桂中坳陷改造期构造样式及其成因

桂中坳陷的构造演化一般划分为原型期和改造期两大阶段。改造期主要属于挤压构造样式,目前的研究还相对比较薄弱。从大地构造动力学背景入手,结合区域地质事件,按照盆地发育世代与造山带演化阶段,综合近期野外地质调查与深层地球物理勘探成果等,分析了改造期挤压构造样式。主要有三大区域性冲褶变形构造系,包括大瑶山逆冲推覆构造系,右江逆冲推覆构造系以及雪峰山隆起南缘重力滑覆构造系。总体上,负向地形多褶皱紧闭,正向地形形成相对宽缓的箱状复式背斜褶皱;深层主要发育有基底断裂卷入引发的冲起构造以及与断层相关的断弯、断展、滑动等褶皱样式,浅层有逆冲推覆、纵弯、叠加等褶皱样式。目前桂中坳陷受到东西两侧剪切、向南拉张的应力作用。     

从地震信息看红河—金沙江断裂带构造特征

红河—金沙江断裂带,根据地质结构的差异可分为北段羌塘向北叠瓦逆冲断裂带,中段三江—哀牢山向东叠瓦逆冲断裂带,南段河内—中建正反转走滑断裂带。北段和中段均由三组基本平行的叠瓦逆冲断层构成,显示以强烈挤压为特征,但后者相对较弱;南段则经历了古近纪由挤压反转为拉张,形成一些断陷构造,新近纪又反转为挤压,断陷转变为坳陷,形成河内、莺歌海及中建等坳陷。该南段的主断层为正反转构造逆冲带的前锋太平断裂带,与原先人们所认为的不相同。红河—金沙江断裂带的挤压特征总体上由北往南逐渐减弱,其演化受特提斯构造活动所控制。断裂带的油气勘探成果表明,在喜马拉雅期形成的断坳结构盆地中油气显示较好。     

库车坳陷第三纪断层滑动分析与古构造应力恢复

研究构造应力场的时空变化对于认识和理解褶皱冲断带的构造变形过程和油气构造圈闭的最终定型具有重要意义.基于对库车坳陷内第三系和同时卷入变形的白垩系中发育断层的野外观测,采用断层滑动数据反演方法,对库车坳陷的第三纪构造古应力进行恢复.结果表明:库车坳陷第三纪的构造应力方向在空间位置上变化不大,在时间上经历了从NNW-SSE向到NWW-SEE的转变,构造挤压变形经历了两个阶段:即NNW-SSE向逆冲挤压变形和相对较晚的NWW-SEE向逆冲挤压变形.结合库车坳陷油气成藏期,第二阶段的构造挤压变形发生在库车组沉积期间,为坳陷内油气的聚集提供了良好的圈闭条件.文中还探讨了造成库车坳陷内挤压应力场的两种可能动力成因.     

从地震信息看中国东部和中国中西部沉积盆地构造演化动力学与断块油气藏(下) 中国中西部盆地演化及断块(圈闭)油气藏

中国中西部地区以塔里木盆地及其演化为典型代表。震旦纪以来,经历了地台发育、持续沉降、拉张翘倾、挤压坳陷及断陷推覆等构造发育阶段,与中国东部一样,表现为拉张与挤压交互出现的手风琴式演化史,突出的差别在于晚喜马拉雅期在西部地区形成强烈的挤压逆掩推覆构造,而东部地区只形成坳陷式的沉积盆地。中亚—蒙古大洋、秦—祁—昆大洋、古特提斯洋、中特提斯洋、印度洋以及印度板块等在不同地质时期的板块活动是中国中西部地区盆地演化发展的动力学因素。根据地震剖面解释成果,可确定出四种断块油气藏类型,均反映后期挤压逆冲特征,尤其是燕山期—喜马拉雅期推覆前锋带断块油气藏,还可区分为拆离型、褶皱型、前冲型和反冲型等四种,且每一种还可再区分出若干种。     

