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1.
陆弧和弧前盆地是俯冲体系中具有密切联系的构造单元。中生代以来,华南受多期板块俯冲的控制,发育大规模岩浆岩带及海域广泛分布的弧前盆地。但陆域弧岩浆岩较少,海域又缺乏足够钻井,各时期陆弧的位置存在较大争议,同时,南海北部至东海一带弧前盆地也缺乏系统认识,因此,亟须新的研究思路深化对华南晚中生代俯冲体系和俯冲过程的认识。本文以前人研究为基础,对海域钻遇中生界的典型钻井进行了详细分析,系统开展了海域盆地区域构造和沉积对比,将弧前盆地发育与岛弧变迁相结合综合分析。结果表明早侏罗世—早白垩世陆弧位于南海北部—东海靠近陆域一侧,经历了早侏罗世局限陆弧、中晚侏罗世沿海陆弧带、早白垩世向海沟方向的迁移。在此过程中,华南海域弧前盆地群于中侏罗世正式形成,早白垩世发育盆缘角度不整合,粗碎屑相带向海沟方向迁移,晚白垩南海北部与东海各自进入新的构造体制,结束弧前盆地的发育。华南沿海海域中生代盆地的发育可为陆弧的展布提供重要约束,弧岩浆岩带的迁移控制了弧前盆地的演化。 相似文献
2.
Marco Cuffaro Federica Riguzzi Davide Scrocca Carlo Doglioni 《International Journal of Earth Sciences》2011,100(8):1915-1924
We performed geodetic strain rate analyses in southern Italy, using new GPS velocities. Two-dimensional strain and rotation
rate fields were estimated and results show that most of the shortening is distributed in the northern Sicily offshore. Extension
becomes more evident and comparable with shortening on the eastern side of the same margin, and greater in the eastern Sicily
offshore. Principal shortening and extension rate axes are consistent with long-term geological features: seismic reflection
profiles show both active compressive and extensional faults affecting Pleistocene strata. We show evidence for contemporaneous
extension and transtension in the Cefalù Basin. Combining geodetic data and geological features point to the coexistence of
independent geodynamic processes, i.e., the active E–W backarc spreading in the hangingwall of the Apennines subduction zone
and shortening along the southern margin of the Tyrrhenian backarc basin operated by the NNW-motion of Africa relative to
Eurasia. 相似文献
3.
The Etna volcano is located in an apparently anomalous position on the hinge zone of the Apennines subduction and its Na-alkaline geochemistry does not favour a magma source from the deep slab as indicated for the Aeolian K-alkaline magmatism. The steeper dip of the regional foreland monocline at the front of the Apennines in the Ionian Sea than in Sicily, implies a larger rollback of the subduction hinge in the Ionian Sea. Moreover, the lengthening of the Apennines arc needs extension parallel to the arc. Therefore, the larger southeastward subduction rollback of the Ionian lithosphere with respect to the Hyblean plateau in Sicily, should kinematically produce right-lateral transtension and a sort of vertical 'slab window' which might explain (i) the Plio-Pleistocene alkaline magmatism of eastern Sicily (e.g. the Etna volcano) and (ii) the late Pliocene to present right lateral transtensional tectonics and seismicity of eastern Sicily. The area of transfer of different dip and rollback occurs along the inherited Mesozoic passive continental margin between Sicily and the oceanic Ionian Sea, i.e. the Malta escarpment. 相似文献
4.
Deep-large faults in the central continental margin of eastern China are well developed. Based on the regularity of spatial
and temporal distribution of the faults, four fault systems were divided: the Yanshan orogenic belt fault system, the Qinling-Dabie-Sulu
orogenic belt fault system, the Tanlu fault system and the East China Sea shelf basin-Okinawa trough fault system. The four
fault systems exhibit different migration behaviors. The Yanshan orogenic belt fault system deflected from an EW to a NE direction,
then to a NNE direction during the Indo-Chinese epoch-Yanshanian epoch. The thrust-nappe strength of the Qinling-Dabie orogenic
belt fault system showed the tendency that the strength was greater in the south and east, but weaker in the north and west.
