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1.
Mechanical stratigraphy as a factor controlling the development of a sandbox transfer zone: a three-dimensional analysis 总被引：3，自引：0，他引：3
In thrust belts, fold–fault terminations are common features of the structural architecture and can pose complicated problems to unravel, in particular when two or more terminations are in close proximity. Such terminations usually reflect pre-existing attributes. Amongst the many factors, lateral variations in the mechanical stratigraphy can control along-strike geometry and kinematics of fault-related folds.A displacement transfer zone was produced in a compressional sandbox model by means of two adjacent, mechanically different stratigraphic domains. The experiment allowed two discrete chains to develop in the different domains, so that a complex structural setting occurred in the connecting area. Periclinal folds, oblique thrust fronts and oblique ramps developed in the resulting transfer zone. The interaction between periclines in the transfer zone produced lateral culminations in the folded structures. The analysis of displacement across the structural domains revealed that a significant loss of slip along the faults occurred in the relay zone. In this area, imbricate faulting was partially replaced by layer-parallel shortening. A linear relationship appears to exist between the bed length of the thrust sheet and the related fault slip. 相似文献
2.
塔里木盆地库车、塔西南和塔东南山前带在构造变形和活动强度等方面存在较大的差异性,这也决定了油气地质条件与油气分布的不均衡性。通过对3个山前带地质剖面的对比研究,结合对典型成藏模式的剖析,探讨山前带差异构造变形特征对油气成藏的控制作用。库车山前带以逆冲推覆及盐构造为主,构造圈闭规模大、幅度高;主要有盐下和盐上两种成藏模式,通源断裂十分发育,库姆格列木组膏盐岩对盐下油气的保存非常有利。塔西南山前带变形分段特征明显,包括三角带构造、双重逆冲、叠加背斜等,构造圈闭规模和完整性不如库车山前带;成藏模式也体现出分段差异,上白垩统-阿尔塔什组膏泥岩和普司格组泥岩的封闭效果较好,但运移路径复杂,先存油气易遭受后期调整和破坏。塔东南山前带具有一定构造分段性,若羌凹陷山前以冲断变形为主,远离山前的第二排背斜、断背斜圈闭具备基本的成藏条件;民丰凹陷山前以叠瓦逆冲和三角带构造为主,古近系膏泥岩封盖能力有限,深部逆冲断块及凹陷内部的低幅度背斜等是较现实的勘探目标。 相似文献
3.
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
4.
Modern seismic data indicate that the sole fault of the Turner Valley thrust sheet does not lose displacement in an up-dip direction and that it does not crop out but rather flattens into the triangle zone on the eastern edge of the Rocky Mountain Foothills Belt. Well constrained balanced cross-sections drawn through this part of the belt do not incorporate significant folding related to the propagation of thrust faults. 相似文献
5.
湘西—鄂西成矿带自新太古界至第四系均有发育。依据大地构造演化特征,结合地层发育特征及岩相古地理,按青白口纪和南华纪—震旦纪两个阶段进行地层区划分。青白口纪时期,研究区分为南秦岭地层区、黄陵地层区、梵净山地层区、武陵-雪峰地层区与四川盆地区。南华纪-震旦纪时期,研究区分为南秦岭地层区武当地层分区、陨均台地层分区及扬子地层区湘黔鄂地层分区、湘中分区。对成矿带岩石地层提出了对比方案,主要为:石桥铺组和黄狮洞组来替代甲路组;沿用乌叶组而弃用砖墙湾组;重新定义清水江组,将以板岩为主的地层都归属清水江组,相当于番召组上段、清水江组、平略组之和;保留原清水江组之上的隆里组而弃用平略组(黔)和岩门寨组(湘);弃用陨均台地区的"陡山沱组"和"灯影组",沿用尚家店组和青山寨组的定名;采用老堡组来替代留茶坡组。 相似文献
6.
南大巴山前陆冲断带构造样式及变形机制分析 总被引：35，自引：9，他引：26
大巴山构造带位于秦岭造山带和四川盆地的过渡部位,形成于印支-燕山期,定型于喜山期。按照构造变形样式及其组合特征,从北东向南西可依次划分为北大巴山逆冲推覆构造带、南大巴山前陆褶皱-冲断带(又包括叠瓦断层带、断层-褶皱带和滑脱褶皱带等3个亚带)和四川盆地东北部低缓构造区等3个构造带(区)。南大巴山冲断带地表构造以类侏罗山式褶皱为显著特征,主要发育叠瓦断层系、断层相关褶皱、被动顶板双重构造、反冲断层系和冲起构造等变形样式。北东-南西向挤压应力和滑脱层是控制南大巴山及其前缘构造变形的主要因素,结合区域地质研究成果,建立了南大巴山及其前缘地区依次从震旦系-下寒武统-志留系-中下三叠统逐渐抬高的多层次滑脱前展模式。 相似文献
7.
