Stratigraphic and structural evolution of the Blue Nile Basin,Northwestern Ethiopian Plateau

The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains ∼1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early–Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue Nile Basin has evolved in three main phases: (1) pre‐sedimentation phase, include pre‐rift peneplanation of the Neoproterozoic basement rocks, possibly during Palaeozoic time; (2) sedimentation phase from Triassic to Early Cretaceous, including: (a) Triassic–Early Jurassic fluvial sedimentation (Lower Sandstone, ∼300 m thick); (b) Early Jurassic marine transgression (glauconitic sandy mudstone, ∼30 m thick); (c) Early–Middle Jurassic deepening of the basin (Lower Limestone, ∼450 m thick); (d) desiccation of the basin and deposition of Early–Middle Jurassic gypsum; (e) Middle–Late Jurassic marine transgression (Upper Limestone, ∼400 m thick); (f) Late Jurassic–Early Cretaceous basin‐uplift and marine regression (alluvial/fluvial Upper Sandstone, ∼280 m thick); (3) the post‐sedimentation phase, including Early–Late Oligocene eruption of 500–2000 m thick Lower volcanic rocks, related to the Afar Mantle Plume and emplacement of ∼300 m thick Quaternary Upper volcanic rocks. The Mesozoic to Cenozoic units were deposited during extension attributed to Triassic–Cretaceous NE–SW‐directed extension related to the Mesozoic rifting of Gondwana. The Blue Nile Basin was formed as a NW‐trending rift, within which much of the Mesozoic clastic and marine sediments were deposited. This was followed by Late Miocene NW–SE‐directed extension related to the Main Ethiopian Rift that formed NE‐trending faults, affecting Lower volcanic rocks and the upper part of the Mesozoic section. The region was subsequently affected by Quaternary E–W and NNE–SSW‐directed extensions related to oblique opening of the Main Ethiopian Rift and development of E‐trending transverse faults, as well as NE–SW‐directed extension in southern Afar (related to northeastward separation of the Arabian Plate from the African Plate) and E–W‐directed extensions in western Afar (related to the stepping of the Red Sea axis into Afar). These Quaternary stress regimes resulted in the development of N‐, ESE‐ and NW‐trending extensional structures within the Blue Nile Basin. Copyright © 2008 John Wiley & Sons, Ltd.     

山东鲁西地块断裂构造分布型式与中生代沉积—岩浆—构造演化序列

鲁西地块的断裂构造有两类不同分布型式:一类呈放射状分布, 由陡倾、基底右行韧性剪切带和盖层内复杂力学性质的断裂组成; 另一类呈环绕地块基底核部同心环状分布, 由3个主要盖层伸展拆离带组成, 主滑脱面分别位于古生界盖层与基底间的不整合面、石炭系与奥陶系之间的平行不整合面和中新生代断陷-沉积岩系与新生代火山-沉积物之间的断层。中生代构造变形样式可以分为3个层次:印支期褶皱-逆冲推覆构造、燕山中期NNE轴向的隔槽式箱状褶皱和燕山晚期NW、NNE向共轭正断-走滑断裂。相应地鲁西地块经历了3个成盆期, 即早-中侏罗世、早白垩世和晚白垩世, 这些中生代盆地在空间上的叠置导致了地块内部复杂的盆-山耦合关系。鲁西地块中生代有两个岩浆活动集中时期, 即早侏罗世(约190Ma)和早白垩世(132~110Ma)。综合沉积记录、岩浆活动和构造变形过程, 将鲁西地块中生代构造演化历史划分为6个阶段:晚三叠世挤压变形, 早、中侏罗世弱伸展作用, 中、晚侏罗世挤压变形与地壳增厚作用, 早白垩世大陆裂谷与地壳伸展作用, 早白垩世末期挤压变形与盆地反转事件和晚白垩世区域隆升。这些构造演化阶段和构造事件对研究和理解中生代构造体制和深部岩石圈动力学转换过程具有重要意义。      

