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1.
We constructed a geological map, a 3D model and cross-sections, carried out a structural analysis, determined the stress fields and tectonic transport vectors, restored a cross section and performed a subsidence analysis to unravel the kinematic evolution of the NE emerged portion of the Asturian Basin (NW Iberian Peninsula), where Jurassic rocks crop out. The major folds run NW-SE, normal faults exhibit three dominant orientations: NW-SE, NE-SW and E-W, and thrusts display E-W strikes. After Upper Triassic-Lower Jurassic thermal subsidence, Middle Jurassic doming occurred, accompanied by normal faulting, high heat flow and basin uplift, followed by Upper Jurassic high-rate basin subsidence. Another extensional event, possibly during Late Jurassic-Early Cretaceous, caused an increment in the normal faults displacement. A contractional event, probably of Cenozoic age, led to selective and irregularly distributed buttressing and fault reactivation as reverse or strike-slip faults, and folding and/or offset of some previous faults by new generation folds and thrusts. The Middle Jurassic event could be a precursor of the Bay of Biscay and North Atlantic opening that occurred from Late Jurassic to Early Cretaceous, whereas the Cenozoic event would be responsible for the Pyrenean and Cantabrian ranges and the partial closure of the Bay of Biscay. 相似文献
2.
Chahreddine Naji Amara Masrouhi Zayneb Amri Mohamed Gharbi Olivier Bellier 《Arabian Journal of Geosciences》2018,11(19):583
New stratigraphic data, lithostratigraphic correlations, and fault kinematic analysis are used to discuss the basin geometry and sedimentation patterns of the northeastern Tunisia during Cretaceous times. Significant facies and thickness variations are deduced along the northeastern Atlas of Tunisia. The NW-SE 80-km-long regional correlation suggests a high sedimentation rate associated with irregular sea floor. The fault kinematic analysis highlights N-S to NE-SW tectonic extension during Early Cretaceous. During Aptian–Albian times, an extensional regime is recognized with NE-SW tectonic extension. The Cenomanian–Turonian fault populations highlight a WNW-ESE to NW-SE extension, and Campanian–Maastrichtian faults illustrate an NW-SE extension. The normal faulting is associated to repetitive local depocenters with a high rate of sedimentation as well as abundant syntectonic conglomeratic horizons, slump folds, and halokinetic structures. The sequence correlation shows repetitive local depocenters characterizing the basin during Early Cretaceous times. All the above arguments are in favor of basin configuration with tilted blocks geometry. This geometry is shaped by major synsedimentary intra-basin listric normal faults, themselves related to the extensional setting of the southern Tethyan paleomargin, which persisted into the Campanian–Maastrichtian times. The results support a predominant relationship between tilted blocks geometry and sedimentation rather than E-W “Tunisian trough” as it was previously accepted. 相似文献
3.
Eric Barrier Samir Bouaziz Jacques Angelier Gilles Creuzot Jamel Ouali Pierre Tricart 《Geodinamica Acta》2013,26(1):39-57
AbstractA detailed analysis of brittle deformations in the Saharian platform of southern Tunisia is based on studies of fault-slip data sets and joint sets. It allows reconstruction of the Mesozoic paleostress evolution. During the Permo-Triassic, N-S extensions occurred with high late Permian subsidence rates. During the Norian, strike-slip movements reactivated former normal faults. During the Jurassic and the Cretaceous a succession of extensional events was characterized by : (1) a N-S extension which dominated from late Triassic to early Aptian. We relate this extension to the Africa-Eurasia divergence; (2) a ENE-WSW extension during the Cenomanian. We relate this extension to the opening of «he African basins ; (3) a NE-SW Senonian extension that continued during the Cenozoic in the Jeffara and in the Gabes Gulf, during the further evolution of the northern African margin. The various compressional trends recorded in the platform are attributed to Cenozoic events. 相似文献
4.
