江南东段地区NE-SW向断裂带断层滑移矢量反演及其大地构造意义

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.     

Successive Extensional Tectonic Regimes during the Mesozoic as Evidenced by Neptunian Dikes in the Pontide Magmatic Arc,Northeast Turkey

The eastern Pontide magmatic arc extends ～600 km in an E-W direction along the Black Sea coast and was disrupted by a series of fault systems trending NE-SW, NW-SE, E-W, and N-S. These fault systems are responsible for the formation of diachronous extensional basins, rift or pull-apart, in the northern, southern, and axial zones of the eastern Pontides during the Mesozoic. Successive extensional or transtensional tectonic regimes caused the abortive Liassic rift basins and the Albian and Campanian pull-apart basins with deep-spreading troughs in the southern and axial zones. Liassic, Albian, and Campanian neptunian dikes, which indicate extensional tectonic regimes, crop out within the Paleozoic granites near Kale, Gumushane, and the Malm–Lower Cretaceous platform carbonates in Amasya and Gumushane. These neptunian dikes correspond to extensional cracks that are filled and overlain by the fossiliferous red pelagic limestones. Multidirectional Liassic neptunian dikes are consistent with the general trend of the paleofaults (NE-SW, NW-SE, and E-W), and active dextral North Anatolian fault (NAF) and sinistral Northeast Anatolian fault (NEAF) systems. The Albian neptunian dikes in Amasya formed in the synthetic oblique left-lateral normal faults of the main fault zone that runs parallel to the active North Anatolian fault zone (NAFZ).

Kinematic interpretation of the Liassic and Albian neptunian dikes suggests N-S extensional stress or northward movement of the Pontides along the conjugate fracture zones parallel to the NAFZ and NEAFZ. This northward movement of the Pontides in Liassic and Albian times requires left-lateral and right-lateral slips along the conjugate NAFZ and Northeast Anatolian fault zones (NEAFZ), respectively, in contrast to the recent active tectonics that have been accommodated by N-S compressional stress. On the other hand, mutual relationships between the neptunian dikes and the associated main fault zone of Campanian age extending in an E-W direction in the Kale area, Gumushane suggest the existence of a main left-lateral transtensional wrench zone. This system might be accommodated by the counterclockwise convergence of the Turkish plate with the Afro-Arabian plate relative to the Eurasian plate, and the southward oblique subduction of Paleotethys beneath the eastern Pontide magmatic arc during the Mesozoic.     

郯庐断裂带(安徽段)及邻区的动力学分析与区域构造演化

依据区域构造层次划分,采用构造筛分法,层层深入,层层筛分,确定发生于各个不同时代地层/岩层内的断裂活动的同期及叠加的应力场特征。综合所有的同期应力场特征及辅以叠加的应力场特征来验证,从而确定了一个连续的、完整的断裂活动的应力场演化序列;结合区域构造变形特征分析,阐明郯庐断裂带(安徽段)的构造演化。应力场分析显示:晚三叠-早侏罗世应力场为北北西—南南东或近南北向挤压,属古特提斯构造域,断裂发生同造山走滑;早白垩世早期,应力场为北西—南东向挤压,断裂发生左行走滑运动,中国东部处于西环太平洋构造域;早白垩世晚期—古新世(始新世),区域发生北西—南东向伸展作用,断裂处于伸展断陷作用阶段;新生代,受区域上近东西向的挤压作用影响,断裂发生挤压逆冲兼右行走滑作用。     