Late Mesozoic and Cenozoic rifting and its dynamic setting in Eastern China and adjacent areas

During the Late Mesozoic and Cenozoic, extension was widespread in Eastern China and adjacent areas. The first rifting stage spanned in the Late Jurassic–Early Cretaceous times and covered an area of more than 2 million km² of NE Asia from the Lake Baikal to the Sikhot-Alin in EW direction and from the Mongol–Okhotsk fold belt to North China in NS direction. This rifting was characterized by intracontinental rifts, volcanic eruptions and transform extension along large-scale strike–slip faults. Based on the magmatic activity, filling sequence of basins, tectonic framework and subsidence analysis of basins, the evolution of this area can be divided into three main developmental phases. The first phase, calc-alkaline volcanics erupted intensely along NNE-trending faults, forming Daxing'anling volcanic belt, NE China. The second phase, Basin and Range type fault basin system bearing coal and oil developed in NE Asia. During the third phase, which was marked by the change from synrifting to thermal subsidence, very thick postrift deposits developed in the Songliao basin (the largest oil basin in NE China).Following uplift and denudation, caused by compressional tectonism in the near end of Cretaceous, a Paleogene rifting stage produced widespread continental rift systems and continental margin basins in Eastern China. These rifted basins were usually filled with several kilometers of alluvial and lacustrine deposits and contain a large amount of fossil fuel resources. Integrated research in most of these rifting basins has shown that the basins are characterized by rapid subsidence, relative high paleo-geothermal history and thinned crust. It is now accepted that the formation of most of these basins was related to a lithospheric extensional regime or dextral transtensional regime. During Neogene time, early Tertiary basins in Eastern China entered a postrifting phase, forming regional downwarping. Basin fills formed in a thermal subsidence period onlapped the fault basin margins and were deposited in a broad downwarped lacustrine depression. At the same time, within plate rifting of the Lake Baikal and Shanxi graben climaxed and spreading of the Japan Sea and South China Sea occurred. Quaternary rifting was marked by basalt eruption and accelerated subsidence in the area of Tertiary rifting. The Okinawa Trough is an active rift involving back-arc extension.Continental rifting and marginal sea opening were clearly developed in various kind of tectonic settings. Three rifting styles, intracontinental rifting within fold belt, intracontinental rifting within craton and continental marginal rifting and spreading, are distinguished on the basis of nature of the basin basement, tectonic location of rifting and relations to large strike–slip faults.Changes of convergence rates of India–Eurasia and Pacific–Eurasia may have caused NW–SE-trending extensional stress field dominating the rifting. Asthenospheric upwelling may have well assisted the rifting process. In this paper, a combination model of interactions between plates and deep process of lithosphere has been proposed to explain the rifting process in East China and adjacent areas.The research on the Late Mesozoic and Cenozoic extensional tectonics of East China and adjacent areas is important because of its utility as an indicator of the dynamic setting and deformational mechanisms involved in stretching Lithosphere. The research also benefits the exploration and development of mineral and energy resources in this area.     

Thermochronological evidence for Mesozoic–Tertiary tectonic evolution in the eastern Sardinia

Apatite fission‐track analyses on samples from eastern Sardinia document a complex tectonic history, whose reconstruction is problematic because of the reactivation of faults and structures at different times from Jurassic to Miocene. The oldest ages (150–154 Ma) have been detected on the southern margin of the Gulf of Orosei and are related to the extensional tectonics that characterize the European passive margin during Early and Middle Jurassic times. Thermal modelling of these data allows reconstruction of the burial history of the Mesozoic basin and estimation of a sedimentary thickness of 2000 m. Part of these sediments was eroded during the following uplift, documented by mid‐Cretaceous fission‐track ages. A further exhumation episode of Eocene age has been revealed by fission‐track data on granite samples, and has been inferred to be related to the Alpine orogenic phase. This tectonic episode caused the exhumation of crustal blocks bound by faults that were finally reactivated during the Late Oligocene–Early Miocene.     