东三江盆地南部白垩纪以来的沉积特征及其演化 总被引：1，自引：0，他引：1
东三江地区白垩纪以来的沉积特征及其演化,对大庆外围地区的油气勘探和揭示东北亚地区演化机制具有重要意义。根据岩心、录井、测井以及地震等资料的详细研究表明：白垩纪以来均发育扇三角洲-湖泊沉积体系。早白垩世为弧后伸展型盆地,残留地层中有滨浅湖和火山岩沉积;晚白垩世为北东向展布的板内挠曲挤压型盆地,发育以盆地两侧绥滨和完达山为物质供给的短轴物源,海浪组－七星河组发育逆同生断层,半深湖的面积先扩大后缩小,雁窝组以盆地充填消亡为主。新生代为右旋走滑拉分盆地,以继承性的短轴物源为主。在宝泉岭组时期有桦南隆起方向的长轴物源,宝泉岭组－富锦组下、中段,半深湖面积扩大,沉积中心向东南迁移;富锦组上段,水体变浅,湖盆面积扩大,沉积中心向西北迁移。 相似文献
5.
六盘山盆地夹于鄂尔多斯地块、青藏地块和阿拉善地块之间,在中国大地构造体系中处于独特的构造位置。基于野外变形分析与断层滑动矢量构造应力场反演,初步确定了六盘山盆地形成与构造演化历史。结果表明,六盘山盆地主要经历了早白垩世成盆过程和后期改造过程2个大的阶段。早白垩世早期,受到区域近E-W向引张应力作用而发生断陷,盆内沉积了一套巨厚的河湖相六盘山群;早白垩世晚期在NW-SE向挤压下,断陷盆地发生构造反转,局部地区褶皱回返,六盘山群发生不同程度的断裂和褶皱变形,继而盆地开始了长期的隆升剥蚀作用。晚新生代,受到印度—欧亚大陆碰撞产生的远程效应,六盘山盆地先后经历了NE-SW向和近E-W向挤压应力作用,盆地发生了强烈的褶皱和断裂变形,六盘山快速隆起。六盘山盆地构造应力场演化历史不仅为研究周缘地块的运动学和动力学提供构造地质依据,也对盆地油气勘探具有指导意义。 相似文献
6.
Abstract3D stratigraphic geometries of the intracratonic Meso- Cenozoic Paris Basin were obtained by sequence stratigraphic correlations of around 1 100 wells (well-logs). The basin records the major tectonic events of the western part of the Eurasian Plate, i.e. opening and closure of the Tethys and opening of the Atlantic. From earlier Triassic to Late Jurassic, the Paris Basin was a broad subsiding area in an extensional framework, with a larger size than the present-day basin. During the Aalenian time, the subsidence pattern changes drastically (early stage of the central Atlantic opening). Further steps of the opening of the Ligurian Tethys (base Het- tangian, late Pliensbachian;...) and its evolution into an oceanic domain (passive margin, Callovian) are equally recorded in the tectono-sedimentary history. The Lower Cretaceous was characterized by NE-SW compressive medium wavelength unconformities (late Cimmerian-Jurassic/Cretaceous boundary and intra- Berriasian and late Aptian unconformities) coeval with opening of the Bay of Biscay. These unconformities are contemporaneous with a major decrease of the subsidence rate. After an extensional period of subsidence (Albian to Turanian), NE-SW compression started in late Turanian time with major folding during the Late Cretaceous. The Tertiary was a period of very low subsidence in a com- pressional framework. The second folding stage occurred from the Lutetian to the Lower Oligocene (N-S compression) partly coeval with the E-W extension of the Oligocene rifts. Further compression occurred in the early Burdigalian and the Late Miocene in response to NE-SW shortening. Overall uplift occurred, with erosion, around the Lower/Middle Pleistocene boundary. © 2000 Éditions scientifiques et médicales Elsevier SAS 相似文献
7.
