乌鲁木齐山前坳陷逆断裂-褶皱带及其形成机制

乌鲁木齐山前坳陷位于天山新生代再生造山带北侧,南以准噶尔南缘断裂与天山相隔,内部发育了几排逆断裂 背斜带,每一排构造带又由多个逆断裂 背斜组成。最南的齐古逆断裂 背斜带形成于中生代末,其北的玛纳斯逆断裂背斜带包含霍尔果斯、玛纳斯和吐谷鲁逆断裂背斜,形成于上新世末、早更新世初,受上、下２ 个滑脱面和断坡的控制,形成上、下２ 个背斜。再向北的独山子逆断裂背斜带由独山子、哈拉安德和安集海逆断裂背斜组成,形成于早、中更新世之间,主逆断裂向下在８ ～９ ｋｍ 深处的侏罗系中变为近水平滑脱面。此外,在独山子和吐谷鲁背斜的西北和东北还分别发育有正在形成之中的西湖和呼图壁隆起。研究了这些逆断裂 背斜带的地表和深部的构造特征、二维和三维几何学及运动学后指出,它们是在天山向准噶尔盆地扩展过程中发育于近水平滑脱面和不同断坡上的断展褶皱,独山子和安集海逆断裂 背斜的水平缩短量分别为２ ９００ ,１ ３５０ ｍ ,缩短速率分别为３９７ ,１８７ ｍ ｍ／ ａ。霍尔果斯、玛纳斯、吐谷鲁逆断裂 背斜的水平缩短量分别为５ ９００ ,６ ５００ ,６ ０００ ｍ ,相应的缩短速率分别为２０２,２２３ ,２０６ ｍ ｍ／ａ,准噶尔南缘断裂和乌鲁木齐山前坳陷第四纪?     

Late Cretaceous–Cenozoic intraplate contractional deformation at the Norwegian continental shelf: timing, magnitude and regional implications

Contractional structures (large anticlines and synclines, reverse faults and inverted centres of deposition) of assumed Late Cretaceous–Cenozoic age are common in Cretaceous–Tertiary basins of the northwestern European margin. The similarities in style, orientation and timing of these structures are striking. The present detailed analysis of one anticline (the Ormen Lange Dome) of the mid-Norwegian continental shelf indicates that the total contraction is moderate (less than 2–3%), and that the analysed anticline has been growing almost continuously since its initiation in Eocene till Present. Inversion in the Barents Sea started already in the Late Cretaceous. This episode is suggested to be related to far-field effects of active plate-margin processes, and transfer of stresses across the plate as a consequence of the sub Hercynian and Paleocene ‘Laramide' event of the Alpine Orogeny. The development of co-axial structures was facilitated by stress focusing along pre-existing, high-relief N–S- and NE–SW-trending fault complexes. Far-field plate tectonic stresses originating mainly from the Alpine Orogeny seem to have been the most important cause of contractional deformation on the NW European shelf. In addition, ridge push from the North Atlantic spreading may have contributed significantly, particularly during the Neogene.     

Tectono-geomorphic development of intra-continental Cenozoic depressions within Cretaceous rocks of the Interior Homocline,Central Arabia

Intra-continental depressions occurred in Central Arabia, within the evaporite-bearing Sulaiy Formation, and extends for over 550 km along N-S arcuate belt, passing through eastern Ar Riyadh, Saudi Arabia. They mark Jurassic/Cretaceous contact within the Interior Homocline of Central Arabia, accommodating Neogene and Quaternary deposits. Two en echelon major depressional areas were discovered, the northern major depressional area and the southern major depressional area. The first depressional area occurs between Al Artawiyah and Ad Dilam towns, following the arcuate Jurassic/Cretaceous contact. It contains five depressions: N-S Al Artwaiyah depression; NW-SE Ath Thumamah depression, northeast of Riyadh; NW-SE Jinadriyah depression, east of Riyadh; E-W Al Kharj depression; and N-S Ad Dilam depression. All five depressions seems to be formed by tectonic and subsequent geomorphic events, except for Al Artawiyah and Jinadriyah depression, which developed mainly by tectonic events. Southern major depressional area steps over to southwest of Ad Dilam, and occurs from Hawtat bani tamim to Layla towns. This Hawtah-Layla major depression trends N-S, and Cretaceous units strike NNE, which is a slightly oblique relationship, suggesting expression of deep-seated structures. Tectonic features were part of the Alpine-Himalayan orogeny, developing during Eocene. They followed by a geomorphic event (karsts and subsequent collapse) that took place during Mid Pleistocene. Ad Dilam depression is a surface expression of three oil and gas fields, while the southern major depression between Hawtat Bani Tamim and Layla towns is a surface expression of four oil and gas fields. Yet, other several depressional areas are also accommodating Quaternary desert sediments, and they contain economic resources, which therefore, worth further detailed studies.     

