共查询到20条相似文献，搜索用时 15 毫秒
1.
南海北部神狐陆坡限制型滑塌体特征及成因机理 总被引：1，自引：0，他引：1
滑塌体是深水沉积的重要组成部分,研究滑塌体沉积有助于揭示深水沉积过程。利用高精度多道地震资料,首次在南海北部神狐陆坡段发现了规模逾千平方千米的限制型滑塌体,它在顺坡滑塌时,未能超越下坡地层的围限,突然终止于下坡未变形地层中,因此陡冲斜坡两侧的地震相特征发生截然的变化。滑塌体整体呈楔形,内部呈杂乱反射,前端存在逆冲断层以及挤压褶皱。由于顺坡滑塌距离较短,因此与非限制型滑塌体相比,限制型滑塌体内部地层连续性较好。结合神狐滑塌体地震反射特征并通过与世界典型滑塌体的对比,可知滑塌体的厚度、地形坡度二者共同控制了神狐滑塌体的发育类型,前端地形突起对其发育没有影响。 相似文献
2.
Late Cenozoic Deformation Sequence of a Thrust System along the Eastern Margin of Pamir, Northwest China 总被引：1，自引：1，他引：0
A thrust belt formed in the basin along the eastern margin of Pamir. The thrust belt is about 50 km wide, extends about 200 km, and includes three compressive structures from south to north: the blind Qipan structural wedge and Qimugen structural wedge, and the exposed Yengisar anticline. The thrust belt displays a right-stepping en echelon pattern. The Qipan structural wedge dies out northward to the west of the Qimugen structural wedge, and the Qimugen structural wedge dies out northward to the west of the Yengisar anticline. Detailed analysis of seismic reflection profiles of the western Tarim Basin reveal that fan-shaped growth strata were deposited in the shallow part of the thrust belt, recording the deformation sequence of the thrust belt. The depth of the Cenozoic growth strata decreases from south to north. The growth strata of the Qipan structural wedge is located in the middle-lower section of the Pliocene Artux Formation (N2a), the growth strata of the Qimugen structural wedge is close to the bottom of the Pleistocene Xiyu Formation (Q1x), and the growth strata of the Yengisar anticline is located in the middle section of the Xiyu Formation (Q1x). Combined with magnetostratigraphic studies in the western Tarim basin, it can be preliminarily inferred that the deformation sequence of the thrust belt along the eastern margin of Pamir is progressively younger northward. The geometry and kinematic evolution of the thrust belt in the eastern margin of Pamir can be compared with previous analogue modeling experiments of transpressional deformation, suggesting that the thrust belt was formed in a transpressional tectonic setting. 相似文献
3.
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
4.
M. Parish 《Journal of Structural Geology》1984,6(3):247-255
The Gavarnie nappe is a feature of the Tertiary Pyrenean orogen and is shown to consist of at least two thrust sheets of Palaeozoic rocks which are overlain by a southward-dipping sequence of Cretaceous and Eocene sediments, showing folded thrust structures. The Gavarnie nappe covers a basement and Mesozoic cover-rock sequence which is exposed in the tectonic windows of La Larri and the Troumouse Cirque. Here, previously unrecognized thrusts involving basement were responsible for folding the overlying Gavarnie nappe. These basement-involved thrusts climb up section westwards giving a westward lowering of the Gavarnie thrust along strike. The structural evolution of the Gavarnie nappe in a region extending from Heas in France to the Valle de Pineta in Spain can be explained in terms of a piggy-back thrusting sequence. On a regional scale, thrust-tectonic models may be used to explain the double vergence of the Pyrenean chain where early southward-directed thrusting was responsible for structures in the South Pyrenean zone. A later northward-directed back thrusting event, or rotation of southward-directed thrust sheets by the stacking of lower thrust horses, can explain the steepness of structures in the axial zone and the northward-verging North Pyrenean thrust zone. Both models suggest that prior to the Pyrenean orogeny, some of the Hercynian structures in the axial zone were flatter lying, and have been rotated to their present steepness during the Pyrenean orogeny. 相似文献
5.
