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1.
本篇讨论大陆岩石圈拆沉、伸展与裂解作用过程。由于大陆岩石圈厚度大而且很不均匀,产生裂谷的机制比较复杂。大陆碰撞远程效应的触发,岩石圈拆沉,以及板块运动的不规则性和地球应力场方向转折,都可能产生岩石圈断裂和大陆裂谷。岩石圈拆沉为在重力作用下"去陆根"的作用过程,演化过程可分为大陆根拆离、地壳伸展和岩石圈地幔整体破裂三个阶段。大陆碰撞带、俯冲的大陆和大洋板块、克拉通区域岩石圈,都可能产生岩石圈拆沉。大陆岩石圈调查表明,拉张区可见地壳伸展、岩石圈拆离、软流圈上拱和热沉降;它们是大陆岩石圈伸展与裂解早期的主要表现。从初始拉张的盆岭省到成熟的张裂省,拆离后地壳伸展成复式地堑,下地壳幔源玄武岩浆侵位,断裂带贯通并切穿整个岩石圈,表明地壳伸展进入成熟阶段。中国东北松辽盆地和西欧北海盆地曾处于成熟的张裂省。岩石圈破裂为岩浆侵位提供了阻力很小的通道网。岩浆侵位作用伴随岩石圈破裂和热流体上涌,成熟的张裂省可发展成大陆裂谷。多数的大陆裂谷带并没有发展成威尔逊裂谷带和洋中脊,普通的大陆裂谷要演化为威尔逊裂谷带,必须有来自软流圈的长期和持续的热流和玄武质岩浆的供应。威尔逊裂谷带岩石圈地幔和软流圈为地震低速带,其根源可能与来自地幔底部的地幔热羽流有关。 相似文献
2.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(2):111-117
We investigate the seismic anisotropy signature of the continental rifting process. Several sources of anisotropy are considered: the lithospheric deformation, the asthenospheric flow, and the occurrence of oriented meltpockets in the asthenospheric mantle. Our results show that contrasted anisotropy patterns should be associated with the various conceptual models of rifting. Thus seismic anisotropy measurements may allow one to discriminate between these models. Anisotropy measurements in the Rio Grande, East-African and Rhine rifts suggest that these rifts formed by a transtensional deformation of the lithospheric mantle rather than by homogeneous extension of the lithosphere. Alignment of melt-lenses in the asthenospheric wedge may also account for a significant part of the seismic anisotropy recorded in the internal domains of these rifts. 相似文献
3.
高温高压微束衍射实验进展及其地学应用 总被引：6，自引：6，他引：6
同步辐射X射线微束衍射技术与静态高压装置(包括金刚石压砧设备和大腔体压力机设备)结合运用是研究高温高压下物质晶体结构、相变等的有效方法。金刚石压砧高温高压实验技术的发展体现在:在产生极端高温高压的同时,获得准确的实验温度压力值,采用充装气体传压介质等方法减小压力梯度,采用激光双面加温技术和改进激光光路以减小样品径向和轴向的温度梯度。大腔体压力机高温高压实验技术的发展主要表现在产生更高的实验压力,以及测试过程中使样品在一定幅度摆动以消除晶体生长和择优取向对衍射数据的影响。同步辐射X射线微束衍射技术的发展主要表现在更高亮度和更宽能量范围的同步辐射光源的使用、X射线聚焦技术的发展,以及角色散X射线衍射测试技术的进步。介绍了近年来高温高压微束衍射实验在地球科学领域所取得的一些最新进展,包括硅酸盐超钙钛矿的实验发现,铁的高温高压相变及熔融曲线、SiO2 超斯石英相变、橄榄石尖晶石相—超尖晶石相转变压力的精确测定等研究结果;认为硅酸盐超钙钛矿的进一步深入研究,水对地球深部矿物岩石力学性质及熔融行为的影响,高温高压下物质的化学反应性和地球深部元素的地球化学行为等,是今后高温高压实验研究的重要方向。 相似文献
4.