东秋里塔格构造带是塔里木盆地库车坳陷的前缘构造带,整体表现为受新近系吉迪克组膏盐岩滑脱层控制的分层变形构造特征。盐上构造层主要发育断层相关褶皱,盐岩层以塑性流动变形为主,盐下构造层发育断层相关褶皱、冲起构造、逆冲断块等多种构造样式。依据盐下构造层变形特征,自西向东将东秋里塔格构造带划分为过渡构造段、叠瓦扇构造段、前端冲起构造段以及后端冲起构造段四段。过渡构造段内膏盐岩层发育层位由库姆格列木群转变为吉迪克组,盐下发育叠瓦扇构造;叠瓦扇构造段盐下发育典型的逆冲叠瓦构造样式;前端冲起构造段盐下发育断弯褶皱背斜,并在反冲断层的复合作用下发生冲起,主逆冲断层之下发育次级逆冲夹片;后端冲起构造段盐下发育断弯褶皱,并在背斜北翼发育一个独立的冲起构造。东秋里塔格构造带具备有利生储条件,构造分析表明过渡构造段、叠瓦扇构造段以及前端冲起构造段的盐下次级逆冲夹片具备勘探潜力,是有利的油气勘探区带。 相似文献
8.
The map expression of "abrupt" changes in lateral stratigraphic level of a thrust fault has been traditionally interpreted to be a result of the presence of(1) a lateral(or oblique) thrust-ramp,or(2) a frontal ramp with displacement gradient、and/or(3) a combination of these geometries.These geometries have been used to interpret the structures near transverse /ones in fold-thrust belts(FTB).This contribution outlines an alternative explanation that can result in the same map pattern by lateral variations in stratigraphy along the strike of a low angle thrust fault.We describe the natural example of the Leamington transverse zone.which marks the southern margin of the Pennsy lvanian—Permian Oquirrh basin with genetically related lateral stratigraphic variations in the North American Sevier(TB.Thus.the observed map pattern at this zone is closely related to lateral stratigraphic variations along the strike of a horizontal fault.Even though the present-day erosional level shows the map pattern that could be interpreted as a lateral ramp.the observed structures along the Leamington zone most likely share the effects of the presence of a lateral(or oblique) ramp,lateral stratigraphic variations along the fault trace.and the displacement gradient. 相似文献
9.
塔西南坳陷甫沙构造带褶皱冲断强烈,古近系膏泥岩下层构造变形复杂,具有正反转构造变形特征。侏罗纪—白垩纪区域伸展环境发育大量正断层,后期在喜马拉雅运动中受挤压反转。南部发育高角度基底卷入正反转断层,中部发育叠瓦式逆冲断层,北部边缘变形微弱。相应地将甫沙构造带划分为反转断隆背斜带、楔状叠瓦构造带和逆冲前缘构造带;反转程度南强北弱、西强东弱。对区域构造变形环境的分析表明,西昆仑山隆升引发水平挤压叠加垂直向上的剪切作用,使先存高角度正断层容易被迁就利用进而发生正反转。对正反转相关构造圈闭评价认为:反转断隆背斜带发育的圈闭规模大,幅度低,埋藏浅,落实程度高,但上覆膏泥岩层薄,被断层破坏强烈,油气散失严重;楔状叠瓦构造带发育的圈闭规模小,幅度大,埋藏深,落实程度低,上覆膏泥岩层厚,有利于油气保存;逆冲前缘构造带发育低幅度隆起和地层岩性圈闭。 相似文献
10.
Florian Genier Jean-Luc Epard François Bussy Tomas Magna 《Swiss Journal of Geoscience》2008,101(2):431-452
Detailed field work and zircon analysis have improved the knowledge of the lithostratigraphy at the base of the Siviez-Mischabel nappe in the Mattertal (St-Niklaus-Törbel area). They confirm the existence of an overturned limb and clarify the structure of the St-Niklaus syncline. The following formations can be observed:
- Polymetamorphic gneisses; composed of paragneisses, amphibolites and micaschists (Bielen Unit, pre-Ordovician).
- Fine-grained, greyish quartzite and graywacke with kerogen-rich horizons (Törbel Formation, presumed Carboniferous).
- Green or white micaschists characterized by brown carbonate spots associated with white conglomeratic quartzites (Moosalp Formation, Early Permian).
- Massive, green or white, fine grained, microconglomeratic or conglomeratic quartzites with characteristic pink quartz pebbles (Bruneggjoch Formation, Late Permian-Early Triassic).
11.