Adria,the African promontory,in mesozoic Mediterranean palaeogeography

The orogenic belts encircling the present-day Adriatic Sea are the deformed Mesozoic continental margin of an area known as Adria, the outline of which began to take shape during Middle Triassic continental rifting. Early Jurassic oceanic rifting was usually close to, but not coincident with, sites of earlier continental rifting. The Triassic rifted zones were usually incorporated into the continental margin of Adria, profoundly influencing its subsequent development. The Mesozoic platform/basin morphology of this margin can be correlated along the length of the belt.Palaeomagnetic data from autochthonous outcrops of the foreland of Adria do not indicate relative rotation and moreover suggest that this foreland has moved in coordination with Africa since the Early Mesozoic. Seismic soundings indicate that thick Mesozoic sedimentary sequences which can be correlated with sections on the African platform are continuous beneath the eastern Mediterranean seas. The concept of Adria as having behaved as a promontory of the African plate is tested by correlation of the main tectonic events in the belt with the spreading history of the Atlantic. The simplest model which adequately accounts for available data comprises a continuous Mesozoic continental margin from the Magrebids of Tunisia, through the Apennines, Alps, Dinarides and Hellenides to the alpine belt of Turkey. This margin was the southern margin of the Mesozoic Tethys and its foreland was more or less continuous with the African platform. Some structural and geochemical features of the double ophiolitic belt on the eastern side of Adria may be explained in terms of more external oceanic branches giving a more diversified continental margin of Adria. The present undulations of the Periadriatic belt are mainly a product of Late Cretaceous to recent deformation, which severely modified the shape of this margin by continental collision and by subsequent development of back-arc features.     

Tectonic evolution of Cretaceous extensional basins in Zhejiang Province,eastern South China: structural and geochronological constraints

Widespread Cretaceous volcanic basins are common in eastern South China and are crucial to understanding how the Circum-Pacific and Tethyan plate boundaries evolved and interacted with one another in controlling the tectonic evolution of South China. Lithostratigraphic units in these basins are grouped, in ascending order, into the Early Cretaceous volcanic suite (K_1V), the Yongkang Group (K_1-2), and the Jinqu Group (K₂). SHRIMP U-Pb zircon geochronological results indicate that (1) the Early Cretaceous volcanic suite (K_1V) erupted at 136–129 Ma, (2) the Yongkang Group (K_1-2) was deposited from 129 Ma to 91 Ma, and (3) the deposition of the Jinqu Group (K₂) post-dated 91 Ma. Structural analyses of fault-slip data from these rock units delineate a four-stage tectonic evolution of the basins during Cretaceous to Palaeogene time. The first stage (Early to middle Cretaceous time, 136–91 Ma) was dominated by NW–SE extension, as manifested by voluminous volcanism, initial opening of NE-trending basins, and deposition of the Yongkang Group. This extension was followed during Late Cretaceous time by NW–SE compression that inverted previous rift basins. During the third stage in Late Cretaceous time, possibly since 78.5 Ma, the tectonic stress changed to N–S extension, which led to basin opening and deposition of the Jinqu Group along E-trending faults. This extension probably lasted until early Palaeogene time and was terminated by the latest NE–SW compressional deformation that caused basin inversion again. Geodynamically, the NW–SE-oriented stress fields were associated with plate kinematics along the Circum-Pacific plate boundary, and the extension–compression alternation is interpreted as resulting from variations of the subducted slab dynamics. A drastic change in the tectonic stress field from NW–SE to N–S implies that the Pacific subduction-dominated back-arc extension and shortening were completed in the Late Cretaceous, and simultaneously, that Neo-Tethyan subduction became dominant and exerted a new force on South China. The ongoing Neo-Tethyan subduction might provide plausible geodynamic interpretations for the Late Cretaceous N–S extension-dominated basin rifting, and the subsequent Cenozoic India–Asia collision might explain the early Palaeogene NE–SW compression-dominated basin inversion.     