华北克拉通东部显生宙地幔演化 总被引：23，自引：9，他引：14
华北克拉通东部显生宙以来的地幔可以划分为3种类型:克拉通型地幔,大陆活动带型地幔和大陆裂谷型地幔。1 700 Ma—古生代末,地幔属于克拉通型:ε(Nd,t)值高于-5,为弱富集型;层圈相互作用以幔源的熔体和/或流体与古老的岩石圈地幔的作用为主,但规模较小,范围局部。100 Ma以前的中生代地幔属于“大陆活动带型”:ε(Nd,t)值低,在-5以下,为富集型;地幔中含有地壳的组分,层圈相互作用以下地壳与弱化的岩石圈地幔之间的作用为主;发生的时间为190~100 Ma,高峰期在130 Ma左右;发生的部位邻近莫霍面,导源的岩浆多为钙碱性系列,部位浅,活动范围广泛。100 Ma至新生代,地幔属于“大陆裂谷型”:为亏损型的软流圈地幔,ε(Nd,t)值高,几乎均为正值。层圈相互作用转变为软流圈岩石圈地幔之间的作用,转变的时间具有约40 Ma的过渡时期,前锋开始于100~109 Ma,导源的岩浆大致沿NWW和NEE向的大型断裂带分布。进一步证实了软流圈地幔上隆的不均匀性和主动性。 相似文献
5.
珠江口盆地位于太平洋俯冲的东部动力系统、印度-澳大利亚板块与欧亚碰撞或新特提斯洋俯冲的西部动力系统相互作用的中间地带,因此其构造成因及南海海盆打开机制一直存在争论;且构造对南海北部陆缘盆地群的油气成藏有何作用也不甚清晰。本专辑以珠江口盆地为例,特别是以阳江东凹为精细解剖区,结合中国东部新生代盆地的研究成果,展开了以下问题讨论:(1)珠江口盆地成盆机制:是单一裂陷、多幕伸展、单次伸展-走滑,还是多幕叠合走滑模式?(2)盆地的成盆机制与洼陷的生排烃、油气成藏相关性,尤其是古近系烃源岩的形成条件与资源潜力如何?不同幕次的构造转换对"源-汇"体系和油气成藏的控制作用等;(3)南海海盆的打开方式和动力学机制探讨:是印度-澳大利亚板块与欧亚板块碰撞有关的挤出-逃逸模式、太平洋板块俯冲有关的弧后伸展模式、深部构造有关的地幔柱模式、与古南海俯冲有关的俯冲拖曳模式,还是右行右阶拉分模式?(4)中国东部近海盆地共性探讨:珠江口盆地的成盆、成藏、成烃机制是否与渤海湾盆地、东海陆架盆地具有相似性?研究结果揭示,多期走滑拉分作用对珠江口盆地形成及其油气成藏具有重要意义,也影响了南海及其周边盆地群的裂解和洋盆打开过程,其动力来源主要是太平洋俯冲动力系统。 相似文献
6.
Late Mesozoic and Cenozoic rifting and its dynamic setting in Eastern China and adjacent areas 总被引：45，自引：0，他引：45
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. 相似文献
7.