This fault system faulted in the east and folded in the west from the Indo-Chinese epoch to the early Yanshanian epoch. At
the same time, the faults also had a diachronous migration from east to west from the Indo-Chinese epoch to the early Yanshanian
epoch. On the contrary, the thrust-nappe strength was greater in the north and west, weaker in the south and east during the
late Yanshanian epoch-early Himalayan epoch. The Tanlu fault system caused the basin to migrate from west to east and south
to north. The migration regularity of the East China Sea shelf basin-Okinawa trough fault system shows that the formation
age became younger in the west. The four fault systems and their migration regularities were respectively the results of four
different geodynamic backgrounds. The Yanshan orogenic belt fault system derived from the intracontinental orogeny. The Qinling-Dabie-Sulu
orogenic belt fault system derived from the collision of plates and intracontinental subduction. The Tanlu fault system derived
from the strike-slip movement and the East China Sea shelf basin-Okinawa trough fault system derived from plate subduction
and retreat of the subduction belt.
Translated from Journal of Jilin University (Earth Science Edition), 2005, 35(5): 554–563 [译自: 吉林大学学报 (地球科学版)] 相似文献
5.
南秦岭山阳-柞水矿集区构造-岩浆-成矿作用 总被引：9，自引：2，他引：7
山阳-柞水矿集区是南秦岭成矿带主要矿集区之一。从新元古代到晚侏罗世-早白垩世,山阳-柞水地区经历了洋壳俯冲和陆陆碰撞的构造演化,在演化的不同阶段形成了不同矿化类型、矿化组合的Cu、PbZn、Ag、Fe、Mo、Au矿床。新元古代时期,由于洋壳的俯冲作用,山阳-柞水地区形成了与基性岩有关的钛磁铁矿;泥盆纪-二叠纪时期,古秦岭洋消减形成山阳-柞水弧前盆地的同时,也形成一系列沉积型Fe、Ag、PbZn矿床;三叠纪时期,华北、扬子板块全面碰撞并形成了与碰撞作用密切相关的晚三叠世斑岩型Mo矿和造山型Au矿;晚侏罗世-早白垩世时期,则形成了碰撞后伸展环境下的矽卡岩-斑岩型CuMo-Au矿床。山阳-柞水矿集区内的各种时代和类型的矿床是秦岭造山带不同阶段的构造-岩浆活动的产物,对真实、客观的理解秦岭地区的构造演化具有重要意义。 相似文献
6.
The Antarctic Ross Orogen was built up during the early Paleozoic in the framework of the convergence between the Paleo-Pacific oceanic plate and the Gondwana continental margin. Models for the Ross Orogen in northern Victoria Land are based on terranes having a variable provenance with respect to the margin. However, recent studies provide evidence for the occurrence of different pieces of the lithospheric puzzle: (i) the Wilson continental magmatic arc, representing the main part of the active Gondwana margin, (ii) the Bowers arc–backarc system, (iii) the Admiralty crustal ribbon including continental material of the Wilson forearc, and (iv) the newly discovered, Cambrian oceanic magmatic Tiger arc, along the Ross Sea coast. An updated model is presented in which, after the Early Cambrian magmatic activity of the Wilson arc, a retreat of the subduction zone in the Early–Middle Cambrian gave way to boudinage of the Wilson forearc, trenchward arc migration, opening of the Bowers backarc basin and inception of the outboard Tiger subduction zone. Renewed convergence resulted in the development of the Middle Cambrian Bowers arc, closure of the backarc and deep underthrusting of portions of it at the Middle–Late Cambrian. Finally, in the latest Cambrian to earliest Ordovician, fast exhumation was coupled in the north with erosion and sediment shed to the northeast, and with extension and potassic magmatism in central and southern Victoria Land. 相似文献
7.
