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1.
ZHENG Yanpeng LIU Baohua WU Jinlong LIANG Ruicai LIU Chenguang & ZHANG Zhengmin . Marine Geology College Ocean University of China Qingdao China . First Institute of Oceanography State Oceanic Administration Qingdao China . Key Laboratory of Marine Sedimentology Environmental Geology State Oceanic Administration Qingdao China 《中国科学D辑(英文版)》2005,48(8):1165-1174
The sea area east of Taiwan Island is a unique ac-tive arc-continental collision margin in China and even in the world with the NE-nearly EW extending Ryu-kyu trench-arc-backarc basin system on the east and the nearly N-S extending Manila trough and Luzon arc on the west. The sea area east of Taiwan Island differs from the Ryukyu trench-arc-basin system in structural property, but there is a certain genetic relation between the two (Fig. 1)[1-3]. Since the 1990s, many investigations and … 相似文献
2.
Some features of the arc-continent collision zone in the Ryukyu subduction system, Taiwan Junction area 总被引：1，自引：0，他引：1
Abstract To the northeast of Taiwan, northwestward subduction of the Philippine Sea plate is occurring beneath the Eurasian plate along the Ryukyu Trench. The Ryukyu Trench, which is well defined along the northeastern part of the Ryukyu arc, cannot be easily defined west of 123° east. This is an area where the Gagua Ridge (whose origin is controversial) enters the trench from the south. On the basis of the marine geophysical survey data the following results have been obtained. The structural elements associated with the Ryukyu subduction system deform and partially disappear west of 123° east. Among other things the Ryukyu Trench terminates close to the western slope of the Gagua Ridge. The Gagua Ridge is the result of tectonic heaping and is likely to be an uplifted sliver of oceanic crust. The interaction between the Ryukyu subduction system and the Taiwan collision zone encompasses a wide region from Taiwan to the longitude 124.5° east. The Gagua Ridge is a boundary between the active deformation zone related to the collision in Taiwan and the West Philippine Basin. It is proposed that there is a tectonic zone that can be traced from the Okinawa Trough on the north to the southern termination of the Gagua Ridge on the south. 相似文献
3.
渤海、黄海和东海等中国东部海域在地质构造上是大陆向海的自然延伸，海域内的构造方向与大陆一致，均为NNE-NE向，但属于不同的二级大地构造单元，渤海和北黄海属于华北地块，南黄海属于扬子地块，东海属于华南地块。由于各地块与现今活动板块边界位置不同，构造与地震活动性差异较大，渤海和北黄海地区地震活动主要受印度板块与欧亚板块碰撞形成的东喜马拉雅构造节远场效应影响，地震活动强烈；南黄海地区以中强地震活动为主；东海地区地震活动主要受菲律宾海板块与欧亚板块碰撞形成的琉球俯冲带影响。冲绳海槽是正在形成的（活动的）边缘海盆地，不仅有浅源地震，且有中源地震活动。东海陆架盆地由于受冲绳海槽扩张的影响，停止发育，构造与地震活动相对较弱。 相似文献
4.
利用最新的重磁数据对冲绳海槽南部的基底构造进行了推断解释，研究表明，在冲绳海槽南部，莫霍面构造为一南北两端高，中间低的鞍状构造，地壳厚度在15.5~21 km之间变化.基底深度一般在4~6 km之间变化，表现为南段深度大，北段深度小，在北西向断裂系的作用下，基底局部构造大都成北西向展布，说明冲绳海槽早期的北东向带状构造受到了后期的北西向构造活动的强烈改造作用.在冲绳海槽南部发育有两条沿北北东向展布的火成岩带，一条分布在冲绳海槽扩张轴以东及琉球岛弧西侧下坡；另一条分布在冲绳海槽与琉球岛弧隆褶带的结合部位，火成岩主要是由北东向构造活动产生的，而与北西向断裂关系不密切. 相似文献
5.