Evolution of the eastern margin of Korea: Constraints on the opening of the East Sea (Japan Sea) 总被引：2，自引：2，他引：2
Han-Joon Kim Gwang Hoon Lee Hyeong-Tae Jou Hyun-Moo Cho Hai-Soo Yoo Gun-Tae Park Ji-Soo Kim 《Tectonophysics》2007,436(1-4):37-55
We interpreted marine seismic profiles in conjunction with swath bathymetric and magnetic data to investigate rifting to breakup processes at the eastern Korean margin that led to the separation of the southwestern Japan Arc. The eastern Korean margin is rimmed by fundamental elements of rift architecture comprising a seaward succession of a rift basin and an uplifted rift flank passing into the slope, typical of a passive continental margin. In the northern part, rifting occurred in the Korea Plateau that is a continental fragment extended and partially segmented from the Korean Peninsula. Two distinguished rift basins (Onnuri and Bandal Basins) in the Korea Plateau are bounded by major synthetic and smaller antithetic faults, creating wide and considerably symmetric profiles. The large-offset border fault zones of these basins have convex dip slopes and demonstrate a zig-zag arrangement along strike. In contrast, the southern margin is engraved along its length with a single narrow rift basin (Hupo Basin) that is an elongated asymmetric half-graben. Analysis of rift fault patterns suggests that rifting at the Korean margin was primarily controlled by normal faulting resulting from extension rather than strike-slip deformation. Two extension directions for rifting are recognized: the Onnuri and Hupo Basins were rifted in the east-west direction; the Bandal Basin in the east–west and northwest–southeast directions, suggesting two rift stages. We interpret that the east–west direction represents initial rifting at the inner margin; while the Japan Basin widened, rifting propagated southeastward repeatedly from the Japan Basin toward the Korean margin but could not penetrate the strong continental lithosphere of the Korean Shield and changed the direction to the south, resulting in east–west extension to create the rift basins at the Korean margin. The northwest–southeast direction probably represents the direction of rifting orthogonal to the inferred line of breakup along the base of the slope of the Korea Plateau; after breakup the southwestern Japan Arc separated in the southeast direction, indicating a response to tensional tectonics associated with the subduction of the Pacific Plate in the northwest direction. No significant volcanism was involved in initial rifting. In contrast, the inception of sea floor spreading documents a pronounced volcanic phase which appears to reflect asthenospheric upwelling as well as rift-induced convection particularly in the narrow southern margin. We suggest that structural and igneous evolution of the Korean margin, although it is in a back-arc setting, can be explained by the processes occurring at the passive continental margin with magmatism influenced by asthenospheric upwelling. 相似文献
8.
初论大陆环境斑岩铜矿 总被引：43，自引：1，他引：42
世界范围内大型-巨型斑岩铜矿多数产于岩浆弧（岛弧、陆缘弧）环境,含矿斑岩岩浆起源与大洋板块的俯冲作用有关。综合研究了与大洋板块俯冲无关、产于中国大陆环境的若干大型-巨型斑岩铜矿。研究发现,这些大陆环境的斑岩铜矿,虽然其基本地质特征与岩浆弧环境斑岩铜矿具有广泛的类似性,但其动力学背景、含矿斑岩性质、岩浆起源演化、金属富集过程及其构造控制机制却独具特色。这些大陆环境斑岩铜矿至少可产出于4类环境：晚碰撞走滑环境、后碰撞伸展环境、后造山伸展环境和非造山崩塌环境。大陆环境含矿斑岩以高钾质为特征,多具高钾钙碱性和钾玄质特征,通常显示埃达克岩地球化学亲和性。其岩浆通常起源于加厚的新生镁铁质下地壳或拆沉的古老下地壳。陆间碰撞期的地壳大规模增厚以及其后的软流圈上涌和岩石圈拆沉,是形成含矿岩浆的主导性机制。含矿岩浆的金属初始富集通常经历两阶段过程：（1）幔源物质直接供给金属阶段;（2）伴随含水、高氧逸度埃达克质岩浆演化金属富集阶段。在第一阶段,幔源物质主要通过两种形式供给金属：（1）以幔源组分为主的新生下地壳直接熔融;（2）拆沉下地壳熔融产生的埃达克质熔体与地幔岩石圈发生水/岩反应。在第二富集阶段,下地壳角闪榴辉岩熔融过程中角闪石大量分解产生富水的、高度氧化的埃达克质熔体,其分异演化使金属元素作为不相容元素得以在残浆中富集。大陆环境含矿斑岩的浅成侵位主要受大规模走滑断裂系统、切割造山带的断裂系统和基底线性断裂构造控制。与走滑断裂系统相伴发育的走滑拉分盆地、切割造山带的张性断裂与平行造山带的逆冲断裂带交汇部位以及不同方向的线性断裂构成的棋盘格子构造,常常控制斑岩岩浆-热液系统的空间定位。 相似文献
9.