本文以Vail的经典层序地层学和Cross的高分辨率层序地层学理论方法为指导,通过对层序界面、相序、叠置结构、测井曲线等标志的综合识别分析,将研究区长兴组划分为两个三级层序。在长兴组三级层序格架剖面建立的基础上,建立了长兴组层序地层演化模式,并从层序演化的角度探讨了长兴组沉积时期礁滩体的发育分布规律。 相似文献
12.
车排子凸起位于准噶尔盆地扎伊尔山前,是夹持在南部四棵树凹陷和东部沙湾凹陷之间的三角构造带。然而对这个三角构造带是原地掩伏构造,山前推覆构造,还是走滑构造控制形成的认识存在争议。目前对于车排子凸起与沙湾凹陷过渡带的构造变形特征以及变形机制的认识尚不清楚。而过渡带是研究该区构造变形与演化的良好区域,精细研究该区域构造几何学与运动学对于揭示其构造变形机制以及认识盆山之间的关系具有积极作用,并对于该区油气勘探具有重要意义。本文以研究区的连片三维地震资料为基础,运用不整合面识别、轴面分析及平衡剖面等方法,对车排子凸起与沙湾凹陷过渡带进行精细的构造解析、建模与构造复原。研究表明,过渡带发育下二叠统（P1j-P1f）,中二叠统（P2x-P2w）,上二叠统（P3w）,三叠系（T）,侏罗系（J）,白垩系（K）与古近系-第四系（E-Q）7个构造变形层序。发育佳木河组底部及石炭系内部滑脱层。深部（前二叠系）构造楔发育于整个过渡带,其个数和几何学形态的变化直接影响了上覆背斜形态。构造楔在早二叠世开始楔入,挤压作用持续至三叠纪末期。晚三叠世发育生长地层,显示了P-T构造层褶皱变形的时间,随后三叠纪末期,过渡带受到来自西北缘造山带方向的逆冲推覆构造的叠加作用,表现在后缘发育一系列叠瓦构造,推覆距离约为8 km,南部逆冲断层上盘二叠系-三叠系被剥蚀完全,北部残余少量下二叠统佳木河组。 相似文献
13.
14.
Existence of a possible detachment zone at Elampillai region, NW margin of Kanjamalai Hills, located in the northern part of Cauvery Suture Zone (CSZ), Southern India, is reported here for the first time. Detailed structural mapping provides anatomy of the zone, which are rarely preserved in Precambrian high grade terranes. The detachment surface separates two distinct rock units of contrasting lithological and structural characters: the upper and lower units. The detachment zone is characterized by a variety of fold styles with the predominance of tight isoclinal folds with varied plunge directions, limb rotations and the hinge line variations often leading to lift-off fold like geometries and deformed sheath folds. Presence of parasitic folding and associated penetrative strains seem to be controlled by differences in mechanical stratigraphy, relative thicknesses of the competent and incompetent units, and the structural relief of the underlying basement. Our present study in conjunction with other available geological, geochemical and geochronological data from the region indicates that the structures of the detachment zone are genetically related to thrust tectonics forming a part of subduction–accretion–collision tectonic history of the Neoproterozoic Gondwana suture. 相似文献
15.
16.
Evidence for Neotethys rooted within the Vardar suture zone from the Voras Massif, northernmost Greece 总被引：2，自引：0，他引：2
Three conflicting models are currently proposed for the location and tectonic setting of the Eurasian continental margin and adjacent Tethys ocean in the Balkan region during Mesozoic–Early Tertiary time. Model 1 places the Eurasian margin within the Rhodope zone relatively close to the Moesian platform. A Tethyan oceanic basin was located to the south bordering a large “Serbo-Pelagonian” microcontinent. Model 2 correlates an integral “Serbo-Pelagonian” continental unit with the Eurasian margin and locates the Tethys further southwest. Model 3 envisages the Pelagonian zone and the Serbo-Macedonian zone as conjugate continental units separated by a Tethyan ocean that was sutured in Early Tertiary time to create the Vardar zone of northern Greece and former Yugoslavia. These published alternatives are tested in this paper based on a study of the tectono-stratigraphy of a completely exposed transect located in the Voras Mountains of northernmost Greece. The outcrop extends across the Vardar zone, from the Pelagonian zone in the west to the Serbo-Macedonian zone in the east.Within the Voras Massif, six east-dipping imbricate thrust sheets are recognised. Of these, Units 1–4 correlate with the regional Pelagonian zone in the west (and related Almopias sub-zone). By contrast, Units 5–6 show a contrasting tectono-stratigraphy and correlate with the Paikon Massif and the Serbo-Macedonian zone to the east. These units form a stack of thrust sheets, with Unit 1 at the base and Unit 6 at the top. Unstacking these thrust sheets places ophiolitic units between the Pelagonian zone and the Serbo-Macedonian zone, as in Model 3. Additional implications are, first, that the Paikon Massif cannot be seen as a window of Pelagonian basement, as in Model 1, and, secondly, Jurassic andesitic volcanics of the Paikon Massif locally preserve a gneissose continental basement, ruling out a recently suggested origin as an intra-oceanic arc.We envisage that the Almopias (Vardar) ocean rifted in Triassic time, followed by seafloor spreading. The Almopias ocean was consumed beneath the Serbo-Macedonian margin in Jurassic time, generating subduction-related arc volcanism in the Paikon Massif and related units. Ophiolites were emplaced onto the Pelagonian margin in the west and covered by Late Jurassic (pre-Kimmeridgian) conglomerates. Other ophiolitic rocks formed within the Vardar zone (Ano Garefi ophiolite, Unit 4) in latest Jurassic–Early Cretaceous time and were not deformed until Early Tertiary time. The Vardar zone finally sutured in the Early Tertiary creating the present imbricate thrust structure of the Voras Mountains. 相似文献
17.
