Anatolian Fault west of Lake Abant, NW Turkey, where the process of closing up continues to this day. The kinematic model of this closing-up structure is supported by displacements and ruptures observed during the 1967 Mudurnu valley earthquake and the 1957 Abant earthquake. 相似文献
The closing-up structure illustrated was developed behind an extensional knickpoint in the North Anatolian Fault west of Lake Abant, NW Turkey, where the process of closing up continues to this day. The kinematic model of this closing-up structure is supported by displacements and ruptures observed during the 1967 Mudurnu valley earthquake and the 1957 Abant earthquake. 相似文献
14.
Understanding the roles of Cenozoic strike-slip faults in SE Asia observed in outcrop onshore, with their offshore continuation has produced a variety of structural models (particularly pull-apart vs. oblique extension, escape tectonics vs. slab-pull-driven extension) to explain their relationships to sedimentary basins. Key problems with interpreting the offshore significance of major strike-slip faults are: (1) reconciling conflicting palaeomagnetic data, (2) discriminating extensional, and oblique-extensional fault geometries from strike-slip geometries on 2D seismic reflection data, and (3) estimating strike-slip displacements from seismic reflection data.Focus on basic strike-slip fault geometries such as restraining vs. releasing bends, and strongly splaying geometries approach the gulfs of Thailand and Tonkin, suggest major strike-slip faults probably do not extend far offshore Splays covering areas 10,000’s km2 in extent are characteristic of the southern portions of the Sagaing, Mae Ping, Three Pagodas and Ailao Shan-Red River faults, and are indicative of major faults dying out. The areas of the fault tips associated with faults of potentially 100 km+ displacement, scale appropriately with global examples of strike-slip faults on log–log displacement vs. tip area plots. The fault geometries in the Song Hong-Yinggehai Basin are inappropriate for a sinistral pull-apart geometry, and instead the southern fault strands of the Ailao Shan-Red River fault are interpreted to die out within the NW part of the Song Hong-Yinggehai Basin. Hence the fault zone does not transfer displacement onto the South China Seas spreading centre. The strike-slip faults are replaced by more extensional, oblique-extensional fault systems offshore to the south. The Sagaing Fault is also superimposed on an older Paleogene–Early Miocene oblique-extensional rift system. The Sagaing Fault geometry is complex, and one branch of the offshore fault zone transfers displacement onto the Pliocene-Recent Andaman spreading centre, and links with the West Andaman and related faults to form a very large pull-apart basin. 相似文献
15.
The Gondwana basins of peninsular India are traditionally considered as extensional-rift basins due to the overwhelming evidence
of fault-controlled synsedimentary subsidence. These basins indeed originated under a bulk extensional tectonic regime, due
to failure of the attenuated crust along pre-existing zones of weakness inherited from Precambrian structural fabrics. However,
disposition of the basins and their structural architecture indicate that the kinematics of all the basins cannot be extensional.
To maintain kinematic compatibility with other basins as well as the bulk lateral extension, some basins ought to be of strike-slip
origin. The disposition, shape and structural architecture of the Satpura basin, central India suggest that the basin could
be a pull-apart basin that developed above a releasing jog of a left-stepping strike-slip fault system defined by the Son-Narmada
south fault and Tapti north fault in consequence to sinistral displacement along WSW-ENE. Development of a sedimentary basin
under the above-mentioned kinematic condition was simulated in model experiments with sandpack. The shape, relative size,
stratigraphic and structural architecture of the experimental basin tally with that of the Satpura basin. The experimental
results also provide insights into the tectono-sedimentary evolution of the Satpura basin in particular and pull-apart basins
in general. 相似文献
16.
《International Geology Review》2012,54(8):701-713
Compressional or extensional troughs occupied by at least two sedimentary fills of dissimilar age, origin, facies, internal structure, and deformation pattern are herein termed superimposed basins. The lower and older fill of such basins is inherited from the latest compressional paleotectonic regime, and therefore is highly deformed (folded to thrust faulted). In contrast, the upper fill (neotectonic fill) is nearly flat, or undeformed, resting on the erosional surface of the lower fill with an angular unconformity. Superimposed basins occur mostly in or adjacent to recently active extensional terrains and recent strike-slip fault zones cutting across suture zones. Within the framework of neotectonics, recent geologic studies such as field geologic mapping, measured stratigraphic sections, aerial photography, and remote-sensing studies conducted in Turkey have shown that a number of well-developed and preserved superimposed basins occur along and adjacent to the North Anatolian transform fault (NATF), obliquely crossing the late Tertiary Izmir-Ankara-Erzincan suture zone (IAESZ). One such superimposed basin is the Refahiye, previously and erroneously interpreted to be a strike-slip basin of Pliocene age. In contrast, this study demonstrates that it is a well-preserved superimposed basin consisting of a combination of both an early-formed, early-middle Miocene piggy-back basin (the older Refahiye basin) and a newly developing strike-slip basin (the Kova basin). The Refahiye basin, located on the southern block of the Niksar-Erzincan segment of the Northern Anatolian fault master strand (NAFMS), contains two fills: (1) lower-middle Miocene latest paleotectonic fill (lower fill), and (2) Plio-Quaternary neotectonic fill (upper fill). The lower fill consists mostly of fluvial red clastics approximately 1 km thick with intercalations of gypsum lenses and shallow-marine reefal limestone of early-middle Miocene age. It is intensely folded, thrust-faulted, and not confined the present-day configuration of the Refahiye basin. The lower fill and its deformational structures, such as folds and thrust faults, are crossed and displaced dextrally by an active strike-slip fault system, the NATE In contrast, the upper fill, which rests on the erosional surface of the lower fill with an angular unconformity, consists of Plio-Quaternary terrace conglomerates, Quaternary imbricated gravels, and fine-grained Quaternary plain sediments (mostly silt and clay); these were deposited within a newly developing strike-slip basin—the Kova pull-apart basin—superimposed on the lower fill of the Refahiye basin. The upper fill is undeformed and nearly flat-lying. All these characteristics reveal that the present configuration of the Refahiye basin is a superimposed basin, herein termed the Refahiye superimposed basin. 相似文献
17.