中国近海海域发育了渤海湾、东海和南海等10多个新生代富油气沉积盆地,其发育演化过程及动力学背景的异同需要在统一的研究思路和方法下进行系统的总结.以海域盆地油气勘探开发中积累的丰富的地质地球物理资料为基础,详细解释和分析了渤海、东海和南海三大海域新生代盆地的构造地层格架,进一步明确了渤海湾盆地斜向拉分盆地的演化阶段,证实了区域走滑断裂体系对盆地发育的重要控制作用;在东海陆架盆地划分出弧后前陆盆地的演化阶段,认识到区域挤压作用对该盆地的演化过程的重要性;在南海北部深水区发现了大型拆离断层及其所控制的拆离盆地,提出大型拆离断层作用是地壳薄化、地幔剥露和陆缘深水盆地形成演化的主要机制.研究揭示出中国近海海域盆地新生代期间在经历了古新世-中始新世期间分布全区的均一断陷作用之后,从晚始新世开始进入到区域构造的差异性演化阶段,其中渤海湾盆地进入斜向走滑拉分阶段,并持续到渐新世末期,随后是中新世的热沉降和上新世以来的加速沉降过程;东海陆架盆地则进入长期的弧后前陆盆地演化阶段,直到上新世开始才进入区域性的沉降过程;而南海则持续伸展形成深水拆离盆地,并最终在渐新世初期（32 Ma）发生岩石圈裂解,南海洋盆开始扩张,陆缘则进入被动大陆边缘演化阶段.区域板块运动学分析表明,晚始新世发生的全球板块运动重组事件导致了中国近海海域盆地构造的差异性演化.该事件发生之前,中国东部处于欧亚板块和太平洋板块相互作用构建的"双板块"动力体制之下,太平洋板块的俯冲后退作用导致了陆缘弧后伸展,形成了广布中国东部大陆边缘的盆岭式断陷盆地系.该事件之后,中国大陆处于印度板块、欧亚板块、太平洋板块和菲律宾海板块等构建的"多板块体制"之下,印度-欧亚大陆的碰撞、太平洋板块俯冲方向的转变、古南海的俯冲碰撞、菲律宾海板块的楔入及其与太平洋板块向西运移俯冲等产生了更为复杂的板块运动过程和多期次的运动重组事件导致了中国海域盆地成因类型的多样性和构造演化过程的差异性.海域盆地是我国重要的油气生产基地,本文的研究不仅进一步深化了中国海域盆地的形成演化过程和动力机制的认识,而且对于该区的油气勘探和开发也具有重要的实际应用价值. 相似文献
10.
Closure and opening of oceans on time‐scales of a few hundred million years is a fundamental tectonic process on Earth, typically referred to as a “Wilson cycle”. Subduction of oceanic and continental crust leading up to and during continent–continent collision can refertilize and enrich the orogenic continental lithospheric mantle in heat‐producing elements. The resulting thermal anomaly weakens the lithosphere and, along with structural weaknesses (e.g. sutures), make this orogenic lithosphere more prone to rifting given an extensional stress field. Thermal modelling shows that anomalously hot lithosphere can focus asthenospheric upwellings over time‐scales of a few hundred million years. Processes related to closure of oceans thus provide a mechanism for later localization of rifting and an extensional driving force. 相似文献
11.
S. I. Turchenko 《Geology of Ore Deposits》2017,59(2):103-111
By the end of the Archean, the period of active volcanism, plutonism, accretion, and cratonization had been completed by the construction of stable continental plates. Afterward, cratons were subject to intense extension owing to mainly mantle diapirism and ascent of asthenospheric flows, which gave rise to the formation of ensialic intracratonic basins, whereas other linear troughs were expressed in the formation of continental rifts. Zones of continental rifting are characterized by a wide spectrum of mineral resources (Cu, Ni, PGE, Co, Ti, V, etc.) related to igneous complexes. This paper is focused on metallogeny of nickel-sulfide and PGE mineralization in the Fennoscandian Shield. The results of metallogenic analysis of Paleoproterozoic riftogenesis, along with the account of previous achievements, have shown that the aforementioned mineralization is related to three consecutive plume-tectonic pulses of mantle activization, which are expressed in (i) upwelling of the subcontinental mantle enriched in LREE, (ii) intrusion of mafic and ultramafic melts derived from enriched and depleted Archean mantle sources, and (iii) formation of low-sulfide Pt–Pd and Pt-bearing Cu–Ni sulfide deposits. 相似文献
12.