川滇西部上新世以来构造地貌:断裂控制的盆地发育及对于远程陆内构造过程的约束

青藏高原隆升、周边地貌形成是新生代时期印度-欧亚板块碰撞后的重要响应。在滇西北地区发育了一系列由晚新生代(上新世以来)活动断裂所控制的盆地,例如宾川盆地、洱海盆地、鹤庆盆地、弥渡盆地等。宾川盆地是近南北向程海左行走滑断裂在走滑剪切作用下产生的北西向正断层和北东向走滑断层共同作用而形成的一个较大的拉分盆地。洱海盆地是由两组陡立的共轭张剪性(Transtensional)断层组限定的,为一伸展断陷盆地,总体上反映了近E-W向的区域伸展。滇西北地区发育的其它晚新生代盆地,如弥渡盆地、鹤庆盆地、剑川盆地等,也为区域走滑断裂及其分支断裂所控制,并且这些分支断裂在区域上为一组NE-SW和NW-SE向的共轭正断裂,反映了该区域近E-W向的伸展。将藏东南三江地区发育的活动断裂按照其走向分为三组:(1)NW-SE走向的断裂,如红河断裂、无量山-营盘山断裂等;(2)近N-S向断裂系,以程海断裂、小江断裂等为代表;(3)NE-SW走向的断裂,如丽江-剑川断裂、鹤庆-洱源断裂和南定河断裂等。这些断裂的震源机制解表明地震断裂活动性或者是走滑性质或者是伸展属性,它们的组合型式也揭示出藏东南三江地区在上新世以来表现为近E-W向的伸展。区域上,在藏东北部地区发育的断层构造组合普遍反映了以近E-W向挤压为主导的应力场。推测这一现象为上新世以来藏东地区上地壳围绕喜马拉雅东构造结做顺时针旋转所致,区域上受印度-欧亚会聚过程中印度板块顺时针旋转诱发的差异性应力场制约。     

华南中生代大地构造研究新进展

华南地区中生代构造动力体制经历了从特提斯构造域向滨太平洋构造域的转换,由此产生了强烈的陆内造山作用和岩浆活动,形成了复杂构造组合的晚中生代陆内造山带和火成岩省。本项研究在下列几个方面取得了新的进展:(1)通过对雪峰山地区沅麻盆地的野外调查和构造测量,确定了该盆地晚中生代-早新生代5期构造应力场及其演替序列:中晚侏罗世近W—E向挤压、早白垩世NW—SE向伸展、早白垩世中晚期NW—SE向挤压、晚白垩世近N—S向伸展、古近纪晚期NE—SW向挤压。构造应力场方向的变化记录了不同板缘的动力作用对该区的影响。(2)识别了湖南地区晚古生代-早中生代海相地层中发育的横跨叠加褶皱构造,并基于地层接触关系和已有火成岩同位素年代学数据分析,认为该地区横跨叠加褶皱构造记录了中生代两期构造挤压和地壳增厚事件:早期近东西向褶皱构造是对三叠纪华南地块南北边缘大陆碰撞和增生作用的远程响应,晚期NE—NNE向褶皱构造则是对中晚侏罗世古太平洋板块向华南大陆之下低角度俯冲作用的变形响应。(3)对湖南衡山西缘拆离断裂带的变形结构和运动学特征进行了详细的调查和构造测量,确定了衡山变质核杂岩构造,并对拆离带中韧性剪切变形的钠长岩脉的锆石进行了SHRIMP U-Pb测年,从而确定了华南地区伸展构造的起始时代约137 Ma,即早白垩世早中期。(4)通过锆石U-Pb年代学测试分析,揭示了东南沿海长乐—南澳构造带早白垩世2期构造-岩浆事件:早期(147~135 Ma)表现为强烈的混合岩化作用和深熔作用形成的片麻状花岗岩、花岗片麻岩等;晚期(135~117 Ma)岩浆岩以含石榴子石花岗岩为主。这个结果表明东南沿海构造带是晚中生代陆缘造山带,造山作用可能起始于晚侏罗世,于早白垩世早中期(135 Ma)以来发生伸展垮塌。在上述研究结果的基础上,探讨了华南地区三叠纪"印支运动"和中、晚侏罗世"燕山运动"的表现及其产生的板块构造动力体制及其转换时代、早白垩世从挤压构造应力体制向伸展构造应力体制转变的时间节点。     

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

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。     

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

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。     

六盘山盆地形成和改造历史及构造应力场演化

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。     

The northern New Hebrides back-arc troughs: history and relation with the North Fiji basin