通过对库车前陆盆地的2条MT测线和3条地震剖面的重力二维模拟与综合解释,提高了在复杂变形带进行的构造建模的可靠性。模拟结果表明,库车前陆盆地是以断层相关褶皱作为滑动机制的前陆冲断带。沿下第三系膏盐岩和膏泥岩、侏罗系一三叠系煤系地层发育的滑脱层控制了断层相关褶皱的变形模式,并导致浅层背斜与深部圈闭的位置不一致。在盆地北面,南天山古生界楔入了北部单斜带的中生代地层,导致剩余重力异常值升高;盆地南面,新生界沉积厚度的增加使剩余重力值逐渐降低,局部盐体的堆积可形成重力异常低谷。此外,拜城凹陷基底的密度较高,可能是凹陷形成初期岩浆底侵的结果。推覆变形自天山向塔里木盆地推移,反映了中新世以来逐渐增强的南北向挤压应力和地壳缩短,是印度板块与欧亚板块碰撞的远距离效应。 相似文献
6.
Detailed subsurface structure of the eastern Junggar Basin is investigated using a large number of high-resolution two-dimensional reflection seismic profiles and well data. Our results reveal thrust faults, some of which are with strike-slip component, and fault-related folds dominating the subsurface structure of the study area. The thrust faults mainly show a divergent pattern towards the west and convergence towards the east. We divide these thrust faults and folds into three structural systems. The north thrust system, located in the north of the study area, is characterized by top-to-the southwest imbricate thrusts initiated from late Paleozoic. The central transpression system, dominating the central study area, mainly consists of thrust faults with visible strike-slip component, active from early Mesozoic until Cretaceous. The South thrust system includes top-to-the southeast thrusts in the southern part of the study area. The existence of these structural systems indicates that the eastern Junggar Basin underwent obvious intracontinental deformation in Mesozoic, probably due to the continuous convergence between the Altay and the Tianshan orogens after the main collision-accretion processes of the Central Asian Orogenic Belt. 相似文献
7.
Evolution of the European Cenozoic Rift System: interaction of the Alpine and Pyrenean orogens with their foreland lithosphere 总被引：1，自引：0，他引：1
The evolution of the European Cenozoic Rift System (ECRIS) and the Alpine orogen is discussed on the base of a set of palaeotectonic maps and two retro-deformed lithospheric transects which extend across the Western and Central Alps and the Massif Central and the Rhenish Massif, respectively.During the Paleocene, compressional stresses exerted on continental Europe by the evolving Alps and Pyrenees caused lithospheric buckling and basin inversion up to 1700 km to the north of the Alpine and Pyrenean deformation fronts. This deformation was accompanied by the injection of melilite dykes, reflecting a plume-related increase in the temperature of the asthenosphere beneath the European foreland. At the Paleocene–Eocene transition, compressional stresses relaxed in the Alpine foreland, whereas collisional interaction of the Pyrenees with their foreland persisted. In the Alps, major Eocene north-directed lithospheric shortening was followed by mid-Eocene slab- and thrust-loaded subsidence of the Dauphinois and Helvetic shelves. During the late Eocene, north-directed compressional intraplate stresses originating in the Alpine and Pyrenean collision zones built up and activated ECRIS.At the Eocene–Oligocene transition, the subducted Central Alpine slab was detached, whereas the West-Alpine slab remained attached to the lithosphere. Subsequently, the Alpine orogenic wedge converged northwestward with its foreland. The Oligocene main rifting phase of ECRIS was controlled by north-directed compressional stresses originating in the Pyrenean and Alpine collision zones.Following early Miocene termination of crustal shortening in the Pyrenees and opening of the oceanic Provençal Basin, the evolution of ECRIS was exclusively controlled by west- and northwest-directed compressional stresses emanating from the Alps during imbrication of their external massifs. Whereas the grabens of the Massif Central and the Rhône Valley became inactive during the early Miocene, the Rhine Rift System remained active until the present. Lithospheric folding controlled mid-Miocene and Pliocene uplift of the Vosges-Black Forest Arch. Progressive uplift of the Rhenish Massif and Massif Central is mainly attributed to plume-related thermal thinning of the mantle-lithosphere.ECRIS evolved by passive rifting in response to the build-up of Pyrenean and Alpine collision-related compressional intraplate stresses. Mantle-plume-type upwelling of the asthenosphere caused thermal weakening of the foreland lithosphere, rendering it prone to deformation. 相似文献
8.