This review considers the magmatic processes in the Carpathian–Pannonian Region (CPR) from Early Miocene to Recent times, as well as the contemporaneous magmatism at its southern boundary in the Dinaride and Balkans regions. This geodynamic system was controlled by the Cretaceous to Neogene subduction and collision of Africa with Eurasia, especially by Adria that generated the Alps to the north, the Dinaride–Hellenide belt to the east and caused extrusion, collision and inversion tectonics in the CPR. This long-lived subduction system supplied the mantle lithosphere with various subduction components. The CPR contains magmatic rocks of highly diverse compositions (calc-alkaline, K-alkalic, ultrapotassic and Na-alkalic), all generated in response to complex post-collisional tectonic processes. These processes formed extensional basins in response to an interplay of compression and extension within two microplates: ALCAPA and Tisza–Dacia. Competition between the different tectonic processes at both local and regional scales caused variations in the associated magmatism, mainly as a result of extension and differences in the rheological properties and composition of the lithosphere. Extension led to disintegration of the microplates that finally developed into two basin systems: the Pannonian and Transylvanian basins. The southern border of the CPR is edged by the Adria microplate via Sava and Vardar zones that acted as regional transcurrent tectonic areas during Miocene–Recent times.Major, trace element and isotopic data of post-Early Miocene magmatic rocks from the CPR suggest that subduction components were preserved in the lithospheric mantle after the Cretaceous–Miocene subduction and were reactivated especially by extensional tectonic processes that allowed uprise of the asthenosphere. Changes in the composition of the mantle through time support geodynamic scenarios of post-collision and extension processes linked to the evolution of the main blocks and their boundary relations. Weak lithospheric blocks (i.e. ALCAPA and western Tisza) generated the Pannonian basin and the adjacent Styrian, Transdanubian and Z?rand basins which show high rates of vertical movement accompanied by a range of magmatic compositions. Strong lithospheric blocks (i.e. Dacia) were only marginally deformed, where strike–slip faulting was associated with magmatism and extension. At the boundary of Adria and Tisza–Dacia strike–slip tectonics and core complex extension were associated with small volume Miocene magmatism in narrow extensional sedimentary basins or granitoids in core-complex detachment systems along older suture zones (Sava and Vardar) accommodating the extension in the Pannonian basin and afterward Pliocene–Quaternary inversion. Magmas of various compositions appear to have acted as lubricants in a range of tectonic processes. 相似文献
13.
西秦岭地区东昆仑-秦岭断裂系晚新生代左旋走滑历史及其向东扩展 总被引：17，自引：1，他引：16
要通过在TM遥感图像解译和野外观测的基础上,描述了东昆仑断裂带东段活动形迹的组成和活动断层地貌特征,阐述了甘南高原西秦岭地区新近纪拉分盆地的沉积-构造特征,提出了该区东昆仑-秦岭断裂系晚新生代左旋走滑伸展-走滑挤压-走滑伸展的3个阶段的构造变形模式。指出,中新世晚期至上新世早期,东昆仑-秦岭断裂系以左旋走滑伸展活动为主,伴随着西秦岭地区拉分盆地的形成和超基性火山岩群的发育。这期左旋走滑伸展活动向东扩展导致了渭河盆地新近纪引张应力方向由早期的NE-SW向转变为晚期的NW—SE向。上新世晚期以来(约3．4Ma以前),东昆仑-秦岭断裂系以左旋走滑挤压活动为主,导致早期拉分盆地的轻微褶皱变形,走滑挤压活动主要集中在东昆仑东段玛沁-玛曲主断裂带上。该期构造变动持续到早更新世,它的向东扩展产生了广泛的地壳形变效应,包括青藏东缘岷山隆起带的快速崛起、华北地区汾-渭地堑系的形成和发展以及郯庐断裂带右旋走滑活动等。中、晚更新世时期,断裂系以走滑伸展变形为主,主要集中在东昆仑断裂带东段3个分支上,地块向东挤出伴随着顺时针旋转。 相似文献
14.