临清坳陷东部中,新生代构造演化特征

临清坳陷东部是一个中，新生代断陷。早三叠世该区为一台坳，晚三叠世褶皱抬升，侏罗纪一早白垩世为ＮＷ走向的拉分盆地，晚白垩世的左旋挤压其再次褶皱，抬升。早第三纪的裂陷作用使其拉张伸展，断块通过水平伸展。差异升降和掀斜运动形成了伸展构造系统，使坳陷最终形成两凹一凸的构造格局和５种结构形式，晚第三纪以后，该区则以整体拗陷为特征。该区中，新生代的构造演化可划分为４个旋回或阶段，即三叠纪的台拗旋回，侏罗－白垩     

北黄海盆地东部坳陷中新生代构造样式

北黄海盆地东部坳陷中新生代自下而上发育中侏罗统、上侏罗统、下白垩统、渐新统和新近系,划分为3个构造层,即下构造层、中构造层和上构造层,分别对应盆地的中生代断陷-反转阶段、古近纪断陷—反转阶段和区域沉降阶段3期构造演化阶段。不同的构造演化阶段造就了不同的构造样式,基于地震反射资料,结合盆地地质结构特征,总结了坳陷构造样式特征,即伸展构造、挤压构造、反转构造及扭动构造4种样式,以伸展构造样式为主,翘倾断块、滑动断阶及逆牵引背斜是研究区内有利于油气运聚成藏的主要构造样式。     

中国含油气盆地的反转构造样式及其油气聚集

反转构造主要指伸展盆地中地堑、半地堑系统遭受挤压变形所产生的压缩构造。它一般经历拉张断陷、稳定坳陷及挤压反转三个演化阶段,构造反转形成的各种褶皱背斜构造直接叠覆在生油断陷之上,生运储配置关系得天独厚,有利于油气聚集。对我国油气勘探反转构造进行成因分类,归纳出断层型、走滑型、热力型及重力型四大类,每一类又可识别出若干种。如断层型反转褶皱,根据张性断层与压性断层的相互叠加关系,可以识别出六种:断层扩展反转褶皱,断层弯曲反转褶皱,断层滑脱反转褶皱,截断型反转褶皱,滑脱逆掩断坡型反转构造,褶皱型反转构造。其中又以断层扩展、断层弯曲、滑脱逆掩断坡和褶皱型等反转构造的含油气性最好。     

中国中西部盆地演化及断块（圈闭）油气藏

中国中西部地区以塔里木盆地及其演化为典型代表,震旦纪以来,经历了地台发育,持续沉降,拉线翘倾,挤压坳陷及断陷推覆等构造发育阶段,与中国东部一样,表现为拉张与挤太交互出现的手风琴式演化史,突出的差别在于晚喜马拉雅期在西部地区形成强烈的挤压逆掩推覆构造,而东部地区只形成坳陷式的沉积盆地,中亚－蒙古大洋,秦－祁－昆大洋,古特提斯洋,中特提斯洋,印度洋以及印度板块等在不同地质时期的板块活动是中国中西部地区     

大杨树盆地的构造特征及变形期次

大杨树盆地是叠置于大兴安岭造山带的东部,与松辽盆地紧邻,呈北北东向长条带状展布的中新生代断陷-坳陷型盆地。大杨树盆地经历了多期变形作用,具有以伸展构造为主、并被挤压构造和反转构造叠加的构造特征。早白垩世龙江期主要受到了NWW—SEE向的拉伸作用,形成一系列北北东向控陷犁式正断层组合,在控陷断层的上盘发育小型箕状断陷;早白垩世九峰山期,大杨树盆地受挤压作用控制,使早期形成的断陷盆地发生反转作用,形成正反转构造,同时在某些地段形成逆冲断层和断层传播褶皱;早白垩世甘河期,大杨树盆地再次受到伸展作用,形成了一系列北北东向小型断陷。早白垩世晚期(甘河期之后)—晚白垩世早期,大杨树盆地受到强烈的挤压作用,使早期控陷正断层出现正反转作用,在盆地的浅部形成大型断层传播褶皱,使大杨树盆地全面隆升遭受剥蚀。第四纪大杨树盆地具有伸展的特征,发育一系列小型伸展断陷。     