济阳坳陷中生代地层剥蚀厚度、原始厚度恢复及原型盆地研究

在采用各种地层剥蚀量的计算方法对济阳坳陷中生代各主要不整合面地层剥蚀厚度恢复的基础上,结合钻井及地震资料,对中生代各主要构造层的原始地层厚度进行了恢复。以此为切入点,对济阳坳陷区中生代盆地原型进行了初步探讨,将其划分为5期盆地原型：早-中三叠世为一大型内陆坳陷盆地;晚三叠世整体挤压抬升剥蚀;早-中侏罗世为弱挤压背景下的山间盆地;晚侏罗世-早白垩世为受正断层控制的断陷盆地;晚白垩世为断陷后的坳陷盆地。     

南海北部—东海南部中生代盆地演化与油气资源潜力

目前的勘探成果表明,南海北部到东海南部的广阔海域普遍发育中生代地层,但是除了在台西南盆地发现工业油气藏之外,其他地区的中生界尚未有大的勘探突破。本次研究将中生代南海北部—东海南部作为一个整体,开展大地构造背景分析,厘清各构造时期盆地的性质及其形成演化机制,探讨油气资源潜力。结果表明:南海北部—东海南部从晚三叠世到白垩纪整体为一个大型盆地,盆地的演化受其周围板块相互运动所控制;晚三叠世(T₃)主要受特提斯构造域控制,发育被动陆缘边缘海沉积盆地;从早侏罗世(J₁)到早白垩世均受古太平洋板块(伊泽奈崎板块)向欧亚板块俯冲机制的控制,其中早—中侏罗世(J_1-2)发育弧前坳陷盆地,晚侏罗—早白垩世(J₃—K₁)盆地性质为弧后断陷盆地;晚白垩世(K₂)受太平洋板块、欧亚板块和印度板块的联合控制,性质依然为弧后断陷盆地,与前期相比,裂陷强度加大;海水由东南方向侵入,地层垂向上由海相向陆相逐渐过渡,由东南向西北和东北方向,水体逐渐变浅,亦由海相向陆相逐渐演变;中生界在南海北部潮汕坳陷等地区发育深海相和海湾相泥岩,在东海南部基隆坳陷也发育良好的海湾相泥岩,生烃潜力大,具有形成大型油气藏的物质基础和地质条件,勘探潜力巨大。本次研究结果可以为南海北部—东海南部中生界的油气资源勘探提供依据。     

Sedimentary provenance of the Hengyang and Mayang basins,SE China,and implications for the Mesozoic topographic change in South China Craton: Evidence from detrital zircon geochronology

Detrital zircon U–Pb data from sedimentary rocks in the Hengyang and Mayang basins, SE China reveal a change in basin provenance during or after Early Cretaceous. The results imply a provenance of the sediment from the North China Craton and Dabie Orogen for the Upper Triassic to Middle Jurassic sandstones and from the Indosinian granitic plutons in the South China Craton for the Lower Cretaceous sandstones. The 90–120 Ma age group in the Upper Cretaceous sandstones in the Hengyang Basin is correlated with Cretaceous volcanism along the southeastern margin of South China, suggesting a coastal mountain belt have existed during the Late Cretaceous. The sediment provenance of the basins and topographic evolution revealed by the geochronological data in this study are consistent with a Mesozoic tectonic setting from Early Mesozoic intra-continental compression through late Mesozoic Pacific Plate subduction in SE China.     