本文通过面波层析成像得到了中国东部海域及邻近地区的地壳上地幔S波速度图像,给出了主要构造单元的区划及其结构特征,并讨论了速度结构与现今构造活动及构造演化历史的关系.研究区内中下地壳的平均速度与地震活动存在比较显著的关系,强震基本都发生在低速区内或高低速过渡区.太行山以东地壳内存在几条北西向低速带,其中张家口—渤海地震带下方的低速带最为显著.东部海域划分成北黄海、南黄海、东海、和冲绳海槽等4个构造块体.北黄海具有较薄较高速的岩石圈,与南华北盆地类似,推测是中生代特提斯洋向北俯冲造成岩石圈减薄的遗迹.北华北地区具有低速的地壳和较厚的岩石圈,岩石圈地幔速度偏低且上下比较均匀,可能反映中生代沿北方缝合带持续碰撞作用的特点.南黄海具有相对较厚的岩石圈,较多地保存了下扬子克拉通的特征.在下扬子与华北地块的拼合过程中,洋壳俯冲可能是北黄海和苏皖地区上地幔低速特征的成因.在125°E以东的朝鲜半岛地区未发现这一拼合过程的遗迹.有可能整个朝鲜半岛都是华北地块的一部分;但也有可能是太平洋俯冲和日本海张开的作用完全改造了朝鲜半岛的岩石圈上地幔,抹去了以往构造运动的痕迹.东海地区的地壳厚度,特别是岩石圈厚度向冲绳海槽方向减小,反映出菲律宾海板块俯冲在弧后广大地区都有影响.冲绳海槽地区可见俯冲的菲律宾海板片以及板片上方显著低速的地壳和上地幔,为冲绳海槽的弧后扩张机制提供了证据. 相似文献
6.
冲绳板块位于菲律宾海板块向欧亚板块俯冲形成的西太平洋边缘活动带上,构造应力场图像及其动力学机制表现得相当复杂．采用伪三维有限元方法,以WSM2008 观测应力场数据的应力取向和应力型两方面指标作为主要约束,对冲绳板块构造应力场进行了数值模拟．通过对计算结果的分析,对模型涉及的各种作用力作出了估计．在此基础上,对冲绳板块岩石层的状态,以及该地区的板块动力学特征进行了探讨,并得到了以下一些初步认识:① 软流层静压推力控制着该地区构造应力场的基本形态;② 冲绳海槽的演化过程,例如该地区的岩石层减薄与其下地幔流的上升等,也在很大程度上影响了该地区的板内应力场空间分布特征;③ 琉球俯冲带边界力的作用是分段的,不同区段作用力对板内应力场的影响有所不同． 相似文献
7.
利用最新的重磁数据对冲绳海槽北部的基底构造进行了推断解释.研究表明，在海槽内部主要发育两条火山带，一条为著名的吐噶喇火山链，由一系列活动的或休眠的串珠状展布的活火山岛构成；另一条沿海槽中央张裂轴分布，主要由孤立的海底火山构成.冲绳海槽的基底具有沿东西向凹－凸－凹相间的构造格局，深度在1 km~8 km之间变化，受吐葛喇断裂带的北部断裂F1的作用，第三系基底构造发生了显著变化，说明吐葛喇断裂带的北部断裂F1是一条构造转换带.莫霍面为一北北东向的向东倾伏的幔坡，地壳厚度由21 km减至18 km. 相似文献
8.
Takao Eguchi 《Physics of the Earth and Planetary Interiors》1983,33(4):318-327
The overall pattern of the recent tectonic stress field in the eastern part of the Eurasian plate is inferred from the geological features of large transcurrent and reverse faults, graben structures and from focal mechanism solutions of shallow earthquakes. NE-SW striking trajectory lines, of maximum horizontal tectonic stress axis (σ Hmax), are estimated at the north of Tibet and mainland China, but its strike turns to easterly near the eastern margin of the Eurasian plate. This suggests that the main origin of the σ Hmax in East Eurasia is due to a compressive stress regime along, the Himalayan belt, Tibet and the Japan Trench (and also the Sakhalin and Nankai Trough). This tectonic stress field seems to provide some influence on the extensional tectonics in the Shansi region, Baikal, and also in the Okinawa Trough where the N-S opening has been confirmed. The systematic view of the tectonic stress field in East Eurasia, makes it possible to appreciate the fundamental background of a number of complicated intra-plate tectonics. 相似文献
9.