济阳坳陷不同区带构造样式发育与油气富集差异性分析

构造样式控制沉积并决定油气富集。通过对济阳坳陷盆地结构特征、构造演化、地震资料及不同区带油气地质模型的分析,认为该坳陷构造样式主要有翘倾断块、滑动断阶、潜山披覆、重力构造、底辟构造等7种类型,不同构造带是由断陷期发育的不同类型的构造样式叠置组合而成:陡坡带是由早期板式断层被晚期滑动断阶、逆牵引背斜改造而成,中央隆起带是由晚期的背斜、半背斜叠加在早期洼陷之上而成,缓坡带是由早期和晚期不同类型翘倾断块叠置而成,凸起带是在潜山背斜背景上发育起来的披覆构造;不同区带构造样式发育的差异,控制了油气富集的差异,凸起带、底辟背斜的中央隆起带及主控断层演化程度高的陡坡带油气富集。     

新近纪以来中国构造演化特征与天然气田的分布格局

中国地处三大板块间的三角地带 ,是世界上新近纪以来构造运动活跃地区之一 ,与油气成藏及保存条件相关的主要特征是 :(1)在西部 ,古老造山带的重新活跃 ,在其前缘形成前陆盆地及逆冲构造 ,新近纪以来的急剧沉降、快速沉积 ,促进了深部源岩有机质的演化进程 ,也为生物气藏的形成创造了有利的地质条件 ;(2 )多期次的构造热事件及高热流值促进了有机质的快速演化、成藏 ,以及异常高压及泥拱等特殊构造的形成 ;(3)多期次构造运动为油气的快速运聚、幕式充注成藏提供了优质输导系统 ,为超晚期快速成藏提供了储聚场所 ;(4 )大断裂、岩浆及深部热流体的活动 ,不仅促进有机成因油气藏的形成 ,也是无机成因气的主要释放和聚集时期。新近纪以来构造演化特征在西部影响最广泛 ,也最深刻 ,形成的前陆盆地是中国重要天然气聚集区之一 ,是这些盆地本部气藏最终形成、定型时期 ,并在造山带内形成了近百个小型断陷盆地 ,形成了新的油气勘探领域。在中部 ,是四川盆地所有气田最终的形成、定型时期 ;在鄂尔多斯盆地促进了靖边至乌审旗地区天然气进一步富集。在东部 ,渤海海域形成一批大中型油气田 ,促进了其他盆地 (坳陷 )不同成因气藏的形成 ;在近海海域 ,既促进了有机成因气藏快速形成 ,也促进了无机成因非烃气藏以及无?     

Polyphase Tectonic Events and Cenozoic Basin-Range Coupling in the Tianshan Belt, Northwestern China

Studies show that the Tianshan orogenic belt was built in the late stage of the Paleozoic, as evidenced by the Permian red molasses and foreland basins, which are distributed in parallel with the Tianshan belt, indicating that an intense folding and uplifting event took place. During the Triassic, this orogenic belt was strongly eroded, and basins were further developed. Starting from the Jurassic, a within-plate regional extension occurred, forming a series of Jurassic-Paleogene extensional basins in the peneplaned Tianshan region. Since the Neogene, a collision event between the Indian and the Eurasian plates that took place on the southern side of the Tianshan belt has caused a strong intra-continental orogeny, which is characterized by thrusting and folding. Extremely thick coarse conglomerate and sandy conglomerate of the Xiyu Formation of Neogene System were accumulated unconformably on the Tianshan piedmont. Studies have revealed that the strong compression caused by the Indian-Eurasian collision     

Déformations néogènes et quaternaires de la bordure nord haut atlasique (Maroc): rôle du socle et consequences structurales

According to major discontinuities, continental deposits in the Cenozoic Atlas basins are subdivided into three groups (pre-, syn- and post-tectonic). Progressive unconformities are the main characteristic of the syntectonic formations, implying that the Atlas tectonic episode is synchronous with Neogene and Quaternary sedimentation. This tectonic episode is responsible for the inversion of Early Mesozoic extensional structures within the basement, which were reactivated into symmetrical thrusts or transpressional faults. Shortening of the basement induced the detachment of the cover. Deformation of the cover is expressed by thrust faults (with southern and northern vergences), folds and flexures linked to blind thrusts. Kinematic data show that the main regional compression was directed N150 ± 10° during the Neogene and north-south during the Quaternary. The involvement of the upper crust, in the Alpine Atlasic Belt, contributed to create areas of high relief. The High Atlas can be interpreted as resulting from large Cenozoic thrusts, and compared with the Pyrenean Axial Zone, although their pre-Cenozoic histories can differ markedly.     