华南中-新生代构造演化受太平洋构造域和特提斯洋构造域的联合控制.以江南东段NE-SW向景德镇-歙县剪切带和球川-萧山断裂中发育的脆性断层为研究对象,利用野外交切关系和断层滑移矢量反演方法厘定了7期构造变形序列并反演了各期古构造应力场,讨论了断层活动的时代及其动力学.白垩纪至新生代研究区7期古构造应力场分别为:(1)早白垩世早期(136～125Ma)NW-SE向伸展;(2)早白垩世晚期(125～107Ma)N-S向挤压和E-W向伸展;(3)早白垩世末期至晚白垩世早期(105～86Ma)NW-SE向伸展;(4)白垩世中期(86～80Ma)NW-SE向挤压和NE-SW向伸展;(5)晚白垩世晚期至始新世末期(80～36Ma)N-S向伸展;(6)始新世末期至渐新世早期(36～30Ma)NE-SW向挤压和NW-SE向伸展;(7)渐新世早期至中新世中期(30～17Ma)NE-SW向伸展.结合区域地质研究表明,第1期至第4期古构造应力场与古太平洋构造域的板片后撤、俯冲以及微块体(菲律宾地块)间的碰撞作用有关;第5期伸展作用受控于新特提斯构造域俯冲板片后撤,而第6期和第7期古构造应力场主要与印-亚碰撞的远程效应有关.白垩纪至新生代,华南东部受伸展构造体制和走滑构造体制的交替控制.先存断裂的发育可能是导致华南晚中生代走滑构造体制的主要控制因素. 相似文献
8.
渤海湾盆地黄骅坳陷中北区新生代幕式沉降过程 总被引：4，自引：0，他引：4
黄骅坳陷中北区是位于渤海湾盆地中部的一个重要新生代构造单元.构造层序界面分析、同生断裂活动和盆地沉降史回剥分析表明该区经历了幕式沉降过程,沉降中心显示出规律性的迁移演化特征.馆陶组底界面为区域性裂后不整合界面,将研究区的演化划分为裂陷期和裂后期.在裂陷期的充填序列中,沙一段底界面为整个研究区都可以识别的显著的角度不整合界面,以此界面为界,盆地的裂陷期进一步划分为裂陷Ⅰ幕和裂陷Ⅱ幕.裂陷Ⅰ幕发育了Es3-Es2地层,断裂几何学和断裂的性质表明该幕构造活动为北西南东向伸展作用所致,而裂陷Ⅱ幕发育了Es1-Ed地层,为近南北向拉伸作用的结果.裂后期,从早到晚则表现为由稳定热沉降到加速沉降的过程.分析认为上述盆地的幕式沉降过程与区域应力场的转变密切相关,受控于周缘板块的动力学事件,尤其是晚始新世之后,太平洋板块对欧亚大陆向西的加速俯冲,促使了郯庐断裂右旋活动向南延伸和穿过黄骅坳陷的兰聊断裂北段的活化,形成了位于渤海海域的南北向伸展叠加区,从根本上改变了黄骅坳陷中北区应力场的分布,由此导致了盆地同裂陷阶段的幕式演化. 相似文献
9.
The Glueckstadt Graben, a sedimentary record between the North and Baltic Sea in north Central Europe 总被引：2，自引：1，他引：2
The Glueckstadt Graben is one of the deepest post-Permian structures within the Central European Basin system and is located right at its “heart” at the transition from the North Sea to the Baltic Sea and from the Lower Saxony Basin to the Rynkoebing–Fyn High.The Mesozoic to recent evolution is investigated by use of selected seismic lines, seismic flattening and a 3D structural model. A major tectonic event in the latest Middle–Late Triassic (Keuper) was accompanied by strong salt tectonics within the Glueckstadt Graben. At that time, a rapid subsidence took place within the central part, which provides the “core” of the Glueckstadt Graben. The post-Triassic tectonic evolution of the area does not follow the typical scheme of thermal subsidence. In contrast, it seems that there is a slow progressive activation of salt movements triggered by the initial Triassic event. Starting with the Jurassic, the subsidence centre partitioned into two parts located adjacent to the Triassic “core.” In comparison with other areas of the Central European Basin system, the Glueckstadt Graben was not strongly affected by additional Jurassic and Cretaceous events. During the late Jurassic to Early Cretaceous, the area around the Glueckstadt Graben was affected by relative uplift with regional erosion of the elevated relief. However, subsidence was reactivated and accelerated during the Cenozoic when a strong subsidence centre developed in the North Sea. During Paleogene and Quaternary–Neogene, the two centres of sedimentation moved gradually towards the flanks of the basin.The data indeed point toward a control of post-Permian evolution by gradual withdrawal of salt triggered by the initial exhaustion along the Triassic subsidence centre. In this sense, the Glueckstadt Graben was formed at least partially as “basin scale rim syncline” during post-Permian times. The present day Hamburger, East and Westholstein Troughs are the actual final state of this long-term process which still may continue and may play a role in terms of young processes and, e.g., for coastal protection. 相似文献
10.