Mantle process beneath Philippine Sea back-arc spreading ridges: A synthesis of peridotite petrology and tectonics 总被引：2，自引：0，他引：2
Abstract In order to obtain a general view of the mantle process beneath a back‐arc basin spreading ridge, the diversity of peridotite petrology and tectonic occurrences in two back‐arc basin spreading ridges from the Philippine Sea were examined: the Parece Vela Rift and the Mariana Trough. The Parece Vela Basin spreading ridge (Parece Vela Rift) was a physically fast/intermediate‐spreading ridge, although many tectono‐magmatic features resemble those of slow‐ to ultraslow‐spreading ridges. Two unusual features of the Parece Vela Rift further demonstrate the uniqueness of the ridge: full‐axial development of oceanic core complexes and exposure of mantle peridotite at segment midpoints. The Parece Vela Rift yields a lithological assemblage of residual but still fertile lherzolite/harzburgite, plagioclase‐bearing harzburgite and dunite; similar assemblages are reported from the equatorial Mid‐Atlantic Ridge at the Romanche Fracture Zone and the ultraslow‐spreading ridges from the Indian and Arctic Oceans. The tectono‐magmatic characteristics of the Parece Vela Rift suggest that diffuse porous melt flow and pervasive melt–mantle interaction were the important mantle processes there. Globally, this ‘porous melt flow‐type’ mantle process is likely to occur beneath a segment midpoint of the ridge having a thick lithosphere, typically an ultraslow‐spreading ridge. In contrast, the Mariana Trough is a typical slow‐spreading ridge, exposing mantle peridotite at segment ends. The Mariana Trough yields a lithological assemblage of residual harzburgite and veined harzburgite, a common assemblage among the global abyssal peridotite suite. The tectono‐magmatic characteristics of the Mariana Trough suggest that channeled melt/fluid flow and limited melt–mantle interaction are the important mantle processes there, because of the colder wall‐rock peridotite in the segment end. This ‘channeled melt flow‐type’ mantle process is likely to occur in the shallow lithospheric mantle at the segment ends of any spreading ridges. 相似文献
10.
Recent crustal movements in eastern Taiwan were investigated based on geodetic and seismological data as a case study of the tectonics along a colliding plate boundary. Secular horizontal strain along the Longitudinal Valley, a probable arc-continent collision boundary between the Philippine Sea and Eurasion plates, is compressive with a large rate of 2 microstrains/year, and the maximum compression axis trends in NW-SE direction. This means that nearly two-thirds of the convergence rate between the two plates is consumed in the narrow zone along the valley and confirms the view that the valley is the plate boundary between the two. The amount of uplift in the Central Range, deduced from trigonometric leveling, reaches more than one meter during the past 60 years. Such active orogeny is caused by the high strain rate in this area. Horizontal displacement of the Coastal Range, a leading edge of the Philippine Sea plate, has a left-lateral component, suggesting that the boundary is a region of oblique collision and the range moves toward the north, producing subduction of the Philippine Sea plate off the Coast of northeastern Taiwan.An extensional strain pattern is found northeastern Taiwan near Hualien, in northern Taiwan near Ilan, and in southeastern Taiwan south Taitung. In northeastern Taiwan, the direction of the maximum extension axis is nearly parallel to the isodipth contours of deep-focus earthquakes that occurred under the southern part of the Ryukyu Trench. From a model calculation using a finite-element method, this pattern of strain is interpreted as an edge effect of the collision-subduction junction in northeastern Taiwan. The direction of the maximum extension in northern Taiwan forms high angles with the direction of the tectonic line near Ilan stretching from the Okinawa Trough. This fact is harmonious with the view that the Okinawa Trough is spreading. Extensional strain observed in southeastern Taiwan may be related to the eastward subduction since the area is situated on a transition zone, from collision to subduction. 相似文献
11.