Styles of tectonic inversion within syn-orogenic basins: examples from the Central Apennines, Italy

The geometry of several thrust-related folds in the Central Apennines of Italy results from a switch in deformation regime, from extension to contraction. This switch in tectonic regime occurred during the deposition of syn-orogenic sediments, and the emplacement and migration of the thrust belt–foredeep system towards the foreland in Neogene time. The styles of positive tectonic inversion result from normal faults that were steepened, rotated and truncated by thrusts, with local development of minor folds due to buttressing. Normal fault-controlled escarpments are also locally preserved in the forelimbs and backlimbs of thrust-related anticlines. The location and amplitudes of contractional structures across the belt reflects the distribution of pre-thrusting normal faults within precursor syn-orogenic basins, a result that may improve our understanding of the evolution of Apennine, as well as other thrust belt–foredeep systems.     

Structural development of the Neogene Radicondoli–Volterra and adjoining hinterland basins in Western Tuscany (Northern Apennines,Italy)

This paper presents a geological–structural study of some Neogene hinterland basins of the Northern Apennines, located on the Tyrrhenian side of the chain. These basins developed on the already delineated thrust-fold belt from middle–late Tortonian times. Their evolution has been commonly referred to an extensional tectonic regime, related to the opening of the Tyrrhenian Sea. New data have allowed us to hypothesize a different tectonic evolution for the chain, where compressive tectonics plays a major role both in the external and in the hinterland area. In this frame, the hinterland area located west of a major outcropping crustal thrust (Mid-Tuscany Metamorphic Ridge) has been the target of a geological–structural investigation. The field mapping and structural analysis has been focused on the syntectonic sediments of the Radicondoli–Volterra basin as well as on adjoining minor basins. These basins commonly display a synclinal structure and are generally located in between basement culminations, probably corresponding to thrust anticlines. Sediments of the hinterland basins have been affected by compressive deformation and regional unconformities separate stratigraphic units due to the activity of basement thrusts. In the study area, normal faulting either accommodates the thrusting processes or post-dates compressive deformation. A chronology of faulting and a six-stage evolution of this area are presented, providing further insights for the Neogene tectonic evolution of the Northern Apennines. Copyright © 1998 John Wiley & Sons, Ltd.     

Tertiary to recent oblique convergence and wrenching of the Central Dinarides: Constraints from a palaeostress study

The late Eocene to Neogene tectonic evolution of the Dinarides is characterised by shortening and orogen-parallel wrenching superposed on the late Cretaceous and Eocene double-vergent orogenic system. The Central Dinarides exposes NW-trending tectonic units, which were transported towards the Adria/Apulian microcontinent during late Cretaceous–Palaeogene times. These units were also affected by subsequent processes of late Palaeogene to Neogene shortening, Neogene extension and subsidence of intramontane sedimentary basins and Pliocene–Quaternary surface uplift and denudation. The intramontane basins likely relate to formation of the Pannonian basin. Major dextral SE-trending strike-slip faults are mostly parallel to boundaries of major tectonic units and suggest dextral orogen-parallel wrenching of the whole Central Dinarides during the Neogene indentation of the Apulian microplate into the Alps and back-arc type extension in the Pannonian basin. These fault systems have been evaluated with the standard palaeostress techniques. We report four palaeostress tensor groups, which are tentatively ordered in a succession from oldest to youngest: (1) Palaeostress tensor group 1 (D₁) of likely late Eocene age indicates E–W shortening accommodated by reverse and strike-slip faults. (2) Palaeostress tensor group 2 (D₂) comprises N/NW-trending dextral and W/WSW-trending sinistral strike-slip faults, as well as WNW-striking reverse faults. These indicate NE–SW contraction and subordinate NW–SE extension related to Oligocene to early Miocene shortening of the Dinaric orogenic wedge. (3) Palaeostress tensor group 3a (D_3a) comprises mainly NW-trending normal faults, which indicate early/middle Miocene NE–SW extension related to syn-rift extension in the Pannonian basin. The subsequent palaeostress tensor group 3b (D_3b) includes NE-trending, SE-dipping normal faults indicating NW–SE extension, which is likely related to further extension in the Pannonian basin. (4) Palaeostress tensor group 4 (D₄) is characterised by mainly NW-trending dextral and NE-trending sinistral strike-slip faults. Together, with some E-trending reverse faults, they indicate roughly N–S shortening and dextral wrenching during late Miocene to Quaternary. This is partly consistent with the present-day kinematics, with motion of the Adriatic microplate constrained by GPS data and earthquake focal mechanisms. The north–north-westward motion and counterclockwise rotation of the Adriatic microplate significantly contribute the shortening and present-day wrenching in the Central Dinarides.     