The NW–SE-striking Northeast German Basin (NEGB) forms part of the Southern Permian Basin and contains up to 8 km of Permian to Cenozoic deposits. During its polyphase evolution, mobilization of the Zechstein salt layer resulted in a complex structural configuration with thin-skinned deformation in the basin and thick-skinned deformation at the basin margins. We investigated the role of salt as a decoupling horizon between its substratum and its cover during the Mesozoic deformation by integration of 3D structural modelling, backstripping and seismic interpretation. Our results suggest that periods of Mesozoic salt movement correlate temporally with changes of the regional stress field structures. Post-depositional salt mobilisation was weakest in the area of highest initial salt thickness and thickest overburden. This also indicates that regional tectonics is responsible for the initiation of salt movements rather than stratigraphic density inversion.Salt movement mainly took place in post-Muschelkalk times. The onset of salt diapirism with the formation of N–S-oriented rim synclines in Late Triassic was synchronous with the development of the NNE–SSW-striking Rheinsberg Trough due to regional E–W extension. In the Middle and Late Jurassic, uplift affected the northern part of the basin and may have induced south-directed gravity gliding in the salt layer. In the southern part, deposition continued in the Early Cretaceous. However, rotation of salt rim synclines axes to NW–SE as well as accelerated rim syncline subsidence near the NW–SE-striking Gardelegen Fault at the southern basin margin indicates a change from E–W extension to a tectonic regime favoring the activation of NW–SE-oriented structural elements. During the Late Cretaceous–Earliest Cenozoic, diapirism was associated with regional N–S compression and progressed further north and west. The Mesozoic interval was folded with the formation of WNW-trending salt-cored anticlines parallel to inversion structures and to differentially uplifted blocks. Late Cretaceous–Early Cenozoic compression caused partial inversion of older rim synclines and reverse reactivation of some Late Triassic to Jurassic normal faults in the salt cover. Subsequent uplift and erosion affected the pre-Cenozoic layers in the entire basin. In the Cenozoic, a last phase of salt tectonic deformation was associated with regional subsidence of the basin. Diapirism of the maturest pre-Cenozoic salt structures continued with some Cenozoic rim synclines overstepping older structures. The difference between the structural wavelength of the tighter folded Mesozoic interval and the wider Cenozoic structures indicates different tectonic regimes in Late Cretaceous and Cenozoic.We suggest that horizontal strain propagation in the brittle salt cover was accommodated by viscous flow in the decoupling salt layer and thus salt motion passively balanced Late Triassic extension as well as parts of Late Cretaceous–Early Tertiary compression. 相似文献
11.
山东胶莱盆地构造变形及形成演化——以王氏群和大盛群变形分析为例 总被引：12，自引：1，他引：12
胶莱盆地是形成于中生代晚侏罗世的陆相盆地，构造变形较为复杂。在野外断裂构造变形观测的基础上，结合年代学数据和地层沉积序列，确立了胶莱盆地白垩纪的变形演化历史。总体上，胶莱盆地在形成和演化过程中沉积了3套地层，经历了多个构造变形阶段。其中，发生在白垩纪的变形阶段主要有：(1)早白垩世早期，鲁东地区受区域近E—W向引张应力场控制，胶莱盆地发生大规模的火山喷发，喷发间歇期沉积了大盛群；早白垩世晚期，受强烈的区域性NW—SE向挤压，胶莱盆地褶皱回返。(2)晚白垩世早期，在区域近S—N向引张应力作用下，诸城断陷盆地发育，王氏群沉积；晚白垩世晚期，胶莱盆地受区域性NE—SW向挤压，导致王氏群褶皱变形。 相似文献
12.