The evolution of an active continental margin is simulated in two dimensions, using a finite difference thermomechanical code with half-staggered grid and marker-in-cell technique. The effect of mechanical properties, changing as a function of P and T, assigned to different crustal layers and mantle materials in the simple starting structure is discussed for a set of numerical models. For each model, representative P–T paths are displayed for selected markers. Both the intensity of subduction erosion and the size of the frontal accretionary wedge are strongly dependent on the rheology chosen for the overriding continental crust. Tectonically eroded upper and lower continental crust is carried down to form a broad orogenic wedge, intermingling with detached oceanic crust and sediments from the subducted plate and hydrated mantle material from the overriding plate. A small portion of the continental crust and trench sediments is carried further down into a narrow subduction channel, intermingling with oceanic crust and hydrated mantle material, and to some extent extruded to the rear of the orogenic wedge underplating the overriding continental crust. The exhumation rates for (ultra)high pressure rocks can exceed subduction and burial rates by a factor of 1.5–3, when forced return flow in the hanging wall portion of the self-organizing subduction channel is focused. The simulations suggest that a minimum rate of subduction is required for the formation of a subduction channel, because buoyancy forces may outweigh drag forces for slow subduction. For a weak upper continental crust, simulated by a high pore pressure coefficient in the brittle regime, the orogenic wedge and megascale melange reach a mid- to upper-crustal position within 10–20 Myr (after 400–600 km of subduction). For a strong upper crust, a continental lid persists over the entire time span covered by the simulation. The structural pattern is similar in all cases, with four zones from trench toward arc: (a) an accretionary complex of low-grade metamorphic sedimentary material; (b) a wedge of mainly continental crust, with medium-grade HP metamorphic overprint, wound up and stretched in a marble cake fashion to appear as nappes with alternating upper and lower crustal provenance, and minor oceanic or hydrated mantle interleaved material; (c) a megascale melange composed of high-pressure and ultrahigh-pressure metamorphic oceanic and continental crust, and hydrated mantle, all extruded from the subduction channel; (d) zone represents the upward tilted frontal part of the remaining upper plate lid in the case of a weak upper crust. The shape of the P–T paths and the time scales correspond to those typically recorded in orogenic belts. Comparison of the numerical results with the European Alps reveals some similarities in their gross structural and metamorphic pattern exposed after collision. A similar structure may be developed at depth beneath the forearc of the Andes, where the importance of subduction erosion is well documented, and where a strong upper crust forms a stable lid. 相似文献
8.
广西那坡盆地火山岩-碳酸盐岩混杂型滑塌堆积:特殊的弧前域构造指相标志及其大地构造意义 总被引：1，自引：1，他引：0
本文详细调查揭示,位于中越边境地区的那坡弧前盆地北部边缘发育17处滑塌堆积,有些表现为火山岩-碳酸盐岩块混杂型滑塌堆积,即由火山岩滑塌块体和碳酸盐岩滑塌块体无序堆积而成;有些只是具软沉积变形特征的薄层碳酸盐岩滑塌块体;还有些是砂屑灰岩滑塌块体与碳酸盐岩(或钙质)浊积岩组合以及单一的碳酸盐岩浊积岩或碳酸盐岩碎屑流。碳酸盐岩质块体流和碎屑流一般夹于大型或巨型滑塌块体间,而碳酸盐岩(或钙质)浊积岩和块状砂岩等一般发育于滑塌堆积的远端,有的覆盖于滑塌块体之上。无论是时代还是地球化学组成,滑塌堆积中的具枕状构造的火山岩块与盆地北侧富宁县架街一带的早-中三叠世弧火山岩完全一致。具软沉积变形特征的薄层碳酸盐滑塌岩块中发育有厚30cm左右的风暴沉积层,暗示这些滑塌岩块是发育于火山弧边缘的或其上的局部的碳酸盐岩台地(主要为潮坪-潟湖相)沉积。与全球不同造山带弧前盆地对比表明,这些滑塌堆积是一种发育于构造活动强烈的弧前盆地边缘的特殊的事件沉积,可作为识别弧前域大地构造相单元的普适性沉积标志,也可用以分析断定俯冲增生造山极性。本文对碳酸盐岩滑塌块体的原始层理和软沉积变形的滑塌褶皱轴面方位测量统计揭示火山弧斜坡大体向南西方向(232°~240°)倾斜,滑塌堆积远端浊积岩古水流测量与校正结果揭示沉积物搬运方向为南或南西向,这表明华南地块与北越地块之间的古特提斯分支洋盆在早三叠世期间是向北俯冲消化减的。 相似文献
9.