Structural architecture and tectonic evolution of the Maghara inverted basin,Northern Sinai,Egypt

Large NE–SW oriented asymmetric inversion anticlines bounded on their southeastern sides by reverse faults affect the exposed Mesozoic and Cenozoic sedimentary rocks of the Maghara area (northern Sinai). Seismic data indicate an earlier Jurassic rifting phase and surface structures indicate Late Cretaceous-Early Tertiary inversion phase. The geometry of the early extensional fault system clearly affected the sense of slip of the inverted faults and the geometry of the inversion anticlines. Rift-parallel fault segments were reactivated by reverse slip whereas rift-oblique fault segments were reactivated as oblique-slip faults or lateral/oblique ramps. New syn-inversion faults include two short conjugate strike-slip sets dissecting the forelimbs of inversion anticlines and the inverted faults as well as a set of transverse normal faults dissecting the backlimbs. Small anticline–syncline fold pairs ornamenting the steep flanks of the inversion anticlines are located at the transfer zones between en echelon segments of the inverted faults.     

西藏日喀则群昂仁组时代问题新资料

昂仁组是一套复理石和类复理石沉积,含晚白垩世土伦期的菊石Mammites^[1,2],但因未发现直接的上覆地层和化石稀少而不能肯定是否还包括晚于土伦期或至早第三纪的沉积^[1,3]。1980年,笔者在昂仁、萨噶一带的昂仁组中采到瓣鳃、腹足化石;我局区调队在仲巴县错江顶一带,发现连续沉积于昂仁组之上,整合于下第三系之下一套含Masstrichtian期菊石(Sphenodiscus)的杂色地层。本文报道这一发现和对昂仁组时代问题的认识(图1)。     

内华达北中部新月谷—独立金矿区线性构造带的证据

内华达北中部的新月谷-独立金矿区线性构造(CVIL)是一个呈20°～30°走向、具多期变形、侵入及热液活动的构造带,该带从独立金矿区向南至科特兹矿山附近延伸达90 km,经过科特兹-派普来恩、卡林及独立三个主要的沉积岩型金矿区,含有罗伯茨山异地岩(可能是奥陶系Vinini组)的强烈构造岩,NE向的断层,白垩或第三纪的NE向的岩墙.变形带的组构具混杂岩的特点,但混杂岩中也显示有与晚三叠世和晚侏罗世之间形成的褶皱展布方向一致的定向组构.此外,沿CVIL带局部出现有第三纪的碧玉状岩石、角砾岩、方解石脉及脱钙蚀变作用.CVIL构造带南北两端成群出现的沉积岩型金矿床具有与卡林矿带金矿床相同的矿物特征.上述二个矿区都有NE向的断层,穿越罗伯茨山异地岩上盘中的构造窗和构造高地.CVIL可能是形成某些金矿床的主要热液通道.     

香龙山背斜几何学、运动学及成因机制

华南板块北侧大巴山构造带和内部雪峰山构造带的关系是华南板块陆内构造变形研究的重要内容。香龙山背斜位于大巴山构造带和雪峰山构造带之间,记录了两构造带相互复合、相互协调的重要信息。为研究香龙山背斜的几何学、运动学特征,分析其形成机制,本次研究利用香龙山地区最新的地震剖面,结合地质图分析、浅表地质剖面绘制等手段,取得了如下结论：1） 香龙山背斜为一短轴状背斜,背斜具有较为宽阔、平坦的顶部和较短的两翼,其西南侧发育构造鼻;2） 香龙山背斜的主要运动学模型为下部断层转折褶皱与上部构造楔复合的模型,其地层变形受到基底物质堆叠抬升的影响;3） 香龙山背斜形成于晚侏罗世-早白垩世,在古近纪遭受改造,这两个变形时期分别对应了香龙山背斜形成现今形态的两个阶段。香龙山背斜南北方向上缩短了11.4 km,缩短率为22.7%;4） 香龙山背斜是在雪峰山构造带北向挤压作用下,由来自大巴山构造带、雪峰山构造带的共同作用力形成的,后期改造作用可能受控于青藏高原了隆升对整个中国中、西部的影响。     