《Comptes Rendus Geoscience》2014,346(1-2):37-44
We document the sedimentary facies of a large Mass Transport Deposit (MTD) within the sand-rich sediment gravity flow-dominated deposits of the Eocene–Oligocene south-western Alpine forelands (Annot Sandstone system). The MTD with an approximated volume of several hundreds of cubic kilometres fills a sub-basin located in the Mont-Tournairet confined sub-basin. Autochthonous facies are very typical sediment gravity-flow deposits (thin-bedded classical turbidites and thick-bedded hyperconcentrated to concentrated flow deposits) that stratigraphically belong to the Annot Sandstone infill. Slumps and internal metre-large fold axes of the deformed stratigraphic intervals indicate a main transport direction towards the northwest. The seafloor instability that led to the mass-flow events within the Mont-Tournairet sub-basin could have been favoured by high sedimentation rates in a small, confined and tectonically active sub-basin, possibly enhanced by local structural deformation associated with the Triassic evaporites on the eastern side of the Mont-Tournairet confined basin. The presence of the MTD suggests that a period of increased flexural subsidence rate and basin deformation occurred in this portion of the subalpine foreland basin. Therefore, the MTD forms a stratigraphic marker of a period of tectonic activity. 相似文献
13.
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：44，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
14.
构造沉降作为盆地成因研究中的重要组成部分,对其特征进行分析有助于盆地成因的解析。本次通过对鄂尔多斯盆地内5口典型探井的多期不整合所代表的的剥蚀厚度进行恢复,结合去压实矫正模型以及平均密度、平均古水深等参数的确定,较为精确地刻画出了鄂尔多斯盆地不同构造单元自早寒武世至今的构造沉降特征,同时结合裂谷盆地瞬时拉张模型、裂后热坳陷模型以及前陆盆地挠曲模型对构造沉降曲线进行了模拟,对盆地成因进行分析。鄂尔多斯盆地中寒武世—中生代末期主要由早古生代沉降旋回、二叠—三叠纪沉降旋回与侏罗—白垩纪沉降旋回组成。其中岩石圈热冷却作用引起的沉降贯穿全地质时期。早古生代沉降旋回中,中寒武世的加速沉降主要体现在盆地南部,沉降机制为岩石圈伸展减薄,中奥陶世马家期为全盆地尺度的加速沉降,沉降机制仍为岩石圈伸展减薄。二叠—三叠纪沉降旋回中,晚二叠世—早-中三叠世为该旋回的加速沉降期,该期加速沉降具有多幕裂陷的特征。侏罗—白垩纪沉降旋回中,中侏罗世盆地南部处于缓慢沉降期,沉降机制为岩石圈热冷却作用,晚侏罗世—早白垩世,除伊盟隆起,盆地整体处于加速沉降期,沉降机制为前陆盆地引起的挠曲沉降。 相似文献
15.
库车坳陷脆性构造序列及其对构造古应力的指示 总被引：3，自引：0，他引：3
在对野外脆性构造(主要是节理和断层) 大量观测的基础上, 根据它们与应力的关系, 讨论了库车坳陷白垩纪末期以来的古构造应力时空变化.结果表明, 在库车坳陷脆性构造中, 早期隆升作用形成的主要发育在中生界的NEE-SWW向系统节理被晚期同构造期的在中生界与上第三系均发育的NNW-SSE向和NW-SE向节理切割并改造, 这是对区域上构造应力场在进入新近纪时从弱伸展变化到强烈挤压这一过程的响应.基于断层滑动分析的古应力反演结果显示, 此时盆山边界处以近N-S向伸展应力状态占主导, 而坳陷内部则表现为近N-S向和NW-SE向挤压应力状态.说明在进入新近纪后, 最大主应力(σ1) 方向从垂向变成水平, 应力场发生了转变.此后的天山快速垂向隆升是库车坳陷北缘和内部应力状态存在差异的原因. 相似文献
16.