由克拉通、造山带、裂谷、边缘海洋壳和岛弧等5大岩石圈类型构成的中国大陆,由于不同类型岩石圈对应的动力学机制及其效应不同,岩石圈不同类型之间的连接带必定是不连续带,与大陆成矿作用有密切的联系。中国大陆已知的绝大多数金属矿床分布于岩石圈不连续和再活化不连续处,表明岩石圈不连续为大型矿床(矿集区)形成提供有利的运-储空间。中国大陆西北、中国东部和西南地区构造-岩浆-成矿事件序列对比表明,一个地区岩石圈的壳-幔岩石学结构、大规模成矿作用,取决于最强的、最后一次的岩浆作用,大规模成矿作用的发生起始于造山岩石圈根失稳、去根和大规模软流圈上涌时期,C型埃达克岩的出现是其标志之一。分布于中国内陆的扬子、鄂尔多斯、塔里木和准噶尔盆地等地表热流值低的“冷盆”,深部属于克拉通型岩石圈背景,在构造上往往为造山带的前陆盆地,克拉通型岩石圈构造上的稳定性决定了这些克拉通盆地不断被周围造山带吞食、掩埋、改造的格局,虽然在这些盆地内如今都已发现油气田,但在盆地外那些现今被造山带前缘逆冲体覆盖的区域,也应该是油气田产出的有利区域,即盆地外造山带花岗岩下依然是寻找油气田的重要远景区。分布于中国东部的平原区和黄海、东海及南海等陆缘海区,属于地表热流值高的“热盆”,这些盆地下对应的是裂谷型或洋壳型岩石圈,它们是在新生代时期中国东部沿海地区进入了新的构造演化阶段——大陆裂谷作用下形成的,以伴随广泛的玄武岩喷发为标志,对流地幔物质和热输入使盆地热流值升高成为“热盆”、大陆裂谷型岩石圈,乃至洋壳岩石圈(如南海中央海盆);伴随裂陷作用及伸展构造普遍发育的幔源玄武岩浆大量喷发,以及大量沉积物的快速沉积、埋藏有利于油气田的形成,其中的组分,如CO2气田中的CO2可能主要源于地幔。中国东部平原及边缘海区域是最具前景的油气田分布区之一。 相似文献
15.
应用通过营口—潍坊断裂带及相关新生代盆地的地震剖面,采用专业软件分别计算了潍北凹陷、青东凹陷、莱州湾凹陷、黄河口凹陷、渤中凹陷、渤东凹陷、辽中凹陷和辽东凹陷的伸展量及构造沉降量,表明虽然同受断裂带走滑和软流圈上涌控制,但不同区段新生代伸展作用方向、主要发生时间和强度都有差别。南段是南北方向伸展,伸展作用主要发生在古新-始新世孔店组—沙河街组三段沉积时期;中段渤中—辽东湾南部地区具有多向伸展特征,近东西方向和南北方向伸展作用最为强烈,主要伸展作用发生在中-晚始新世、渐新世和新近纪,特别是以新近纪强烈伸展作用区别于其它地区;北段即辽东湾中-北部地区主要是北西—南东方向伸展,主要伸展活动发生在中始新世沙河街组三段和渐新世东营组沉积时期。文章总结了4种不同类型的沉降,指出新生代的构造活动随时间有自南向北推移和自两侧向中间迁移的规律,提出不同方向断裂带的活化和新近纪北东东向新生构造的形成是裂陷强度向中间迁移并产生4种不同沉降类型盆地的原因。 相似文献
16.
前言右江盆地是指海西—印支期由师宗—弥勒断裂、红河断裂、紫云—南丹—河池断裂和灵山断裂所围限的滇黔桂地区。长期以来,由于该盆地所处的特殊构造背景、独特的岩相-构造格局和丰富的矿产资源,许多地质工作者都予以充分注意,对该盆地的性质提出了众多有益的观点和认识,除传统的槽、台、洼学说外,先后有“弧间盆地或弧后盆地”、“湘桂边缘海”、“弧后裂谷地槽”、“右江裂谷带”和“裂陷槽”等等。笔者参考了这些前人的工作成果,并据自己的研究,参与这一讨论,亦望同行指正。一、右江沉积盆地的性质笔者认为,右江海西—印支期沉积盆地应主要归属于古特提斯构造域,具有被动型裂谷盆地的沉积、构造、成矿与岩浆活动特点。 1.古特提斯于泥盆纪初沿金沙江-红河断裂带开裂。我国著名地质学家王鸿祯教授将扬子地台以西、松潘、甘孜三角地带以及巴颜喀拉地带称为古特提斯,并认为从泥盆—石炭纪 相似文献
17.