张渤带陆地段现代构造应力场的非均匀特征 总被引：6，自引：1，他引：5
依据活动构造展布及震中分布等情况,将张渤带(张家口-渤海断裂带)陆地段及邻近地区划分为6个应力区,利用格点尝试法计算了1967～2006年间这6个分区内的529个震源机制解.结果显示,6个分区的应力结构较为一致,均为走滑型应力结构;但在应力方向上有明显不同,其应力主轴方向有由西北端的NEE向至东南端的近EW向呈顺时针旋转的趋势.此外,以1976年唐山地震与1998年张北地震为时间界限,计算了张渤带陆地段3个构造交汇段(即张北-怀来段、南口-三河段、天津-塘沽段,简称西段、中段、东段)上的地震震源机制解及各构造段在不同时段的平均主应力轴分布,得到了应力场随时间的变化特征.其中,西段与中段的构造应力场变化复杂,其应力主轴方向在唐山地震后经调整已基本回复至唐山地震前的状态;而东段的平均应力主轴呈顺时针旋转,目前仍为近EW向.张渤带陆地段现代构造应力场的时空非均匀变化特征可能与周边块体的相互作用及两次中强地震(唐山地震与张北地震)有关. 相似文献
12.
在总结、讨论冲绳海槽弧后张裂构造的地形地貌、地球物理场和动力背景特征的基础上,归纳出海槽北、中、南三段之间的差异,以及它们在陆坡、槽底、岛坡上的不同表现特征.槽底雁行排列的地堑及断层斜切入陆坡,伴随的断块隆眷作用往南加强,使得钓鱼岛一赤尾屿隆起带区别于其北边的陆架外缘隆起带,吕宋岛向台湾的碰撞挤压引起的旋张活动加强了海槽南段的地壳拉张,从北往南岛坡侧都可以追踪出双列岛孤特性.海槽内部构造现象不能为笼统的构造动力背景所能完全解释,需要对各个典型中央地堑的具体深入探测研究.鉴于地堑、地垒、断层以及它们所界定的构造单元和它们内部发生的岩浆作用各有特点,最后讨论了各个地段中央地堑的构造属性、动力要素的差异及变化规律,以期为海槽构造动力的进一步深入研究提供借鉴参考. 相似文献
13.
Roger Searle 《Earth and Planetary Science Letters》1980,51(2):415-434
The major tectonic elements of the Azores triple junction have been mapped using long-range side-scan sonar. The data enable the Mid-Atlantic Ridge axis to be located with a precision of a few kilometres. Major faults and other tectonic and volcanic elements of the ridge maintain their regional trend of 010° to 020° past the triple junction area. There is no oblique spreading, and only minor transform offsets of the Mid-Atlantic Ridge occur here. The main effect of the triple junction or Azores hot spot is to diminish the amplitude of the median valley to 200 m or less. There is no axial high: a topographic high seen on several profiles is located to the east of the Mid-Atlantic Ridge spreading axis and does not appear to have any fundamental significance.The third arm of the triple junction includes the Azores srreading centre which appears to have developed as a series of en echelon rifted basins (the Terceira Rift) extending from Formigas Trough at 36.8°N, 24.5°W to a point near 39.3°N, 28.8°W. There are indications that recent activity in the spreading centre may be concentrated in a series of ridges which flank the older rifted basins. Until recently the northwest end of the Terceira Rift was connected to the Mid-Atlantic Ridge axis either directly at an RRR junction, or via a transform fault. The triple junction has probably moved south during the last 6 Ma to a positin on the Mid-Atlantic Ridge near 38.7°N.Initiation of the Azores spreading centre may have occurred during the 36 Ma B.P. rearrangement of poles, with an RFF triple junction north from the East Azores fracture zone to the North Azores fracture zone and transferring a wedge of European plate to the African plate.The tectonic elements revealed by this study are in good agreement with inferred earthquake mechanisms and with the RM2 plate tectonic model of Minster and Jordan, but east-west motion between North America and Africa does not seem to be compatible with the other motions at the triple junction unless it is of very recent (2>3 Ma) origin. 相似文献
14.