The New Hebrides back-arc troughs (southwest Pacific) are located between the New Hebrides trench-arc system and the active North Fiji marginal basin. They are restricted to the southern and northern segments of the arc and were generally related to effects of the Indo-Australian subducting plate (rolling-back and/or subduction of the d'Entrecasteaux ridge). A detailed bathymetric and magnetic survey over the northern back-arc troughs is used to propose a new model for the origin of the New Hebrides back-arc troughs. The northern troughs extend over a width of 60 km and are composed of N-S trending grabens and horsts, discontinuous along strike and associated with volcanism. The troughs are disrupted southward at 13° 30′S, where the Hazel Holme fracture zone intercepts the New Hebrides island arc. The E-W trending Hazel Holme fracture zone is an extensional feature bisecting the North Fiji basin. In its western end, the Hazel Hohne fracture zone is composed of a succession of horsts and grabens striking N90 ° –N100 ° E. Geometrical and structural relationships between the back-arc troughs and the Hazel Holme fracture zone suggest that both these extensional features result from the same process and are closely linked. The northern troughs-western end of the Hazel Holme fracture zone region is dominated by N130°–135°E trending magnetic lineations typical of oceanic crust. These lineations are oblique to the horsts and grabens systems, and are characteristic of the old North Fiji basin oceanic crust. Consequently we conclude that the northern back-arc troughs are partly developed on the North Fiji basin oceanic basement and that extensional tectonic processes postdate the oldest North Fiji basin oceanic crust. Morphological and structural evidence suggests that both the back-arc troughs and the Hazel Holme fracture zone are recent, still active and result from NE-SW extensional tectonics. Because other tectonic features throughout the North Fiji basin are related to the same stress field, it is inferred that such a NE-SW extension could be a large-scale deformation affecting the North Fiji basin. It is proposed that the back-arc troughs are primarily related to this recent extension within the North Fiji basin, but their locations along the arc are also influenced by the subduction of the d'Entrecasteaux ridge which produces, south of 13°30′S, nearly E-W trending compression and prevents the formation of troughs. Possibly, these recent extensional tectonic processes result from a major reorganization in the spreading process of the North Fiji basin, and could be as young as 0.6–0.7 Ma.     

天水盆地晚新生代构造演化——对青藏高原北东向扩展的指示意义

天水盆地是一个位于青藏高原东北缘的晚新生代盆地,西秦岭北缘断裂穿盆而过。盆地内充填了较为完整的晚新生代地层,记录了该区晚新生代以来的构造变形历史,对研究青藏高原北东向扩展的构造响应具有重要意义。本文基于详细的野外构造变形分析与测量,结合已有的年代学与沉积学研究,初步提出天水盆地晚新生代以来构造变形序列与构造应力场,重建其晚新生代构造演化历史。详细研究表明,天水盆地晚新生代以来主要经历了3期构造演化:即中新世早-晚期NW-SE向构造伸展,沉积盆地发育,并伴随碱性超基性火山岩喷发和金刚石矿床形成;中新世晚期-早、中更新世NE-SW向挤压,盆地发生构造反转,其动力学背景可能源于晚新生代青藏高原的北东向扩展,指示高原物质扩散开始显著影响到西秦岭地区;晚更新世以来受近N-S向伸展作用控制,盆地发生向东有限挤出并伴随顺时针旋转,主要由于青藏高原向北东扩展过程中,区域构造挤压应力方向发生顺时针偏转所致。     

Spatial variability of the Purbeck–Wight Fault Zone—a long-lived tectonic element in the southern UK

New seamless onshore to offshore bedrock (1:10 k scale) mapping for the Lyme Bay area is used to resolve the westward termination of the Purbeck–Wight Fault Zone (PWFZ) structure, comprising one of the most prominent, long-lived (Variscan–Cimmerian–Alpine) structural lineaments in the southern UK. The study area lies south of the Variscan Frontal Thrust and overlays the basement Variscide Rhenohercynian Zone, in a region of dominant E-W tectonic fabric and a secondary conjugate NW-SE/NE-SW fabric. The PWFZ comprises one of the E-W major structures, with a typical history including Permian to early Cretaceous growth movement (relating to basement Variscan Thrust reactivation) followed by significant Alpine (Helvetic) inversion. Previous interpretations of the PWFZ have been limited by the low resolution (1:250 k scale) of the available offshore BGS mapping, and our study fills this gap. We describe a significant change in structural style of the fault zone from east to west. In the Weymouth Bay area, previous studies demonstrate the development of focussed strain associated with the PWFZ, accompanied by distributed strain, N-S fault development, and potential basement uplift in its hangingwall. In the Lyme Bay area to the west, faulting is dominantly E-W, with N-S faulting absent. Comparison of the newly mapped faulting networks to gravity data suggests a spatial relationship between this faulting variation and basement variability and uplift.     