Andean oblique folds in the Cordillera Oriental – Northwestern Argentina: Insights from analogue models

The dominant Cenozoic structural grain in northwestern Argentina trends north–south. However, several oblique folds have been mapped, mainly in the Cordillera Oriental and the Sistema de Santa Bárbara. Two oblique NE–SW-trending anticlines are well exposed in the Luracatao Valley-Salta, along the western border of the Cordillera Oriental. These oblique anticlines are defined by the Palaeogene Santa Bárbara Subgroup and are cut by the reverse faults bounding the Luracatao Valley. We constructed analogue models to simulate the generation of oblique NE–SW anticlines inside the narrow, trough-like Luracatao Valley. Orthogonal compression and basement oblique heterogeneities, oblique compression and basement oblique heterogeneities, and oblique compression configurations were tested in the models. The first two configurations simulate the anticline formation well. In addition, we analyse dextral rotation and the influence of Neoproterozoic basement/Cretaceous rift structures as the cause of the oblique orientation. The analogue models suggest pre-Andean oblique structures controlling the oblique orientation of these Andean folds despite being a second-order planes of weakness.     

Seismic stratigraphy of the Quaternary and its substratum in southeastern Kattegat, Scandinavia

Based on c. 1500 km reflection seismic profiles, the Quaternary formations and their pre-Quaternary substratum in the southeastern Kattegat are described and a geological interpretation is suggested. The major volume of Quaternary deposits is found in a broad north-northwest south-southeast trending topographic depression. The substratum consists of Upper Cretaceous limestone in the region north of the Sorgenfrei–Tornquist Zone, and inside this zone older Mesozoic sedimentary rocks and Precambrian crystalline rocks are found. The Quaternary is divided into four seismic units. No direct stratigraphic control is available, but the units are assumed to represent a period ranging from Late Saalian to Holocene. The oldest unit (unit 3) is composed of deposits of supposed Late Saalian to Middle Weichselian age. This unit was severely eroded probably by the Late Weichselian ice sheets in a zone extending 40–50 km from the Swedish coast. Unit 2 represents the Late Weichselian till deposits. North and east of the island of Anholt unit 3 is cut by a system of channels eroded by glacial meltwater. By the erosion a relief up to c. 100 m was formed. After the recession of the Late Weichselian ice, an up to 100 m thick sequence of water-lain sediments (unit 1) was deposited in the erosional basin and channels. Holocene deposits (unit 0) of considerable thickness have only been identified in the channels in the northern part of the area.     

西秦岭北缘断裂带漳县—车厂断层的结构及构造演化

西秦岭北缘断裂带是青藏高原东北缘主要构造边界断裂带之一, 其构造变形历史和运动学特征研究可以为西秦岭中新生代构造过程和印度—亚洲板块碰撞动力学的远程构造响应提供约束。漳县—车厂断层是西秦岭北缘断裂带的重要组成部分, 通过对工程开挖所揭露的断层带内丰富构造现象的观测与分析, 至少可以辨别出3期性质、规模、运动学特征各异的构造变形事件。第一期为向北北东陡倾的伸展正断层作用; 第二期为向南南西倾的由南向北的逆冲断层作用; 第三期为沿近直立断面左旋走滑作用。尽管每期变形的时代尚缺乏构造物质测年的约束, 但根据其与白垩系、新近系的空间关系以及已有第四纪以来沿断层地貌位错和相关沉积物测年以及地震活动历史研究对断层左旋走滑作用的时代约束, 认为第一期伸展正断层作用起始于早白垩纪, 可能持续到渐新世; 第二期向北逆冲断层作用起始于渐新世初, 可能持续到早第四纪; 第三期左旋走滑断层作用起始于晚第四纪, 持续至今。漳县—车厂断层是一条典型的多期变形的脆性断层, 其变形特征与历史, 如果代表了西秦岭北缘断裂带特征与构造变形过程, 那么现今西秦岭北缘断裂带仅是起始于早白垩纪、新生的脆性断裂带, 并非是印支主造山期大规模韧性逆冲推覆作用的边界断层。     