库车坳陷东部具有丰富的油气资源,其构造变形机制与南天山造山带密切相关。综合采用露头共轭节理及白垩系残余厚度分布,分析了库车坳陷东部晚白垩世古隆起特征及构造应力场属性。吐格尔明、克孜勒努尔沟、库车河、卡普沙良河、吉迪克以及库车河西6条剖面的共轭节理分析表明,库车坳陷东部新生代构造挤压应力为NNW-SSE向,而中生代的构造挤压应力为NE-SW向。原型盆地恢复显示,库车坳陷白垩纪的沉积中心大致位于大北1井―吐北2井―克拉2井一线,且发育秋里塔格―新和―牙哈―提尔根古隆起带,白垩系原始沉积厚度总体上北厚南薄。在晚白垩世区域抬升剥蚀的构造背景下,坳陷东部受压隆升遭受剥蚀,白垩系残余厚度减薄,呈西厚东薄的趋势。位于坳陷东部的吐格尔明背斜在石炭纪―三叠纪为一个长期存在的继承性沉积古隆起,晚白垩世进一步隆升形成构造古隆起,背斜周缘的白垩系残余厚度进一步减薄。吐格尔明背斜和背斜周缘白垩系残余厚度等值线以及库北1井和库车河剖面周缘白垩系残余厚度等值线的长轴方向均为NW-SE向,进一步证实了库车坳陷东部晚白垩世的构造应力为NE-SW向。库车坳陷东部晚白垩世古隆起与构造应力场属性主要与特提斯造山带中地体增生和拼贴作用导致的特提斯北缘盆地群中发生的区域性抬升有关。 相似文献
17.
柴达木盆地新生代沉积转移及其动力学意义 总被引：8，自引：1，他引：7
新生代柴达木盆地的坳陷、沉积作用和周缘山体隆升存在着很好的耦合关系,沉积中心位置、沉积范围大小及沉积中心的平面形态有规律的变化,反映出新生代柴达木盆地承受过来自北缘祁连山方向、西北缘阿尔金山方向以及南缘昆仑山方向三组挤压应力的作用,其中来自阿尔金山方向的应力一直在持续发挥作用;来自盆地南北缘的应力也始终发挥重要作用,同时经历了一个由北东向(古近纪早—中期)→北北东向(古近纪末期—中新世早期)→近南北向(中新世中期—上新世中期)→北东向(上新世晚期)的转向过程。在此基础上建立了柴达木盆地新生代发展演化模式,提出柴达木盆地新生代经历了由北向南挤压—旋转、由南西向北东挤压—旋转以及由向北挤压—旋转的动力学演化过程。 相似文献
18.
The Xining Basin is located in the northeastern Qinghai–Tibetan Plateau, and its continuous Cenozoic strata record the entire uplift and outgrowth history of the Tibetan Plateau during the Cenozoic. The newly obtained apatite fission track data presented here shows that the Xining Basin and two marginal mountain ranges have experienced multiphase rapid cooling since the Jurassic, as follows. In the Middle–Late Jurassic, the rapid exhumation of the former Xining Basin resulted from collision between the Qiangtang Block and the Tarim Block. During the Early–Late Cretaceous, the former Xining Basin underwent a tectonic event due to marginal compression, causing the angular unconformity between the Upper and Lower Cretaceous. In the Late Cretaceous to the Early Cenozoic, collision between the Qiangtang Block and the Lhasa Block may have resulted in the rapid exhumation of the Xining Basin and the Lajishan to the south. In the Early Cenozoic(ca. 50–30 Ma), collision between the Indian and Eurasia plates affected the region that corresponds to the present northeastern Qinghai–Tibetan Plateau. During this period, the central Qilian Block rotated clockwise by approximately 24° to form a wedge-shaped basin(i.e., the Xining Basin) opening to the west. During ca. 17–8 Ma, the entire northeastern Qinghai–Tibetan Plateau underwent dramatic deformation, and the Lajishan uplifted rapidly owing to the northward compression of the Guide Basin from the south. A marked change in subsidence occurred in the Xining Basin during this period, when the basin was tectonically inverted. 相似文献
19.