鄂尔多斯盆地东南部中生界地层节理发育特征与古应力场

鄂尔多斯盆地东南部中生代地层中发育有六组节理(E-W、N-S、ENE-WSW、NNW-SSE、WNW-ESE、NNE-SSW),并且构成三期的正交节理系统(E-W与N-S、ENE-WSW与NNW-SSE、WNW-ESE与NNE-SSW).三期正交节理系统形成的先后期次为:E-W向和N-S向两组节理最早形成,WNW-ESE向和NNE-SSW向两组节理为第二期形成,ENE-WSW向和NNW-SSE向两组节理则最晚形成.E-W向、N-S向和ENE-WSW向三组节理的节理间距指数(FSI)分析结果表明,节理间距的发育程度除了受岩层厚度控制外,还受区域应力场的控制.E-W向、N-S向和ENE-WSW向三组节理的节理间距率(FSR)值分布范围指示不同组节理在区域上发育程度具有差异性.此外,E-W向的优势节理组的FSR值有超过间距与层厚比值的临界值,而非优势组的SN向节理的FSR值则全部小于临界值,表明E-W向和N-S向两组节理组成最早一期的正交节理系统.盆内中生代地层中的三期正交节理系统,所对应的古应力场分别为:(1)晚侏罗世盆地处在近E-W向的挤压环境下,形成了第一期正交节理系统,为E-W向和N-S向两组节理;应力来源于古太平洋板块向欧亚板块俯冲所产生的NW-SE向的挤压分量.(2)晚白垩世时,来自于古太平洋板块俯冲产生的NW-SE向挤压应力形成了第二期正交节理系统的WNW-ESE向和NNE-SSW向两组节理.(3)晚白垩世末至新生代,印度板块向欧亚板块下的俯冲产生NE-SW向的远程挤压应力,形成第三期正交节理系统的ENE-WSW向和NNW-SSE向两组节理.     

Lithospheric folding in the southern North Sea: combined effects of Alpine compression and North Atlantic Ocean opening

Late Cretaceous to Palaeogene graben inversion in the southern North Sea is classically related to Alpine compression. Regional deformation analysis of Upper Cretaceous sediments based on seismic and well data reveals the existence of large-scale NW-SE folds. Folding patterns are interpreted as the result of lithospheric buckling during NE-SW shortening. We suggest that graben inversion at the scale of the southern North Sea is only a part of a more general process, involving lithospheric folding. Folding developed in response to two major plate boundary conditions, that is, E-W to NE-SW opening of the Atlantic Ocean constrained to the southeast by N-S Alpine collision. Lithospheric folding might have influenced both the oil generation process and reservoir properties in this area.     

Compressive Tectonics around Tibetan Plateau Edges

Various earthquake fault types, mechanism solutions, stress field, and other geophysical data were analyzed for study on the crust movement in the Tibetan plateau and its tectonic implications. The results show that numbers of thrust fault and strike-slip fault type earthquakes with strong compressive stress near NNE-SSW direction occurred in the edges around the plateau except the eastern boundary. Some normal faulting type earthquakes concentrate in the Central Tibetan plateau. The strikes of fault planes of thrust and strike-slip faulting earthquakes are almost in the E-W direction based on the analyses of the Wulff stereonet diagrams of fault plane solutions. This implies that the dislocation slip vectors of the thrust and strike-slip faulting type events have quite great components in the N-S direction. The compression motion mainly probably plays the tectonic active regime around the plateau edges. The compressive stress in N-S or NE-SW directions predominates earthquake occurrence in the thrust and strike-slip faulting event region around the plateau. The compressive motion around the Tibetan plateau edge is attributable to the northward motion of the Indian subcontinent plate. The northward motion of the Tibetan plateau shortened in the N-S direction encounters probably strong obstructions at the western and northern margins.     