The conspicuous curved structures located at the eastern front of the Eastern Cordillera between 25° and 26° south latitude is coincident with the salient recognized as the El Crestón arc. Major oblique strike-slip faults associated with these strongly curved structures were interpreted as lateral ramps of an eastward displaced thrust sheet. The displacement along these oblique lateral ramps generated the local N–S stress components responsible for the complex hanging wall deformation. Accompanying each lateral ramp, there are two belts of strong oblique fault and folding: the upper Juramento River valley area and El Brete area.On both margins of the Juramento River upper valley, there is extensive map-scale evidence of complex deformation above an oblique ramp. The N–S striking folds originated during Pliocene Andean orogeny were subsequently or simultaneously folded by E–W oriented folds. The lateral ramps delimiting the thrust sheet coincident with the El Crestón arc salient are strike-slip faults emplaced in the abrupt transitions between thick strata forming the salient and thin strata outside of it. El Crestón arc is a salient related to the pre-deformational Cretaceous rift geometry, which developed over a portion of this basin (Metán depocenter) that was initially thicker. The displacement along the northern lateral ramp is sinistral, whereas it is dextral in the southern ramp. The southern end of the Eastern Cordillera of Argentina shows a particular structure reflecting a pronounced along strike variations related to the pre-deformational sedimentary thickness of the Cretaceous basin. 相似文献
9.
From surface and subsurface data, line-length and area balancing were used to construct four balanced and restored sections of the Pyrenees. In the Mesozoic cover, a thin-skinned tectonic model is used. In the basement an anticlinal stack geometry is applied for the foreland part of the thrust nappes. We present and discuss three possible models for the deep structures of the belt: a thin-skinned tectonic model, a thick-skinned tectonic model and an inhomogeneous strain model. The thrusts steepen downwards and the displacements die out in ductile deformation deep in the section. Therefore, we use the inhomogeneous strain model and we equal-area balance the surface of the continental crust.Hanging-wall sequence diagrams are constructed taking into account (1) the strong N-S thickness variations of the Mesozoic cover related to the Cretaceous drift of Spain and (2) the related crustal thinning of the North Pyrenean Zone superimposed upon a previous late Hercynian rise of the lower crust.The Moho step at the vertical of the North Pyrenean Fault results from the thinning of the North Pyrenean Zone. The thickening of both the Axial Zone and the North Pyrenean Zone during the Eocene compressional event preserved the step geometry.Calculated values of the minimum shortening range from 55 km in the western part of the belt to 80 km in the eastern part. Most of the shortening occurs south of the North Pyrenean Fault in the eastern part (Axial Zone) and north of the North Pyrenean Fault in the western part (Labourd thrust). 相似文献
10.
Many mountain belts exhibit significant along‐strike variation in structural style with changes in the width of the orogen, the geometry and kinematics of the crustal‐scale thrust system, and the degree of partitioning between pro‐ and retro‐wedge deformations. Although the main factors controlling first‐order structural style are understood, the cause of these lateral variations remains to be resolved. Here we focus on the Pyrenees, characterized by significant lateral variation in structural style with a thrust system involving more and thinner thrust sheets in the eastern section than in the western part. Similarly, the prior Mesozoic rifting event was characterized by significant lateral variation in structure. We integrate available geological and geophysical data with forward lithospheric scale numerical models. We show that lateral variation in crustal strength attributed to inherited Variscan crustal composition accentuated during Mesozoic rifting explains the variation in structural style observed during Pyrenean mountain building. 相似文献
11.
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
12.
M.W. Fischer 《Journal of Structural Geology》1984,6(6):721-726
Balanced and restored cross-sections through the central and eastern Pyrenees, constructed using both surface and borehole data, demonstrate the presence of c.18km of shortening above a flat lying N-directed Alpine décollement surface. Hangingwall diagrams show how the North Pyrenean satellite massifs are culminations within this thrust system. Pre-thrusting structures such as subhorizontal stretching lineations in the North Pyrenean Fault zone became rotated above these culminations as the North Pyrenean Fault was cut by Alpine thrusts. Stratigraphic evidence demonstrates that N-directed thrust movements occurred between mid Eocene and Oligocene time, and this is similar to the age of major S-directed thrust movements on the south side of the Axial Zone. The N-directed thrust system probably originated as a series of backthrusts to the dominant S-directed structures. 相似文献
13.
14.