目前对珠江口盆地中生代以来的演化过程及其与沉积环境演变的响应关系尚缺乏系统性认识.基于珠江口盆地中-新生代岩浆活动、断陷结构样式及其改造、典型构造变形样式、沉积中心的转换等特征的对比分析,将盆地中-新生代的构造演化划分为4个阶段、7个期次：（1）中侏罗世-晚白垩世早期（～170～90 Ma）为古太平洋板块俯冲主控的陆缘岩浆弧-弧前盆地演化阶段;（2）晚白垩世-始新世中期（～90～43 Ma）为太平洋板块俯冲后撤背景下弧后周缘前陆/造山后塌陷-主动裂谷演化阶段;（3）始新世中期-中中新世（～43～10 Ma）为华南挤出-古南海俯冲拖曳主导的被动陆缘演化阶段;（4）晚中新世以来（～10～0 Ma）为菲律宾板块NWW向仰冲主导的挤压张扭演化阶段.～90 Ma、～43 Ma、～10 Ma分别实现了由安第斯型俯冲向西太平洋型俯冲、由主动裂谷向被动陆缘伸展、由被动陆缘伸展向挤压张扭的转换.在此过程中,伴随着古南海和南海的发育-消亡,新生代裂陷期沉积环境由东向西、由南向北逐渐海侵,裂后期由南向北阶段性差异沉降,由陆架浅水向陆坡深水转换,这使得珠一/三、珠二、珠四坳陷的石油地质条件具有显著的分带差异性... 相似文献
10.
Mesozoic rocks of the Baja California Peninsula form one of the most areally extensive, best-exposed, longest-lived (160 my), least-tectonized and least-metamorphosed convergent-margin basin complexes in the world. This convergent margin shows an evolutionary trend that may be typical of arc systems facing large ocean basins: a progression from highly extensional (phase 1) through mildly extensional (phase 2) to compressional (phase 3) strain regimes. This trend is largely due to the progressively decreasing age of lithosphere that is subducted, which causes a gradual decrease in slab dip angle (and concomitant increase in coupling between lower and upper plates), as well as progressive inboard migration of the arc axis.This paper emphasizes the usefulness of sedimentary and volcanic basin analysis for reconstructing the tectonic evolution of a convergent continental margin. Phase 1 consists of Late Triassic to Late Jurassic oceanic intra-arc to backarc basins that were isolated from continental sediment sources. New, progressively widening basins were created by arc rifting and sea floor spreading, and these were largely filled with progradational backarc arc-apron deposits that record the growth of adjacent volcanoes up to and above sea level. Inboard migration of the backarc spreading center ultimately results in renewed arc rifting, producing an influx of silicic pyroclastics to the backarc basin. Rifting succeeds in conversion of the active backarc basin into a remnant backarc basin, which is blanketed by epiclastic sands.Phase 1 oceanic arc–backarc terranes were amalgamated by Late Jurassic sinistral strike slip faults. They form the forearc substrate for phase 2, indicating inboard migration of the arc axis due to decrease in slab dip. Phase 2 consists of Early Cretaceous extensional fringing arc basins adjacent to a continent. Phase 2 forearc basins consist of grabens that stepped downward toward the trench, filled with coarse-grained slope apron deposits. Phase 2 intra-arc basins show a cycle of (1) arc extension, characterized by intermediate to silicic explosive and effusive volcanism, culminating in caldera-forming silicic ignimbrite eruptions, followed by (2) arc rifting, characterized by widespread dike swarms and extensive mafic lavas and hyaloclastites. This extensional-rifting cycle was followed by mid-Cretaceous backarc basin closure and thrusting of the fringing arc beneath the edge of the continent, caused by a decrease in slab dip as well as a possible increase in convergence rate.Phase 2 fringing arc terranes form the substrate for phase 3, which consists of a Late Cretaceous high-standing, compressional continental arc that migrated inboard with time. Strongly coupled subduction resulted in accretion of blueschist metamorphic rocks, with development of a broad residual forearc basin behind the growing accretionary wedge, and development of extensional forearc (trench–slope) basins atop the gravitationally collapsing accretionary wedge. Inboard of this, ongoing phase 3 strongly coupled subduction, together with oblique convergence, resulted in development of forearc strike-slip basins upon arc basement.The modern Earth is strongly biased toward long-lived arc–trench systems, which are compressional; therefore, evolutionary models for convergent margins must be constructed from well-preserved ancient examples like Baja California. This convergent margin is typical of many others, where the early to middle stages of convergence (phases 1 and 2) create nonsubductable arc–ophiolite terranes (and their basin fills) in the upper plate. These become accreted to the continental margin in the late stage of convergence (phase 3), resulting in significant continental growth. 相似文献
11.