渤中坳陷中部地区构造应力场光弹模拟实验研究

在对渤中地区沉积构造详细分析的基础上,明确了其中部地区断裂的分布特征,采用以E44-6101型环氧树脂为基体,顺丁烯二酸酐为固化剂,邻苯二甲酸二丁脂为增塑所配制的材料制成渤中中部地质结构模型,对渤中坳陷中部地区构造应力场进行了光弹实验模拟,再现了近北北东向和近东西向断裂在晚近构造格局下的应力状态及分布。试验证明,在构造应力场的作用下,油气往往由高应力值区向低应力值区迁移,而且渤中地区自新近系以来,最大主压应力方向比较稳定。基于试验结果的分析,对北北东向和近东西向两组断裂在晚近应力场的作用下的构造特征及其对油气的控制作用进行讨论。由于渤中坳陷是中国的油气主要产地,通过研究盆地构造应力场的分布,可为盆地的油气勘探和开发提供依据。     

Correlation between the structural pattern and the development of the hydrographic network in a portion of the Western Thessaly Basin (Greece)

In the context of the present study the structural pattern in the Western Thessaly Basin (Greece) has been examined, based on structural data collected from the entire study area that were further correlated to the hydrographic network. The structural pattern of the area was revealed from tectonic analysis. Additionally, the topography, stratigraphy and sedimentology of the study area were taken into account. GIS techniques were used to map the spatial distribution of the geological and tectonic features on the topographic relief of the area. The oldest structures are contractional in nature, deformed by normal faulting related to the extensional episodes initiated in Serravallian times. It is inferred that the orientation of the stress field in the area has changed several times: the N-S stress field which was dominant during Late Serravallian times changed to NW-SE (Messinian-Zanclian) up to E-W in Zanclian and subsequently to roughly NNW-SSE (in late Piacencian). The NE-SW stress that was dominant in Pleistocene became N-S in later times. In addition, some changes in orientation are also indicated for the transitional periods of the pre-mentioned extensional episodes, possibly related to local events, or as a block-related deformation. The development of the 7^th order streams is probably related to the N-S extensional faulting initiated in Pliocene times, while the dominant direction of the 6^th, 5^th and 4^th order streams is possibly connected with the presence of the NNE-SSW and NW-SE extensional faults. Finally, the lower order streams are probably related to the most recent E-W striking normal faults.     

黔西北纳雍-水城一带构造变形特征及其演化

黔西北纳雍-水城一带位于扬子板块西南缘,区内断裂和褶皱极为发育。通过详细野外地质调查,并结合沉积地层接触关系,对区内构造行迹及其组合特征、构造变形期次和构造演化进行探讨。研究表明,震旦纪末至中侏罗世纳雍-水城一带经历了多次构造事件,特别是广西构造事件和印支期构造事件,导致明显的差异剥蚀,但均未造成地层褶皱变形,地层间表现为平行不整合接触。晚侏罗世以后的燕山构造期和喜山构造期才是区内发生构造变形的重要时期。纳雍-水城一带发育的NE-SW、NW-SE及近E-W向三组构造以及在NE-SW、NW-SE向两组构造交接转换部位发育的穹窿构造、构造盆地,均为侏罗纪晚期至早白垩世时期强烈构造事件的产物。其中NE-SW向褶皱及近E-W向断层先期形成,NW-SE向褶皱后期形成,并对先期形成的NE-SW向褶皱进行叠加改造。     

羌塘盆地构造应力场初步分析

地处青藏高原腹地的羌塘盆地构造以EW向褶皱和逆(冲)断层及NW向、NE向平移断层为主,偶见NW向、NE向褶皱和近SN向正断层。据构造组合分析、构造解析研究、数理计算及有限单元法模拟,盆地构造变形应力场最大主应力方位以近SN向为主,伴有NW-SE向、NE-SW向和近EW向。表明自印支运动以来长期处于SN向强烈挤压,伴随间歇性(或派生)NE-SW、NW-SE和近EW向挤压。      

Cretaceous deformation history of the middle Tan-Lu fault zone in Shandong Province, eastern China

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.     

东至断裂带构造变形特征及其构造演化

东至断裂带是皖西南一条重要的北北东向断裂带。详细的构造解析表明,该断裂带主要经过3期构造变形,分别是发生在晚侏罗世末—早白垩世初的左行平移断层、早白垩世期间的伸展构造和晚白垩世—新生代的右行平移断层。通过断层擦痕矢量反演和断层叠加改造关系分析,认为东至断裂带及其两侧多期构造变形对应的区域应力场分别为近南北向挤压、北北西—南南东向挤压、北西—南东向伸展和近东西向挤压应力场。东至断裂带的形成和演化与郯庐断裂带相似,主要与华南与华北板块俯冲碰撞、伊泽奈崎板块和古太平洋板块向欧亚板块俯冲碰撞与弧后扩张、及印度板块向北碰撞后产生向东的构造挤出等多构造体制共同作用有关。