玉树断裂带左旋走滑活动标志及其几何学
与运动学特征 总被引：2，自引：1，他引：1
玉树断裂带位于甘孜-玉树断裂带北西段,是一条总体呈NWW向展布的左旋走滑活动断裂带.沿断裂带发育错断水系与冲沟、拉分盆地、地震地表破裂与断裂破碎带等一系列反映玉树断裂带左旋走滑活动的典型地质-地貌标志.在室内遥感解译的基础上,结合最新的野外实地调查成果,对沿玉树断裂带上反映其左旋走滑活动的地质-地貌标志进行了总结,并对断裂带的几何学与运动学特征进行了综合分析.结果表明,玉树断裂带总长约150km,总体走向120～130°,自西向东可划分为呈左阶雁列分布的陇蒙达-结隆段、结隆-结古段和结古-查那扣段3段.沿该断裂带发育的串珠状拉分断陷盆地规模的大小反映出玉树断裂带自西向东拉张效应逐渐减弱、挤压效应逐渐增强的特点.玉树2010年7.1级地震的宏观震中处于晚第四纪活动性最为显著的中段,而仪器震中恰好处于该断裂带的不连续部位,进一步证明雁列走滑活动断裂带上的不连续部位通常是强震活动的初始破裂区域. 相似文献
18.
辽东湾北部地区走滑构造特征与油气富集规律 总被引：4，自引：2，他引：2
辽东湾北部地区右行走滑构造特征较为典型,主要表现为:沿走滑断裂带发育雁行式伸展断裂;剖面上发育花状构造;走滑断裂沿走向呈“S”型或反“S”型波状弯曲;沿走滑断裂带断槽与断鼻构造相间分布。分析认为,渐新世晚期,辽东湾北部地区南北向拉张、东西向挤压的区域应力场控制了右行走滑构造的形成,断槽与断鼻构造相间分布是由于沿走滑断裂带局部应力场性质发生改变所致。右行走滑断裂的“S”型弯曲部位为增压弯部位,走滑断裂两侧断块在此汇聚,地层因应力集中而形成断鼻构造;右行走滑断裂的反“S”型弯曲部位为释拉张部位,走滑断裂两侧断块在此离散,地层因拉张而发生断陷形成断槽。受走滑构造所控制,油气沿走滑断层自断槽向断鼻方向运移、聚集而成藏。研究走滑构造发育特征,对于预测圈闭分布以和研究油气富集规律具有重要意义。 相似文献
19.
The Tertiary Mineoka ophiolite occurs in a fault zone at the intersection of the Honshu and Izu forearcs in central Japan and displays structural evidence for three major phases of deformation: normal and oblique-slip faults and hydrothermal veins formed during the seafloor spreading evolution of the ophiolite at a ridge-transform fault intersection. These structures may represent repeated changes in differential stress and pore-fluid pressures during their formation. The second series of deformation is characterized by oblique thrust faults with Riedel shears and no significant mineral veining, and is interpreted to have resulted from transpressional dextral faulting during the obduction of the ophiolite through oblique convergence and tectonic accretion. This deformation occurred at the NW corner of a TTT-type (trench–trench–trench) triple junction in the NW Pacific rim before the middle Miocene. The third series of deformation of the ophiolite is marked by contractional and oblique shear zones, Riedel shears, and thrust faults that crosscut and offset earlier structures, and that give the Mineoka fault zone its lenticular (phacoidal) fabric at all scales. This deformation phase was associated with the establishment and the southward migration of the TTT Boso triple junction and with the kinematics of oblique subduction and forearc sliver fault development. The composite Mineoka ophiolite hence displays rocks and structures that evolved during its complex geodynamic history involving seafloor spreading, tectonic accretion, and triple junction evolution in the NW Pacific Rim. 相似文献
20.
The Main Recent Fault of the Zagros Orogen is an active major dextral strike-slip fault along the Zagros collision zone, generated by oblique continent–continent collision of the Arabian plate with Iranian micro-continent. Two different fault styles are observed along the Piranshahr fault segment of the Main Recent Fault in NW Iran. The first style is a SW-dipping oblique reverse fault with dextral strike-slip displacement and the second style consists of cross-cutting NE-dipping, oblique normal fault dipping to the NE with the same dextral strike-slip displacement. A fault propagation anticline is generated SW of the oblique reverse fault. An active pull-apart basin has been produced to the NE of the Piranshahr oblique normal fault and is associated with other sub-parallel NE-dipping normal faults cutting the reverse oblique fault. Another cross-cutting set of NE–SW trending normal faults are also exist in the pull-apart area. We conclude that the NE verging major dextral oblique reverse fault initiated as a SW verging thrust system due to dextral transpression tectonic of the Zagros collision zone and later it has been overprinted by the NE-dipping oblique normal fault producing dextral strike-slip displacement reflecting progressive change of transpression into transtension in the collision zone. The active Piranshahr pull-apart basin has been generated due to a releasing damage zone along the NW segment of the Main Recent Fault in this area at an overlap of Piranshahr oblique normal fault segment of the Main Recent Fault and the Serow fault, the continuation of the Main Recent Fault to the N. 相似文献