南华北盆地断裂构造特征与油气勘探

南华北盆地主要发育3期断裂:第一期是在三叠纪末挤压构造背景下形成的逆冲断裂,断裂走向以近E-W向为主、主要由南向北逆冲;第二期是与晚侏罗世一早白垩世构造运动相关的走滑拉张断裂,断裂走向以NNE向为主,左行走滑,常沿印支期挤压断裂带发育;第三期是与晚白垩世一古近纪构造运动相关的正断裂,断裂走向以近S・N向或NEE向为主。三叠纪末印支期断裂的冲断抬升作用一方面使该区主力炷源岩石炭一二叠系受严重剥蚀,另一方面破坏了炷源岩的连续性和稳定性;晚侏罗世一早白垩世的走滑拉张断裂与印支期断裂一起,呈棋盘格式平面切割了南华北盆地,与之伴生的火成岩对绘源岩也有一定的破坏作用;晚白垩世一古近纪的拉张断裂则进一步加强了坯源岩的不连续性。后两期拉张断裂常常通天,对前期形成的油气藏有一定的破坏作用。因此,对于南华北盆地的油气勘探,需要避开走滑断裂或拉张断裂,避开火成岩体;针对上古生界,要寻找连续性较好的绘源岩层;针对中、新生界,要寻找有利于绘源岩发育的沉积相带。     

郯庐断裂带肥东段烟头山及桃源地区构造变形特征研究

郯庐断裂带肥东段烟头山及桃源地区,发育多条左行韧性剪切带,岩性以糜棱岩和糜棱岩化片麻岩为主,岩石变形强烈。通过详细的野外观测及室内分析发现：肥东北部烟头山及桃园地区几何学形态呈一背形构造,其枢纽走向NE-SW,轴面倾向SE,自核部向两翼岩性出露具有一定的规律性和对称性。古应力方向及运动学涡度研究表明：研究区内构造体主要受到近南北方向的挤压,涡度值W_k在0.73～0.90之间,指示区域内的韧性剪切活动以简单剪切为主。对区内变形岩石展开精细化的构造变形分析,包括石英的分形特征、变质变形温度估计、差应力和应变速率的计算等,结果显示：区内动态重结晶石英颗粒边界具有统计学上的自相似性,分维值D在1.111～1.187之间,变质变形温度集中在520 ℃～610 ℃之间,为高绿片岩相到低角闪岩相变质;韧性剪切带的差异应力Δσ介于18.493～95.266 MPa之间,应变速率ε范围在5.418×10^-15 s^-1～4.748×10^-11 s^-1之间。对比以上参数发现：韧性剪切带核部和背形转折端附近,岩石变形强烈,变质变形温度高,动态重结晶石英颗粒粒径较小,分维值较大,差异应力和应变速率也较大,远离剪切带核部和背形两翼则相反。本文从几何学、运动学特征以及显微构造变形分析等方面展开精细化研究,对进一步认识郯庐断裂带乃至大型韧性剪切带的构造样式和演化过程有着重要的意义。     

Wrench structural deformation in Ras Al Hilal-Al Athrun area, NE Libya: a new contribution in Northern Al Jabal Al Akhdar Belt

Al Jabal Al Akhdar is a NE/SW- to ENE/WSW-trending mobile part in Northern Cyrenaica province and is considered a large sedimentary belt in northeast Libya. Ras Al Hilal-Al Athrun area is situated in the northern part of this belt and is covered by Upper Cretaceous–Tertiary sedimentary successions with small outcrops of Quaternary deposits. Unmappable and very restricted thin layers of Palaeocene rocks are also encountered, but still under debate whether they are formed in situ or represent allochthonous remnants of Palaeocene age. The Upper Cretaceous rocks form low-lying to unmappable exposures and occupy the core of a major WSW-plunging anticline. To the west, south, and southeast, they are flanked by high-relief Eocene, Oligocene, and Lower Miocene rocks. Detailed structural analyses indicated structural inversion during Late Cretaceous–Miocene times in response to a right lateral compressional shear. The structural pattern is themed by the development of an E–W major shear zone that confines inside a system of wrench tectonics proceeded elsewhere by transpression. The deformation within this system revealed three phases of consistent ductile and brittle structures (D₁, D₂, and D₃) conformable with three main tectonic stages during Late Cretaceous, Eocene, and Oligocene–Early Miocene times. Quaternary deposits, however, showed at a local scale some of brittle structures accommodated with such deformation and thus reflect the continuity of wrenching post-the Miocene. D₁ deformation is manifested, in Late Cretaceous, via pure wrenching to convergent wrenching and formation of common E- to ENE-plunging folds. These folds are minor, tight, overturned, upright, and recumbent. They are accompanied with WNW–ESE to E–W dextral and N–S sinistral strike-slip faults, reverse to thrust faults and pop-up or flower structures. D₂ deformation initiated at the end of Lutetian (Middle Eocene) by wrenching and elsewhere transpression then enhanced by the development of minor ENE–WSW to E–W asymmetric, close, and, rarely, recumbent folds as well as rejuvenation of the Late Cretaceous strike-slip faults and formation of minor NNW–SSE normal faults. At the end of Eocene, D₂ led to localization of the movement within E–W major shear zone, formation of the early stage of the WSW-plunging Ras Al Hilal major anticline, preservation of the contemporaneity (at a major scale) between the synthetic WNW–ESE to E–W and ENE–WSW strike-slip faults and antithetic N–S strike-slip faults, and continuity of the NW–SE normal faults. D₃ deformation is continued, during the Oligocene-Early Miocene, with the appearance of a spectacular feature of the major anticline and reactivation along the E–W shear zone and the preexisting faults. Estimating stress directions assumed an acted principal horizontal stress from the NNW (N33°W) direction.     