Analysis of a suite of 2-D seismic reflection profiles reveals that the northwestern Sacramento Valley and eastern Coast Range foothills, northern California, are underlain by a system of blind, west-dipping thrust faults. Homoclinally east-dipping and folded Mesozoic marine forearc strata exposed along the western valley margin define the forelimbs of northeast-vergent fault-propagation folds developed in the hanging walls of the thrusts. Exhumed coherent blueschists of the accretionary complex and attenuated remnants of the ophiolitic forearc basement presently exposed in the eastern Coast Ranges are in the hanging wall of the blind thrust system, and have been displaced from their roots in the footwall. Deep, east-dipping magnetic reflectors in the footwall of the thrust system may be fragments of sheared, serpentinized and attenuated ophiolitic basement. Restoration of slip on the thrusts suggests that the Coast Range fault, which is the exposed structural contact between the coherent blueschists and attenuated ophiolite, originally dipped east and is associated with the east-dipping magnetic reflectors in the footwall. This interpretation of the reflection data is consistent with previous inferences about the deep structure in this region, and supports a two-stage model for blueschist exposure in the eastern Coast Ranges: (1) blueschist exhumation relative to the forearc basin by attenuation of the ophiolitic basement along the east-dipping Coast Range fault system in late Cretaceous; (2) blueschists, attenuated ophiolite, and forearc strata all were subsequently uplifted and folded in the hanging wall of the blind thrust system beginning in latest Cretaceous–early Tertiary. The blind thrust system probably rooted in, and was antithetic to, the east-dipping subduction zone beneath the forearc region. Active transpressional plate motion in western California is locally accommodated, in part, by reactivation of blind thrust faults that originally developed during the convergent regime. 相似文献
15.
B.R. Goleby R.S. Blewett R.J. Korsch D.C. Champion K.F. Cassidy L.E.A. Jones P.B. Groenewald P. Henson 《Tectonophysics》2004,388(1-4):119
Deep seismic reflection data across the Archaean Eastern Goldfields Province, northeastern Yilgarn Craton, Western Australia, have provided information on its crustal architecture and on several of its highly mineralised belts. The seismic reflection data allow interpretation of several prominent crustal scale features, including an eastward thickening of the crust, subdivision of the crust into three broad layers, the presence of a prominent east dip to the majority of the reflections and the interpretation of three east-dipping crustal-penetrating shear zones. These east-dipping shear zones are major structures that subdivide the region into four terranes. Major orogenic gold deposits in the Eastern Goldfields Province are spatially associated with these major structures. The Laverton Tectonic Zone, for example, is a highly mineralised corridor that contains several world-class gold deposits plus many smaller deposits. Other non crustal-penetrating structures within the area do not appear to be as well endowed metallogenically as the Laverton structure. The seismic reflection data have also imaged a series of low-angle shear zones within and beneath the granite–greenstone terranes. Where the low-angle shear zones intersect the major crustal-penetrating structures, a wedge shaped geometry is formed. This geometry forms a suitable fluid focusing wedge in which upward to subhorizontal moving fluids are focused and then distributed into the nearby complexly deformed greenstones. 相似文献
16.
雪峰山西部中生代厚皮逆冲推覆构造样式与变形特征研究 总被引：2，自引：0，他引：2
雪峰山厚皮逆冲推覆构造带位于扬子地块东南缘,由南向北,主构造线走向由北北东向渐变为北东东向,形成向北西突出的弧形。构造带内基底新元古界板溪群大面积出露,这些基底出露的原因和构造方式是华南中生代大地构造分析的核心问题之一。以野外构造解析为基础,结合相关地球物理资料解释,对雪峰山西部逆冲推覆构造的构造样式与变形序列进行了系统的解析。结果表明,雪峰山构造带从印支期开始发育由南东向北西的大规模的逆冲推覆构造,逆冲断层在近地表向南东陡倾,向下逐渐收敛于基底内的滑脱断层之上。基底新元古界板溪群及早古生界均卷入了推覆构造,同时逆冲覆盖于中生代地层之上,形成厚皮构造,并造成了基底板溪群的大面积出露。 相似文献
17.