The Gondwana basins of peninsular India are traditionally considered as extensional-rift basins due to the overwhelming evidence
of fault-controlled synsedimentary subsidence. These basins indeed originated under a bulk extensional tectonic regime, due
to failure of the attenuated crust along pre-existing zones of weakness inherited from Precambrian structural fabrics. However,
disposition of the basins and their structural architecture indicate that the kinematics of all the basins cannot be extensional.
To maintain kinematic compatibility with other basins as well as the bulk lateral extension, some basins ought to be of strike-slip
origin. The disposition, shape and structural architecture of the Satpura basin, central India suggest that the basin could
be a pull-apart basin that developed above a releasing jog of a left-stepping strike-slip fault system defined by the Son-Narmada
south fault and Tapti north fault in consequence to sinistral displacement along WSW-ENE. Development of a sedimentary basin
under the above-mentioned kinematic condition was simulated in model experiments with sandpack. The shape, relative size,
stratigraphic and structural architecture of the experimental basin tally with that of the Satpura basin. The experimental
results also provide insights into the tectono-sedimentary evolution of the Satpura basin in particular and pull-apart basins
in general. 相似文献
18.
中国边缘海域及其邻区的岩石层结构与构造分析 总被引：3，自引：0，他引：3
利用中国边缘海域近年的地震层析成像结果,根据速度异常和各向异性分析东海、黄海和南海北部的岩石层结构和构造,讨论中朝块体和扬子块体在黄海内部的拼合边界(黄海东部断裂带)、东海陆架盆地上地幔异常与岩石层形成演化、南海北部地壳底部高速层的成因及地幔活动等问题。分析表明,黄海东部与朝鲜半岛之间存在一个深部构造界限(大致对应于黄海东部断裂带),分界两侧Pn波速度各向异性存在明显差异,反映不同构造应力和断裂剪切运动作用下的岩石层地幔变形特征。东海陆架下方的低速异常揭示了张裂盆地形成时期的地幔活动痕迹,表明中、新生代期间发生过地幔上涌并造成岩石层减薄,菲律宾海板块向西俯冲引发的地幔活动对东海陆架岩石层的形成、演化产生明显的影响。南海北部岩石层厚度较大并且温度相对偏低,地幔异常仅限于局部地区,估计南海北部大陆边缘的地壳底部高速层形成于张裂发生之前,或者是地壳形成时期壳幔分异时的产物。南海中央海盆的扩张不仅导致地壳拉张,软流层物质上涌,而且也造成岩石层地幔减薄甚至缺失。 相似文献
19.
陆缘扩张型地洼盆地系及其形成机制探讨 总被引：9，自引：5，他引：4
邹和平 《大地构造与成矿学》1995,19(4):303-313
本文提出“陆缘扩张型地洼盆地系”这一概念,以突出表述分布于东亚陆缘壳体之上,形成于地洼余动期的张性地洼盆地系列的壳体演化—动力环境。指出陆缘海中的裂陷盆地的成因难于与大洋板块俯冲导致弧后扩张的理论模式相联系,也不同于大西洋型盆地,而是大陆地壳演化到地洼余动期,并经历过华夏期地洼型造山运动之后拉伸裂陷的结果。论证了“岩石圈底层剥落、华夏期地洼造山带拉伸裂陷”是东亚陆缘扩张发生的一种重要机制,进而建立了由华夏期地洼型挤压造山带到盆岭型构造带和陆缘海盆地系的构造发展模式。 相似文献
20.
A geodynamic model for the formation and movement of marginal seas in the Pacific Ocean during lateral interaction between the Eurasian and Pacific lithospheric plates is proposed. In a transition strike-slip megazone, the continental and oceanic plates disintegrate into blocks, which are involved in rotation, thus causing formation of mantle plumes and tectonospheric funnels (ascending and descending lithospheric vortexes). The implications of the model are formulated. Three scenarios of the evolution of the marginal sea basins depending on the direction of motion of the Pacific plate are discussed. 相似文献