Magnitude of lateral displacement on the Crevillente Fault Zone (Betic Cordillera,SE Spain): stratigraphical and sedimentological considerations

The Crevillente Fault Zone (CFZ) comprises a system of northeast to southwest oriented dextral faults that extend for some 600 km in the External Zones of the Betic Cordillera (SE Spain). The magnitude of lateral displacement related to this fault zone is not well constrained, and it is considered to be between 20 and 400 km. The stratigraphical and sedimentological criteria used in this work have proven effective in quantifying the magnitude of the displacement along this structure. We have analysed an oolitic turbidite facies in the Middle Jurassic of the Sierra de Ricote (Median Subbetic of Murcia Province). A detailed revision of ooidal limestone outcrops has revealed that the source area of these deposits was to the Internal Subbetic zone, north of Vélez Rubio (Almería Province). These two tectonic units, the Median and Internal Subbetic, are currently 75 km from each other and separated by the CFZ. The conclusions arising from our stratigraphical, petrological and sedimentological studies favour interpretation of a 75–100 km lateral displacement. After restoring the Late Jurassic–Cretaceous anticlockwise rotation of Iberia, the CFZ appears to belong to the E–W palaeofault system that is related to the extension of the South Iberian Continental Margin (SICM). Copyright © 2004 John Wiley & Sons, Ltd.     

Mesozoic intracontinental orogeny in the Qinling Mountains,central China

The Qinling Orogenic belt has been well documented that it was formed by multiple steps of convergence and subsequent collision between the North China and South China Blocks during Paleozoic and Late Triassic times. Following the collision in Late Triassic times, the whole range evolved into an intracontinental tectonic process. The geological, geophysical and geochronological data suggest that the intracontinental tectonic evolutionary history of the Qinling Orogenic Belt allow deduce three stages including strike-slip faulting during Early Jurrassic, N-S compressional deformation during Late Jurassic to Early Cretaceous and orogenic collapse during Late Cretaceous to Paleogene. The strike-slip faulting and the infills in Early Jurassic along some major boundary faults show flower structures and pull-apart basins, related to the continued compression after Late Triassic collision between the South Qinling Belt and the South China Block along the Mianlue suture. Late Jurassic to Early Cretaceous large scale of N-S compression and overthrusting progressed outwards from inner of Qinling Orogen to the North China Block and South China Block, due to the renewed southward intracontinental subduction of the North China Block beneath the Qinling Orogenic Belt and continuously northward subduction of the South China Block, respectively. After the Late Jurassic-Early Cretaceous compression and denudation, the Qinling Orogenic Belt evolved into Late Cretaceous to Paleogene orogen collapse and depression, and formed many large fault basins along the major faults.     

Dynamics and inversion of the Mesozoic Basin of the Weald–Boulonnais area: role of basement reactivation

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.     

Control of Cambrian evaporites on fracturing in fault-related anticlines in the Zagros fold-and-thrust belt