Mesozoic tectonic evolution of the southwest continental Iberian Margin

An extensional event affected the southwest Margin of Iberia during Late Triassic to Early Cretaceous times, giving place to the Algarve basin. This basin was subjected to tectonic instability and it became infilled with siliciclastic and carbonate sequences with abundant interspersed volcanic rocks. Normal and strike-slip faults accommodated the deformation in the Algarve basin. The presence of a single flat or listric detachment surface is inferred from the study of hanging-wall structures. The dynamic and kinematic analyses of fault systems in the Spanish exposure of the Algarve basin allow us to establish three extensional phases. 1) A Late Triassic to Hettangian NE-SW directed extension associated with the initial breaking of Pangea and the opening of the Tethys in the eastern Mediterranean. 2) NW-SE extension from the Sinemurian to the Callovian, interpreted as a result of the activity as a sinistral fault of the Azores-Gibraltar transform boundary. 3) Finally, E-W extension during the Late Jurassic and Cretaceous, related to the North Atlantic rifting process.     

非洲Muglad多旋回陆内被动裂谷盆地演化及其控油气作用

非洲Muglad盆地经历多旋回陆内被动裂谷发育与叠合演化历史,具有不同于主动裂谷盆地、单旋回被动裂谷盆地以及跨越多个变革期的叠合盆地的演化特征。本文采用叠合盆地研究思路与方法,通过盆地演化过程中关键构造事件识别、盆地演化阶段划分,恢复和重建了各阶段原型盆地;基于不同期次裂谷作用发育程度、叠加过程及叠加方式的时空差异性,划分了不同凹陷的叠合类型,建立了不同叠合类型凹陷油气成藏模式。研究结果表明,受冈瓦纳大陆裂解、非洲大陆周缘大西洋、印度洋、红海张裂等构造事件的影响,该盆地经历了早白垩世Abu Gabra组(简称AG组,下同)沉积期、晚白垩世Darfur群沉积期以及新生代Nayil-Tendi组沉积期三大同裂谷作用阶段。早白垩世盆地原型为多个地堑及半地堑分隔式分布,为与大西洋张开有关的伸展应力场作用产物;晚白垩世Darfur群沉积时期盆地原型为地堑及半地堑继承发育,但沉积中心东移,为与印度洋张开有关的伸展应力场作用产物;新生代Nayil-Tendi组沉积时期原型盆地主要为发育在Kaikang坳陷的地堑、半地堑,为与红海张开有关的伸展应力场作用所致。依据三期裂谷作用在各凹陷的发育程度差异及构造沉降和沉积充填过程的不同,将各凹陷裂谷叠合方式划分为早断型、继承型与活动型三种类型。其中,早断型以Sufyan凹陷最为典型,其构造沉降与沉积充填具有"强-弱-更弱"特征;继承型以Fula凹陷最为典型,其构造沉降与沉积充填具有"强-较强-弱"特征,而活动型以Kaikang坳陷最为典型,其构造沉降与沉积充填具有"强-强-较强"的特征。三期裂谷作用在各凹陷内时空叠合差异控制了各凹陷油气成藏条件及富集规律的不同,早断型凹陷成藏组合以下部成藏组合为主,继承型则以中部成藏组合为主,而活动型凹陷则以上部成藏组合为主。这些多期叠加型被动裂谷盆地研究成果丰富了全球裂谷盆地构造特征与演化及其控油气作用的认识,深化了该类裂谷盆地油气分布规律研究,对于指导下一步勘探部署有重要借鉴意义。     

Structure and tectonic history of the foreland basins of southernmost South America