Tectonic Characteristics and Evolution of the Taiwan Strait

The Taiwan Strait is a part of the continental-margin rift of eastern China, which can tectonically be divided into the Taiwan Strait basin, southwestern Taiwan basin and Penhu-Beigang uplift. The basins are structurally semi-graban down-faulted ones in character. The Cretaceous-Cenozoic sedimentary strata in the basins have a maximum thickness of over 10,000 m. The formation and development of the Taiwan Strait rift were not only affected by both the East China Sea basin and South China Sea basin but also closely related to the Central Range collision orogen of Taiwan. In the Cenozoic, the Taiwan Strait area experienced, under the influence of a multiple of tectonic mechanisms, three stages of evolution: poly-centre downfault-ing, down warping-faulting and foreland basin formation. The depositional centres of the basins migrated from west to east during the Tertiary, resulting in the thinning of the Palaeogene strata from west to east but that of the Neogene in the reverse direction. All this determine     

秘鲁三个前陆盆地油气地质条件对比

Maranon、Ucayali和Madre de Dios盆地是3个弧后前陆盆地,对比研究发现：(1)古近纪和新近纪的构造运动对Ucayali盆地的影响比Maranon盆地要大。Maranon盆地西边界的古生代地层被大断层裂开,除了在老构造上有低幅度褶皱外并未明显被反转或压缩;而在Ucayali盆地内,则发育基底相关的逆冲褶皱和反转构造。(2)三叠纪期间,Maranon和Ucayali盆地的大部分地区,大的断裂和构造抬升交替保存和剥蚀着原古生代的地层,而在Madre de Dios盆地,很少有断层产生或抬升剥蚀,导致Madre de Dios盆地古生代地层比Maranon和Ucayali盆地保存较好。(3)自北向南3个盆地的主力烃源岩和主力储层的地层年代越来越老。盆地的前渊带,储层埋藏深度大和成岩作用强的特点导致储层的物性明显变差。(4)晚白垩世以来的挤压和冲断运动在3个盆地的中西部形成了大量中-高幅度的背斜、断背斜等构造圈闭。盆地东部的地层向克拉通地台方向逐层超覆,发育地层圈闭。Maranon和Ucayali盆地北部, 新近纪的构造挤压运动影响到基底,使断层贯穿至盆地基底,发育与基底相关的断层,而在Ucayali盆地的最南部发育薄皮式断层。最后,指出了3个盆地下一步勘探的领域和方向。     

中国东部某些中、新生代含油气盆地与部分北东向正断层成因分析

中国东部中、新生代含油气盆地众多,为断陷盆地类型,断层发育也往往表现为正断层形式。对这些盆地性质、形成机制以及正断层的力学性质的认识众说纷纭,但以张、张扭性盆地和张、张扭性断层之说占主导。本文从大地构造体系环境、构造型式特点、区域与局部应力场分析、定向岩心破裂面观察、地震反射信息,晚近时期构造形迹(如天然地震裂隙、断裂)组合规律的地质分析以及正断层控油特点等方面,对盆地及控盆断层性质进行了分析研究,认为中国东部某些断陷盆地、NE向控盆正断层和盆内主干NE向正断层为扭性或压扭性,其形成缘于构造应力与重力联合作用的结果。