The southernmost sector of the Italian peninsula is crossed by an almost continuous seismogenic belt capable of producing
M ∼ 7 earthquakes and extending from the Calabrian Arc, through the Messina Straits, as far as Southeastern Sicily. Though
large earthquakes occurring in this region during the last millennium are fairly well known from the historical point of view
and seismic catalogues may be considered complete for destructive and badly damaging events (IX ≤ I
o ≤ XI MCS), the knowledge and seismic completeness of moderate earthquakes can be improved by investigating other kinds of
documentary sources not explored by the classical seismological tradition. In this paper, we present a case study explanatory
of the problem, regarding the Ionian coast between the Messina Straits and Mount Etna volcano, an area of North-eastern Sicily
lacking evidence of relevant seismic activity in historical times. Now, after a systematic analysis of the 18th century journalistic
sources (gazettes), this gap can be partly filled by the rediscovery of a seismic sequence that took place in 1780. According
to the available catalogues, the only event on record for this year is a minor shock (I
o = VI MCS, M
w = 4.8) recorded in Messina on March 28, 1780. The newly discovered data allow to reinstate it as the mainshock (I
o = VII–VIII MCS, M
w = 5.6) of a significant seismic period, which went on from March to June 1780, causing severe damage along the Ionian coast
of North-eastern Sicily. The source responsible for this event appears located offshore, 40-km south of the previous determination,
and is consistent with the Taormina Fault suggested by the geological literature, developing in the low seismic rate zone
at the southernmost termination of the 1908 Messina earthquake fault. 相似文献
12.
An active oceanic spreading ridge is being subducted beneath the South American continent at the Chile Triple Junction. This process has played a major part in the evolution of most of the continental margins that border the Pacific Ocean basin. A combination of high resolution swath bathymetric maps, seismic reflection profiles and drillhole and core data from five sites drilled during Ocean Drilling Program (ODP) Leg 141 provide important data that define the tectonic, structural and stratigraphic effects of this modern example of spreading ridge subduction.A change from subduction accretion to subduction erosion occurs along-strike of the South American forearc. This change is prominently expressed by normal faulting, forearc subsidence, oversteepening of topographic slopes and intensive sedimentary mass wasting, overprinted on older signatures of sediment accretion, overthrusting and uplift processes in the forearc. Data from drill sites north of the triple junction (Sites 859–861) show that after an important phase of forearc building in the early to late Pliocene, subduction accretion had ceased in the late Pliocene. Since that time sediment on the downgoing oceanic Nazca plate has been subducted. Site 863 was drilled into the forearc in the immediate vicinity of the triple junction above the subducted spreading ridge axis. Here, thick and intensely folded and faulted trench slope sediments of Pleistocene age are currently involved in the frontal deformation of the forearc. Early faults with thrust and reverse kinematics are overprinted by later normal faults.The Chile Triple Junction is also the site of apparent ophiolite emplacement into the South American forearc. Drilling at Site 862 on the Taitao Ridge revealed an offshore volcanic sequence of Plio-Pleistocene age associated with the Taitao Fracture Zone, adjacent to exposures of the Pliocene-aged Taitao ophiolite onshore. Despite the large-scale loss of material from the forearc at the triple junction, ophiolite emplacement produces a large topographic promontory in the forearc immediately after ridge subduction, and represents the first stage of forearc rebuilding. 相似文献
13.
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
14.