The common elements and differences of the neighboring Austral (Magallanes), Malvinas and South Malvinas (South Falkland) sedimentary basins are described and analyzed. The tectonic history of these basins involves Triassic to Jurassic crustal stretching, an ensuing Early Cretaceous thermal subsidence in the retroarc, followed by a Late Cretaceous–Paleogene compressional phase, and a Neogene to present-day deactivation of the fold–thrust belt dominated by wrench deformation. A concomitant Late Cretaceous onset of the foreland phase in the three basins and an integrated history during the Late Cretaceous–Cenozoic are proposed. The main lower Paleocene–lower Eocene initial foredeep depocenters were bounding the basement domain and are now deformed into the thin-skinned fold–thrust belts. A few extensional depocenters developed in the Austral and Malvinas basins during late Paleocene–early Eocene times due to a temporary extensional regime resulting from an acceleration in the separation rate between South America and Antarctica preceding the initial opening of the Drake Passage. These extensional depocenters were superimposed to the previous distal foredeep depocenter, postdating the initiation of the foredeep phase and the onset of compressional deformation. Another pervasive set of normal faults of Paleocene to Recent age that can be recognized throughout the basins are interpreted to be a consequence of flexural bending of the lithosphere, in agreement with a previous study from South Malvinas basin. Contractional deformation was replaced by transpressive kinematics during the Oligocene due to a major tectonic plate reorganization. Presently, while the South Malvinas basin is dominated by the transpressive uplift of its active margin with minor sediment supply, the westward basins undergo localized development of pull-apart depocenters and transpressional uplift of previous structures. The effective elastic thickness of the lithosphere for different sections of each basin is calculated using a dynamic finite element numerical model that simulates the lithospheric response to advancing tectonic load with active sedimentation.     

Meso–Cenozoic cooling and exhumation history of the Orlica‐Śnieżnik Dome (Sudetes,NE Bohemian Massif,Central Europe): Insights from apatite fission‐track thermochronometry

This study presents the first suite of apatite fission‐track (AFT) ages from the SE part of the Western Sudetes. AFT cooling ages from the Orlica‐?nie?nik Dome and the Upper Nysa K?odzka Graben range from Late Cretaceous (84 Ma) to Early Palaeocene–Middle Eocene (64–45 Ma). The first stage of basin evolution (~100–90 Ma) was marked by the formation of a local extensional depocentre and disruption of the Mesozoic planation surface. Subsequent far‐field convergence of European microplates resulted in Coniacian–Santonian (~89–83 Ma) thrust faulting. AFT data from both metamorphic basement and Mesozoic sedimentary cover indicate homogenous Late Cretaceous burial of the entire Western Sudetes. Thermal history modeling suggests that the onset of cooling could be constrained between 89 and 63 Ma with a climax during the Palaeocene–Middle Eocene basin inversion phase.     

Extension structural records in the Qinshui basin (North China) since the Late Mesozoic

Qinshui basin has abundant coal-bed methane resources and has been undergoing intensive intracontinental rifting and extensional tectonics since the Late Mesozoic. Some fractures, which were previously considered as conjugate shear fractures, are interpreted as joint sets with extension characteristics, for the first time in the Qinshui basin. The widely distributed joint sets with stable attitudes can be divided into four sets. This paper presents updated results of fault-slip datasets collected in different zones of the Qinshui basin and addresses the changes in the direction of extensional stresses since the Late Mesozoic. Based on the analysis results of the slickenline of normal faults, joint sets in the field, and focal mechanism solutions data from the Shanxi Province, we identified four main directions of extension since the Late Mesozoic in the Qinshui basin: (1) Early Cenozoic ENE–WSW (85 ± 15°) extension; (2) Palaeogene NNE–SSW (30 ± 5°) extension; (3) Miocene NW–SE (135 ± 15°) extension; and (4) Late Pliocene–quaternary NNW–SSE (170 ± 5°) extension. The principal extension directions in the Qinshui basin seem to have undergone a counterclockwise rotation from the Early Cenozoic to the Miocene. We prefer that the extension deformation events in the Qinshui basin since the Late Mesozoic were mainly related to the back-arc spreading induced by westward subduction of the paleo-Pacific plate under the Eurasian continent.     