Apatite fission track analysis was performed on 56 samples from central Spain to unravel the far field effects of the Alpine plate tectonic history of Iberia. The modelled thermal histories reveal complex cooling in the Cenozoic, indicative of intermittent denudation. Accelerated cooling events occurred across the Spanish Central System (SCS) from the Middle Eocene to Recent. These accelerated cooling events resulted in up to 2.8±0.9 km of denudation in the western Sierra de Gredos and 3.6±1.0 km in the central and eastern Gredos (assuming a paleogeothermal gradient of 28±5 °C and a surface temperature of 10 °C). The greatest amount of denudation (5.0±1.6 km) occurred in the Sierra de Guadarrama. Accompanying rock uplift was 4.7±1.0 and 5.9±1.6 km in the eastern Gredos and Guadarrama, respectively. Most denudation in the Gredos occurred from the Middle Eocene to the Early Miocene and can be related to the N–S stress field, induced by the Pyrenean compression. In the Guadarrama, the greatest denudation was Pliocene to Recent of age and seems related to the ongoing NW–SE Betic compression. The fact that the formation of the E–W trending Gredos coincides with the N–S Pyrenean compression and the creation of the present day morphology of the NE–SW trending Guadarrama with the younger NW–SE Betic compression, indicates that they record the far field effects of Alpine plate tectonics on Iberia. The trend of pre-existing lineaments was of major importance in influencing the style and magnitude of these of far field effects. 相似文献
18.
正确识别南海东南部中生界及其分布,对认识南海形成演化和油气资源潜力具有重要意义。受资料条件约束和地层系统划分差异的影响,南海东南部中生界分布和构造特征一直存在争议。本文在钻井、拖网约束下,通过井震对比、地震反射特征、层速度分析、岩浆岩体与地层接触关系和构造变形特征来综合识别中生界。结果表明,中生界呈平行、连续、低频的反射特征,层速度3400~4200 m/s,随着埋深或（和）变质程度增强,层速度增大（4500~5500 m/s）,反射波组模糊,多数未见明显底界反射。研究区中生代地层发育局限,地震反射波组特征明显,但较难进行区域对比和解释。其中,西北、西南巴拉望盆地、礼乐滩和安渡北盆地中生界呈现低角度掀斜或近水平层状;礼乐滩西南部九章盆地中生界层速度3500~4500 m/s,高于上覆新生界,与钻井层速度吻合,地层呈高角度掀斜或挠曲变形,可能与岩浆活动侵位相关。结合中生代火山弧和识别的岩体分布,推测前者零散分布在弧前盆地靠火山弧一侧,构造活动相对弱,后者分布于岩浆活动强烈的弧间盆地。 相似文献
19.
The Tan-Lu fault zone (TLFZ) traverses the Liaohe western depression (LHWD), affords an exceptional opportunity to reveal the structural deformation and evolution of a major strike-slip fault of the LHWD using three dimensional seismic data and well data. In this paper, based on structural interpretations of the 3-D seismic data of the LHWD, combined with depth slice and seismic coherency, a variety of structural features in relation to right-lateral strike-slip fault (the western branch of the Tan-Lu fault) have been revealed presence in the depression, such as thrust faults (Xinlongtai, Taian-Dawa, and Chenjia faults), structural wedges, positive flower structures, and en echelon normal faults. Fault cutoffs, growth strata and the Neogene unconformity developed in the LHWD verify that the activity of right-lateral strike-slip from the late Eocene to Neogene (ca. 43–23 Ma). The study indicates that the right-lateral strike-slip played an important role in controlling the structural deformation and evolution of the LHWD in the early Cenozoic. Moreover, the front structural wedge generated the gross morphology of the Xinlongtai anticline and developed the Lengdong faulted anticline during the late Eocene, and the back structural wedge refolded the Lengdong faulted anticline zone in the late Eocene to the early Oligocene. Wrench-related structures (the Chenjia thrust fault and the en echelon normal faults) were developed during the late Oligocene. Uniform subsidence in the Neogene to Quaternary. Furthermore, the driving force of the right-lateral strike-slip deformation was originated from N–S extension stress related to the opening of the Japan Sea and NE–SW compression, as the far-field effect of India–Eurasia convergence. 相似文献
20.
A new species of the foraminiferal genus Pseudorhapydionina is reported from the Santonian shallow-water carbonate and mixed deposits of La Cova Unit, in the Montsec and Pedraforca thrust sheets (Southern Pyrenees, NE Spain). Pseudorhapydionina bilottei sp. nov. differs from the Cenomanian species of the genus in its larger test size and the number of chambers in its early planispiral-involute stage. The discovery of P. bilottei sp. nov in the Santonian indicates that the genus Pseudorhapydionina escaped extinction during the Cenomanian-Turonian boundary (CTB) event in the Pyrenean bioprovince. A new subfamily Pseudorhapydionininae is described. 相似文献