文章评述了增生造山作用的研究历史和进展,认为增生造山作用贯穿地球历史,是大陆增生的重要方式。用大陆边缘多岛弧盆系构造理解造山带的形成演化,提出巨型造山系的形成与长期发育的大洋岩石圈俯冲制约的两侧或一侧的多岛弧盆系密切相关。在多岛弧盆系演化过程中的弧 弧和弧 陆碰撞,弧前和弧后洋盆的消减冲杂岩的增生,洋底高原、洋岛/海山、外来地块(体)拼贴等一系列碰撞和增生造山作用形成大陆边缘增生造山系。大洋岩石圈最终消亡形成对接消减带,大洋岩石圈两侧的多岛弧盆系转化的造山系对接形成造山系的联合体。拼接完成后往往要继续发生大陆之间的陆 陆碰撞造山作用、陆内汇聚(伸展)作用,后者叠加在增生造山系上,使造山过程更加复杂。对接消减带是认识造山系形成演化的关键。大洋两侧多岛弧盆系经历的各种造山过程可以从广义上理解为一个增生造山过程。多岛弧盆系研究对于划分造山带细结构非常重要,是理解造山系物质组成、结构和构造的基础,并制约了造山后陆内构造演化。大陆碰撞前大洋两侧多岛弧盆系及陆缘系统更完整地记录了威尔逊旋回,记录的信息更加丰富。根据多岛弧盆系的思路对特提斯大洋演化提出新的模式,认为西藏冈底斯带自石炭纪以来受到特提斯大洋俯冲制约,三叠纪发生向洋增生造山作用,特提斯大洋于早白垩世末最终消亡。 相似文献
15.
The Late Mesozoic is an important tectonic period for subduction of Paleo-Pacific slab beneath East Asia continent. It intensely led to Jurassic to Cretaceous magmatism associated with intracontinental deformation in South China. Subduction-related accretionary complexes remained regionally from SW Japan, E Taiwan to the W Philippines and Borneo. Studies on geology in South China, especially in magmatism, have been performed with good data, results, and sufficient understandings; whereas those arc-related intermediate igneous rocks have been less found. The areas from East to South China Seas which are located at the junction between sea and land will be the preferred areas for the study of the Late Mesozoic magmatic arc and the forearc basin. The relevant arc-related magmatic rocks and forearc sedimentary records have been increasingly discovered. Studies of magmatic arc and forearc basin combined with subdction complex will be essential to the reconstruction of the convergent continental margin in South China. Analyses of magmatic arc identification from South to East China Seas, arc to forearc relationship, and assembly between arc and regional faults will become necessary to improve the knowledge of the model of East Asia convergent continental margin, and as well help to develop the understanding of Late Mesozoic forearc basin and resource potentials in the southeast sea areas. 相似文献
16.
DMITRIENKO Liudmila V. WANG Pengcheng LI Sanzhong CAO Xianzhi Ian SOMERVILLE ZHOU Zaizheng HU Mengying SUO Yanhui GUO Lingli WANG Yongming LI Xiyao LIU Xin YU Shengyao ZHU Junjiang 《《地质学报》英文版》2018,92(2):814-849
The East Asian geological setting has a long duration related to the superconvergence of the Paleo‐Asian, Tethyan and Paleo‐Pacific tectonic domains. The Triassic Indosinian Movement contributed to an unified passive continental margin in East Asia. The later ophiolites and I‐type granites associated with subduction of the Paleo‐Pacific Plate in the Late Triassic, suggest a transition from passive to active continental margins. With the presence of the ongoing westward migration of the Paleo‐Pacific Subduction Zone, the sinistral transpressional stress field could play an important role in the intraplate deformation in East Asia during the Late Triassic to Middle Jurassic, being characterized by the transition from the E‐W‐trending structural system controlled by the Tethys and Paleo‐Asian oceans to the NE‐trending structural system caused by the Paleo‐Pacific Ocean subduction. The continuously westward migration of the subduction zones resulted in the transpressional stress field in East Asia marked by the emergence of the Eastern North China Plateau and the formation of the Andean‐type active continental margin from late Late Jurassic to Early Cretaceous (160‐135 Ma), accompanied by the development of a small amount of adakites. In the Late Cretaceous (135‐90 Ma), due to the eastward retreat of the Paleo‐Pacific Subduction Zone, the regional stress field was replaced from sinistral transpression to transtension. Since a large amount of late‐stage adakites and metamorphic core complexes developed, the Andean‐type active continental margin was destroyed and the Eastern North China Plateau started to collapse. In the Late Cretaceous, the extension in East Asia gradually decreased the eastward retreat of the Paleo‐Pacific subduction zones. Futhermore, a significant topographic inversion had taken place during the Cenozoic that resulted from a rapid uplift of the Tibet Plateau resulting from the India‐Eurasian collision and the formation of the Bohai Bay Basin and other basins in the East Asian continental margin. The inversion caused a remarkable eastward migration of deformation, basin formation and magmatism. Meanwhile, the basins that mainly developed in the Paleogene resulted in a three‐step topography which typically appears to drop eastward in altitude. In the Neogene, the basins underwent a rapid subsidence in some depressions after basin‐controlled faulting, as well as the intracontinental extensional events in East Asia, and are likely to be a contribution to the uplift of the Tibetan Plateau. 相似文献
17.