大别山造山带与安徽沿江中新生代盆地的盆山耦合关系

安徽沿江中新生代盆地位于大别山造山带南缘，为先挤压、后伸展形成的叠合盆地，是探讨扬子板块陆内深俯冲—大别山造山带隆起与中、下扬子盆地沉降的耦合关系的理想场所。在早中生代，大别山为华南和华北大陆碰撞造山带，华南地壳向深处俯冲并承受超高压变质作用，超高压变质岩不断向上折返，沿江坳陷具有前陆盆地性质，盆地充填有晚三叠世—中侏罗世磨拉石层序；在晚中生代，在中国东部整体的拉张背景下，大别山变质带完全折返上隆，处于变质核杂岩隆升状态，而沿江坳陷具有裂陷盆地性质，充填有晚侏罗世—早白垩世、晚白垩世—古近纪两个红色碎屑构造层序，起因于地壳拆沉而产生的均衡隆升和伸展断陷的构造耦合。     

Quaternary tectonics in a passive margin: Marajó Island,northern Brazil

Marajó Island is located in a passive continental margin that evolved from rifting associated with the opening of the Equatorial South Atlantic Ocean in the Late Jurassic/Early Cretaceous period. This study, based on remote sensing integrated with sedimentology, as well as subsurface and seismographic data available from the literature, allows discussion of the significance of tectonics during the Quaternary history of marginal basins. Results show that eastern Marajó Island contains channels with evidence of tectonic control. Mapping of straight channels defined four main groups of lineaments (i.e. NNE–SSW, NE–SW, NW–SE and E–W) that parallel main normal and strike‐slip fault zones recorded for the Amazon region. Additionally, sedimentological studies of late Quaternary and Holocene deposits indicate numerous ductile and brittle structures within stratigraphic horizons bounded by undeformed strata, related to seismogenic deformation during or shortly after sediment deposition. This conclusion is consistent with subsurface Bouguer mapping suggestive of eastern Marajó Island being still part of the Marajó graben system, where important fault reactivation is recorded up to the Quaternary. Together with the recognition of several phases of fault reactivation, these data suggest that faults developed in association with rift basins might remain active in passive margins, imposing important control on development of depositional systems. Copyright © 2007 John Wiley & Sons, Ltd.     

渤海湾地区的中生代盆地构造概论

根据 1∶5 0万渤海湾新生代盆地区基岩地质图揭示的残留中生代地层的分布及构造变形特征 ,渤海湾地区的中生代盆地可以分为 5期。早—中三叠世、晚三叠世盆地为克拉通内部大型坳陷盆地 ,其中晚三叠世盆地仅分布在渤海湾西南部地区。早—中侏罗世盆地分布于印支运动形成的向斜坳陷核部 ,属于压陷挠曲型盆地。晚侏罗世—早白垩世盆地分布广泛 ,属于裂陷盆地 ;晚白垩世盆地属于后裂陷阶段的坳陷盆地。这些盆地受印支运动、燕山运动影响而发生反转。印支运动在渤海湾地区的东、西部的表现有明显差异。西部变形弱、以近EW向宽缓褶皱变形为主 ,东部变形强、并叠加了NE向褶皱和逆冲断层变形。早燕山运动使渤海湾地区形成宽缓的大型NE向褶皱变形 ,并使早—中侏罗世盆地发生反转和逆冲断层变形 ;中、晚燕山运动基本没有在渤海湾地区形成褶皱构造变形 ,而是表现为晚侏罗—早白垩世盆地和晚白垩世盆地的区域性反转隆升。下—中侏罗统沉积之后 ,渤海湾地区的构造格局发生基本变革 ,进入以裂陷盆地为主的构造演化时期。     

河套盆地吉兰泰凹陷中生代构造层划分及意义

2017年河套盆地临河坳陷油气勘探取得重要发现,基于区域中生代以来大地构造演化系统梳理,以钻井与地震对照、研究区与邻近盆地类比为研究方法,划分河套盆地临河坳陷南部吉兰泰凹陷中生代构造层,并绘制其分布范围,探讨其赋存特征与意义。结果表明：研究区中生界除三叠系外发育齐全,厚度巨大,且白垩系自上而下可细分为K1 ^I、K1 ^II和K1^III三个构造层;除K1I构造层全区广覆式发育外,其它构造层呈楔状—缓楔状,长轴沿主控断裂NNE向延伸;研究区自中生代以来盆地性质经历了早中侏罗世断陷、早白垩世早期断陷、早白垩世中期断拗转换和早白垩世晚期拗陷的演化过程;F ₃和F ₇断层之间的K1 ^II和K1 ^III构造层、F ₇断层东部的J构造层均具良好的油气勘探前景。     