The study provides a regional seismic interpretation and mapping of the Mesozoic and Cenozoic succession of the Lusitanian Basin and the shelf and slope area off Portugal. The seismic study is compared with previous studies of the Lusitanian Basin. From the Late Triassic to the Cretaceous the study area experienced four rift phases and intermittent periods of tectonic quiescence. The Triassic rifting was concentrated in the central part of the Lusitanian Basin and in the southernmost part of the study area, both as symmetrical grabens and half-grabens. The evolution of half-grabens was particularly prominent in the south. The Triassic fault-controlled subsidence ceased during the latest Late Triassic and was succeeded by regional subsidence during the early Early Jurassic (Hettangian) when deposition of evaporites took place. A second rift phase was initiated in the Early Jurassic, most likely during the Sinemurian–Pliensbachian. This resulted in minor salt movements along the most prominent faults. The second phase was concentrated to the area south of the Nazare Fault Zone and resulted here in the accumulation of a thick Sinemurian–Callovian succession. Following a major hiatus, probably as a result of the opening of the Central Atlantic, resumed deposition occurred during the Late Jurassic. Evidence for Late Jurassic fault-controlled subsidence is widespread over the whole basin. The pattern of Late Jurassic subsidence appears to change across the Nazare Fault Zone. North of the Nazare Fault, fault-controlled subsidence occurred mainly along NNW–SSE-trending faults and to the south of this fault zone a NNE–SSW fault pattern seems to dominate. The Oxfordian rift phase is testified in onlapping of the Oxfordian succession on salt pillows which formed in association with fault activity. The fourth and final rift phase was in the latest Late Jurassic or earliest Early Cretaceous. The Jurassic extensional tectonism resulted in triggering of salt movement and the development of salt structures along fault zones. However, only salt pillow development can be demonstrated. The extensional tectonics ceased during the Early Cretaceous. During most of the Cretaceous, regional subsidence occurred, resulting in the deposition of a uniform Lower and Upper Cretaceous succession. Marked inversion of former normal faults, particularly along NE–SW-trending faults, and development of salt diapirs occurred during the Middle Miocene, probably followed by tectonic pulses during the Late Miocene to present. The inversion was most prominent in the central and southern parts of the study area. In between these two areas affected by structural inversion, fault-controlled subsidence resulted in the formation of the Cenozoic Lower Tagus Basin. Northwest of the Nazare Fault Zone the effect of the compressional tectonic regime quickly dies out and extensional tectonic environment seems to have prevailed. The Miocene compressional stress was mainly oriented NW–SE shifting to more N–S in the southern part. 相似文献
20.
沁水盆地南缘自中生代以来,主要经历了印支期、燕山期、喜马拉雅期三期构造活动的影响。通过对地表露头的断 层面擦痕、纵弯褶皱及共轭节理系的研究,获得了古构造应力场信息。在研究区东部 NNE 向的太行山断裂带内,逆冲挤压 构造非常明显,与其相伴发育的不对称背斜构造表明其主压应力方向为 110°;中部的 EW 向正断层、地堑系可能是印支期 近 SN 向挤压作用下形成的逆冲构造经历了新生代构造反转作用而产生的,新生代伸展作用非常显著,伸展方向为 26°, 249°,347°;西部边界由近 SN 向断裂组成,存在新生代近 EW 及 NEE-SSW 向伸展运动的擦痕证据,伸展方向为 94°,72°。 区内发育 NNW-SSE,NW-SE,NE-SW,NEE-SWW,近 SN 等几个方向的共轭节理系,表明存在过燕山期 NW-SE 向的水平 挤压构造应力场和喜山期 NE-SW 向水平挤压构造应力场,近 EW 向水平挤压应力场可能是在这两期主要构造应力场转换过 程中形成的。 相似文献