南秦岭横丹浊积岩系是一套巨厚的浊流沉积,以向南或南东倾的单斜构造产出。由下而上,该沉积层序包括深水盆地、深水浊积扇和斜坡水道3个相序。相应地,沉积物粒度变粗,厚度变大,火山质组分含量增加,凝灰层大量发育,表明横丹浊积岩系为活动型浊积岩;其古水流方向为NNW—NNE向,物源区为南侧的碧口火山岩系。另外,横丹浊积岩系内还见石英岩、重结晶大理岩成分的砾石,说明其物源还包括被动陆缘环境的沉积物。相序、组构、沉积特征和物源区综合分析表明,横丹浊积岩系为弧前盆地充填物。构筑这一弧前盆地的动力学机制是洋壳板块向南俯冲于扬子板块被动陆缘之下,时代可能晚于中晚泥盆世。 相似文献
18.
The bathymetry and abrupt changes in earthquake seismicity around the eastern end of the Java Trench suggest it is now blocked south–east of Sumba by the Australian, Jurassic-rifted, continental margin forming the largely submarine Roti–Savu Ridge. Plate reconstructions have demonstrated that from at least 45 Ma the Java Trench continued far to the east of Sumba. From about 12 Ma the eastern part of the Java Trench (called Banda Trench) continued as the active plate boundary, located between what was to become Timor Island, then part of the Australian proximal continental slope, and the Banda Volcanic Arc. This Banda Trench began to be obliterated by continental margin-arc collision between about 3.5 and 2 Ma.The present position of the defunct Banda Trench can be located by use of plate reconstructions, earthquake seismology, deep reflection seismology, DSDP 262 results and geological mapping as being buried under the para-autochthon below the foothills of southern Timor. Locating the former trench guides the location of the apparently missing large southern part of the Banda forearc that was carried over the Australian continental margin during the final stage of the period of subduction of that continental margin that lasted from about 12 Ma to about 3.5 Ma.Tectonic collision is defined and distinguished from subduction and rollback. Collision in the southern part of the Banda Arc was initiated when the overriding forearc basement of the upper plate reached the proximal part of the Australian continental slope of the lower plate, and subduction stopped. Collision is characterised by fold and thrust deformation associated with the development of structurally high decollements. This collision deformed the basement and cover of the forearc accretionary prism of the upper plate with part of the unsubducted Australian cover rock sequences from the lower plate. Together with parts of the forearc basement they now form the exposed Banda orogen. The conversion of the northern flank of the Timor Trough from being the distal part of the Banda forearc accretionary prism, carried over the Australian continental margin, into a foreland basin was initiated by the cessation of subduction and simultaneous onset of collisional tectonics.This reinterpretation of the locked eastern end of the Java Trench proposes that, from its termination south of Sumba to at least as far east as Timor, and probably far beyond, the Java-Banda Trench and forearc overrode the subducting Australian proximal continental slope, locally to within 60 km of the shelf break. Part of the proximal forearc's accretionary prism together with part of the proximal continental slope cover sequence were detached and thrust northwards over the Java-Banda Trench and forearc by up to 80 km along the southwards dipping Savu Thrust and Wetar Suture. These reinterpretations explain the present absence of any discernible subduction ocean trench in the southern Banda Arc and the narrowness of the forearc, reduced to 30 km at Atauro, north of East Timor. 相似文献
19.