Mesozoic tectonic evolution of the Southeast China Block: New insights from basin analysis

In order to better understand the Mesozoic tectonic evolution of Southeast China Block (SECB in short), this paper describes geological features of Mesozoic basins that are widely distributed in the SECB. The analyzed data are derived from a regional geological investigation on various Mesozoic basins and a recently compiled 1:1,500,000 geological map of Mesozoic–Cenozoic basins. Two types of basin are distinguished according to their tectonic settings, namely, the post-orogenic basin (Type I) and the intracontinental extensional basin (Type II); the latter includes the graben and the half-graben or faulted-depression basins. Our studies suggest that the formation of these basins connects with the evolution of geotectonics of the SECB. The post-orogenic basin (Type I) was formed in areas from the piedmont to the intraland during the interval from Late Triassic to Early Jurassic; and the formation of the intracontinental extensional basin (Type II) connects with an intracontinental crustal thinning setting in the Late Mesozoic. The graben basin was generated during the Middle Jurassic and is associated with a bimodal volcanic eruption; and the half-graben or faulted-depression basin, filled mainly by the rhyolite, tuff and sedimentary rocks during Early Cretaceous, is occupied by the Late Cretaceous–Paleogene red-colored terrestrial clastic rocks. We noticed that the modern outcrops of numerous granites and basins occur in a similar level, and the Mesozoic granitic bodies contact with the adjacent basins by large normal faults, suggesting that the modern landforms between granites and basins were yielded by the late crustal movement. The modern basin and range framework was settled down in the Cretaceous. Abundant sedimentary structures are found in the various basins, from that the deposited environments and paleo-currents are concluded; during the Late Triassic–Early Jurassic time, the source areas were situated to the north and northeast sides of the outcrop region. In this paper, we present the study results on one geological and geographical separating unit and two separating fault zones. The Wuyi orogenic belt is a Late Mesozoic paleo-geographically separating unit, the Ganjiang fault zone behaves as the western boundary of Early Cretaceous volcanic rocks, and the Zhenghe–Dapu fault zone separates the SE-China Coastal Late Mesozoic volcanic-sedimentary basins and the Wuyi orogenic belt. Finally, we discuss the geodynamic mechanisms forming various basins, proposing a three-stage model of the Mesozoic sedimentary evolution.     

东海盆地中、新生代盆架结构与构造演化

基于地貌、钻井、岩石测年和地震等资料,分析盆地地层分布、盆架结构、构造单元划分和裂陷迁移规律,结果表明东海盆地由台北坳陷、舟山隆起、浙东坳陷、钓鱼岛隆褶带和冲绳坳陷构成,是以新生代沉积为主、中生代沉积为辅的大型中、新生代叠合含油气盆地;古元古代变质岩系构成了盆地的基底。该盆地不仅是印度-太平洋前后相继的动力体系作用下形成的西太平洋沟-弧-盆构造体系域一部分,而且也是古亚洲洋动力体系作用下形成的古亚洲洋构造域和特提斯洋动力体系作用下形成的特提斯洋构造域一部分,晚侏罗世至早白垩世经历了构造体制转换,盆地格局发生重大变革,早白垩世以前主要受古亚洲-特提斯洋构造体制影响的强烈挤压造山和地壳增厚作用演变为早白垩世以来主要受太平洋构造体制控制的陆缘伸展裂陷和岩石圈减薄作用,经历侏罗纪古亚洲-特提斯构造体制大陆边缘拗陷和白垩纪以来太平洋构造体制弧后裂陷两大演化阶段。白垩纪以来太平洋构造体制的弧后裂陷演化阶段可细分为早白垩世至始新世裂陷期、渐新世至晚中新世拗陷期和中新世末至全新世裂陷期。