构造转换带在逆冲断裂带中具有调节主干逆冲断层之间位移的作用。根据相邻主干逆冲断层在剖面上的组合关系并结合塔里木盆地中央隆起区的研究成果,将挤压区构造转换带分为相向倾斜、背向倾斜和同向倾斜型3类。相向倾斜型在转换带部位发育背冲断块样式,背向倾斜型通过逆冲三角带实现逆冲断层的倾向转换,同向倾斜型通过叠瓦构造实现断层位移的转换。分析了影响构造转换带形成的因素,认为基底构造、滑脱层、沉积相与岩性差异以及应力作用方式等对转换带形成具有重要影响。构造转换带是构造变形相对复杂的区带,不仅控制着富有机质沉积物的分布,形成有利的油气聚集区带,而且密集的断裂系也为烃类的运移提供了通道,并且有利于发育与断层、背斜有关的各种构造圈闭。 相似文献
18.
The Daba Mountains define the southern margin of the East Qinling orogenic belt, and form the boundary of the Sichuan basin
in the north and northeast. The Daba Mountains can be divided into two structural belts by the NW-striking Chengkou fault,
namely the northern Dabashan thrust-nappe belt and the southern Dabashan foreland fold-and-thrust belt. The southern Dabashan
fold-and-thrust belt is a southwestward extruding thin-skinned thrust wedge, showing obvious belted change in deformation
style and deformation intensity along the dip direction, and can be divided further into three sub-belts, i.e. the imbricate
thrust sub-belt characterized by imbricate stepped-thrust sheets, the thrust-fold sub-belt characterized by the combination
of the equally-developed thrusts and related folds, and the detachment-fold sub-belt characterized by box folds and closed
overturned-isoclinal folds on the outcrops. Several kinds of structures have been recognized or inferred, including imbricate
thrust system, passive-roof duplex (triangle zone), fault-related folds, back-thrust system and pop-up structure. The NE-SW
compressive stress from the Qinling orogenic belt and detachment layers in the covering strata are the two most important
determinants of deformation style. After the collision between the North China block and Yangtze block at the end of the Middle
Triassic, the northward intracontinental subduction along the southern edge of the Qinling orogenic belt was initiated, which
led to the corresponding southward thrusting in the upper crust. The thrusting propagated towards the foreland through the
Jurassic and extended to the southernmost part of the southern Daba Mountains around the end of the Early Cretaceous, with
thrusting deformation to be preferentially developed along major detachment layers and progressing upwards from the Lower
Sinian through the Lower Cambrian and Silurian to Middle-Lower Triassic.
Translated from Geotectonica et Metallogenia, 2006, 30(3): 294–304 [译自: 大地构造与成矿学] 相似文献
19.
南大巴山前陆冲断带自北向南发育了根带、中带和锋带三条构造带。通过对处于中带的木瓜口-明月乡、城口-龙田乡两段剖面地质考察,结果表明该剖面叠瓦断层带经历了七期运动:三期NE-SW向的前展式逆冲运动,一期SE-NW右旋剪切运动,一期EW逆冲右旋运动,一期NE-SW向的左旋走滑运动及NE-SW向的正断运动,同时受到NW-SE的右旋剪切作用。结合前人年代学研究结果,初步探讨了剖面的变形机制,研究结果对南大巴山前陆褶断带的构造格架、矿产形成及油气分布远景研究均有一定的指导作用。 相似文献
20.
南昆仑造山带西段发育逆冲推覆构造、平行走滑构造、地垒一地堑构造和阿尔卑斯式褶皱、侏罗山式褶皱,前两类构造尚有韧性剪切带伴生;其构造组合在平面上具有内带一外带一前陆带明显的分带性,且形成了逆冲推覆构造一平行走滑构造一地垒一地堑构造的构造序列。 相似文献