台湾造山带是中新世晚期以来相邻菲律宾海板块往北西方向移动,导致北吕宋岛弧系统及弧前增生楔与欧亚大陆边缘斜碰撞形成的。目前该造山带仍在活动,虽然规模很小,但形成了多数大型碰撞造山带中的所有构造单元,是研究年轻造山系统的理想野外实验室,为理解西太平洋弧-陆碰撞过程和边缘海演化提供了一个独特的窗口。本文总结了二十一世纪以来对台湾造山带的诸多研究进展,讨论了其构造单元划分及演化过程。我们将台湾造山带重新划分为6个构造单元,由西至东分依次为:(1)西部前陆盆地;(2)中央山脉褶皱逆冲带;(3)太鲁阁带;(4)玉里-利吉蛇绿混杂岩带;(5)纵谷磨拉石盆地;(6)海岸山脉岛弧系统。其中,西部前陆盆地为6.5Ma以来伴随台湾造山带的隆升剥蚀形成沉积盆地。中央山脉褶皱逆冲带为新生代(57~5.3Ma)欧亚大陆东缘伸展盆地沉积物由于弧-陆碰撞受褶皱、逆冲及变质作用改造形成的。太鲁阁带是造山带中的古老陆块,主要记录中生代古太平洋俯冲在欧亚大陆活动边缘形成的岩浆、沉积和变质岩作用。玉里-利吉蛇绿混杂岩带和海岸山脉岛弧系统分别为中新世中期(~18Ma)以来南中国海板块向菲律宾海板块之下俯冲形成的岛弧和弧前增生楔,其中玉里混杂岩中有典型低温高压变质作用记录,变质年龄为11~9Ma;岛弧火山作用的主要时限为9.2~4.2Ma。纵谷磨拉石盆地记录1.1Ma以来的山间盆地沉积。台湾造山带的构造演化可划分为4个阶段:(a)古太平洋板块俯冲与欧亚大陆边缘增生阶段(200~60Ma);(b)欧亚大陆东缘伸展和南中国海扩张阶段(60~18Ma);(c)南中国海俯冲阶段(18~4Ma);(d)弧-陆碰撞阶段(<6Ma)。台湾弧-陆碰撞造山带是一个特殊案例,其弧-陆碰撞并不伴随着弧-陆之间的洋盆消亡,而是由于北吕宋岛弧及弧前增生楔伴随菲律宾海板块运动向西北方走滑,仰冲到欧亚大陆边缘,形成现今的台湾造山带。 相似文献
20.
《International Geology Review》2012,54(4):468-481
The Neogene–Quaternary Siderno Basin is located in the southern Calabrian Arc, along an E–W transect including the Ionian side and part of the Tyrrhenian margin. The orogenic belt was generated by ongoing northward subduction of Ionian oceanic lithosphere beginning in the Early Cretaceous. Since the Oligocene, the area has experienced complex tectonics, including NW–SE-oriented pull-apart basins. The forearc region contains >2000 m of Oligocene-to-Quaternary strata that cover pre-Tertiary rocks. The succession forms an E-dipping monocline, with tectonic growth structures increasing upward. Erosional truncations and thickness variations suggest a different evolution for the Siderno Basin, which in comparison with northern and southern parts of the Ionian accretionary wedge, evolved differently during the Serravallian–Tortonian stages. NW–SE and NE–SW fault systems are dominant, the first exhibiting strike–slip and normal kinematics in the Nicotera–Gioiosa and Molochio–Antonimina fault zones. These structures were active during infilling of the Neogene basin, and represent a complex transfer zone. The NE–SW system shows two types of tectonic kinematics: (1) a compressive stage, with NW–SE-orientated shortening, responsible for inversion tectonics documented by east-verging folds, thrusts, and back-thrusts, and (2) emplacement of the variegated clay during the Langhian, which is related to back-thrust propagation. The strike–slip accommodated stress generated in the accretionary prism in response to subduction of Ionian lithosphere and progradation of the accretionary front of the Calabrian forearc. 相似文献