Orientation and distribution of fractures in the Oligocene–Early Miocene Asmari Formation (a major reservoir rock of the Zagros petroleum system) were investigated in two anticlines of the Zagros fold-and-thrust belt. The Sim and Kuh-e-Asmari anticlines developed in the areas of the Zagros characterized by the occurrence and absence of Cambrian evaporites at the bottom of the stratigraphic pile, respectively. The aim was to outline major differences in terms of fracture spacing and saturation. Organic matter maturity and clay minerals-based geothermometers suggest that the depth of deformation for the top of the Asmari Formation in the Kuh-e-Asmari anticline was in the range of 1.5–2.7 km assuming a geothermal gradient of 22.5 °C/km. The Asmari Formation in the Sim anticline probably experienced a slightly deeper sedimentary burial (maximum 3 km) with a geothermal gradient of 20 °C/km. The spacing of fractures is generally 2–3 times larger (i.e., strain accommodated by fracturing is smaller) in the Sim anticline than in the Kuh-e-Asmari anticline. This is consistent with regional geological studies, analogue, and numerical models that suggest that thrust faults geometry and related folds are markedly different in the absence or presence of a weak decòllement (evaporites). The larger spacing in the Sim anticline is also consistent with higher temperature predicted for the Asmari Formation in this area. By contrast, the orientation of fractures with respect to the fold axes is the same in both anticlines. The fracture systems are rather immature in both anticlines. The amount and density of fractures in the twofolds are controlled by regional (occurrence/absence of salt and probably different burial), rather than local features (fold geometry).     

四川盆地西北部新生代构造变形模式讨论——对认识青藏高原东北缘新生代变形机制的意义

综合造山带内的构造热年代学及盆地内部进行的磷灰石裂变径迹研究,提出了四川盆地西北部的三个背斜（潼梓关背斜、九龙山背斜和南阳坝背斜）主要是新生代构造变形的产物。野外观察发现汉中盆地是一个第四纪的拉分盆地,其主控断层具左行走滑性质。新生代青藏高原东缘大型地块向东挤出,遭遇强硬的四川克拉通阻挡之后,沿着龙门山形成了一个右行的走滑挤压带,并且影响到邻近的四川盆地,形成北东向背斜。这期构造变形往北延伸进入米仓山,形成具有逆冲性质的北东向断层。四川盆地北面也存在向东的挤出作用,这和汉中盆地主控断层的左行走滑性质是匹配的。四川盆地北面的地块挤出影响了米仓山前缘的四川盆地,由于龙门山和米仓山构造变形的叠加,使得最东面的南阳坝背斜相对于其它两个背斜在褶皱轴上发生了偏转。     

赣江断裂带中生代的演化及其地球动力学背景

赣江断裂带是江西省境内醒目的北北东向平移断裂构造带,由一系列北北东向、北东向和北西向断裂束组成,表现为一个大规模的左行走滑脆性剪切带并兼具伸展断陷和右旋走滑的成份。赣江断裂带在重力、航磁异常呈现为显著的梯度带,是一条晚中生代的岩浆岩带,控制了以鄱阳盆地为代表的一系列白垩纪-古近纪沉积盆地的形成与发育。该带在中生代的演化可分为早-中侏罗世压扭、晚侏罗早-白垩世左行平移和晚白垩世上盘斜落的右行平移3个阶段。在侏罗纪以来太平洋板块对欧亚大陆斜向俯冲的大背景下,赣江断裂带的形成和演化与华南广为发育的燕山期陆内造山作用密切相关,北北东向断裂的发育则直接受郯庐断裂早白垩世左行走滑活动控制,因而表现出“北强南弱”和“北早南晚”的特点。白垩纪时赣江断裂的活动方式与郯庐断裂一致,可认为是后者的南延。     

A Section Across a Tethyan Suture in Northwestern Turkey

A section across a major Tethyan suture in northwestern Turkey is described in detail. The suture of Early Tertiary age juxtaposes two continental blocks with distinct stratigraphic, structural, and metamorphic features. The Sakarya Zone in the north is represented by Permo-Triassic accretion-subduction complexes, which are unconformably overlain by Jurassic to Paleocene sedimentary rocks. The Anatolide-Tauride Block to the south of the suture consists of two tectonic zones. The Tavsanli Zone consists of a coherent blueschist sequence with Late Cretaceous isotopic ages. This blueschist sequence is tectonically overlain by Cretaceous oceanic accretionary complexes and peridotite slabs. The Bornova Flysch Zone consists of Triassic to Cretaceous limestone blocks in an uppermost Cretaceous to Paleocene flysch. The suture is represented by a N-vergent thrust fault separating lithologies from these two continental blocks.

The orogenic history of the region can be considered in two stages. In the Late Cretaceous, the northern margin of the Anatolide-Tauride Block was subducted under the Tethyan oceanic lithosphere and was metamorphosed in blueschist-facies conditions. Blueschists were largely exhumed by the latest Cretaceous or early Paleocene, prior to the continental collision. In the second stage, during the Paleocene, the continent-continent collision produced a doubly vergent orogen involving both S- and N-vergent thrusting, but did not lead to major crustal thickening.