受新生代太平洋板块弧后扩张剧烈活动的地缘特性影响,冲绳海槽构造特征复杂,南、中、北段在热液活动、断裂性质、火成岩特性、扩张时代等方面存在显著不同,因此认识该区各段构造活动性对查清其复杂地质特征具有重要意义.本文依据前人通过磁异常反演得到的居里面深度资料,利用热模拟的方法,对冲绳海槽各段深、浅构造活动性进行了探讨.模拟结果表明,南段软流层构造活动强度约为中、北段的6倍,而岩石圈浅层构造活动却相对较弱.该结论与前人所得到的地质地球物理资料相符,主要表现为:相对于中、北段,南段在海槽总体演化历程上裂陷较深;海底火成岩岩浆源区较深,结晶分异程度较弱,同化混染程度较强;切穿沉积基底的大型断裂较为发育,而沉积层内部的小型断裂分布相对稀疏;沉积层岩浆侵入活动较弱,海底所呈现出的热液活动区数量较少;现代地震活动较多,震源深度较大.根据模拟结果与实际资料的对比分析我们可以推测:(1)冲绳海槽北段可能还有一些热液区没有被探测到,也可能在历史演化进程中失去活力,或者被第四系沉积物覆盖;(2)南段存在孕育更多热液活动区的潜力. 相似文献
15.
综合地震层析成像与重磁数据的处理结果，选择26°N～36°N，120°E～130°E的范围作为研究区，讨论了黄、东海研究区的深部结构特点及其与周边各地质单元的相互关系，完成了研究区两条剖面的密度结构反演，认为东海陆架地区地壳厚度变化与大陆地区相比并不明显，显著减薄开始于冲绳海槽地区，中地壳消失；琉球岛弧处地壳厚度明显再度增加，特别是上地壳的厚度增加最大，推断其原因应与俯冲作用及俯冲带附近板块与地幔的运动速率之差有关.地球物理场“东西分带”是黄海—东海地区壳内结构从西向东变化的反映，但随着深度的增加，研究区的岩石层结构出现以近EW向为优势的构造格局.因此推断深部近EW向的异常是三叠纪时期南北板块碰撞、挤压所致，浅部的NE向条带异常是后期构造运动在岩石层较浅部位构造效应的反映.黄海—东海地区岩石层结构存在浅部与深部优势构造方向不协调的现象.层析成像结果证实了南黄海东缘断层的存在，还勾绘出绍兴—十万大山碰撞带为以40°左右的倾角向NW方向倾斜的高速带，另一条倾向基本相同的高速带则是南、北扬子块体结合带在深部的反映. 相似文献
16.
中国大陆位于欧亚板块的东南部, 受到印度板块、太平洋板块和菲律宾海板块的碰撞挤压与俯冲作用, 其构造应力场形态和动力学机制相当复杂. 本文采用伪三维有限元方法, 以世界应力图2008年版本数据(WSM2008)的应力方向和应力型两类指标作为主要约束, 对中国大陆及邻区的动力驱动机制进行数值模拟, 给出了中国大陆周边地区板块边界力的大小和方向估计. 同时对3个典型情况的数值模型进行了分析. 结果显示, 软流层静压推力对该区域构造应力场影响相对较小, 板块边界力作用则起主导作用; 印度板块在喜马拉雅造山带对欧亚板块的碰撞控制了中国大陆地区应力场的基本形态, 是形成川滇地区走滑型地震为主的重要原因; 琉球海沟——南海海槽俯冲带边界力显示了挤压-张性的分段特性, 贝加尔裂谷表现为拉张作用. 进一步的分析表明, 中国大陆大部分区域内最大水平剪应力分布图像与该地区地震辐射能量密度的分布存在较好的空间正相关性． 相似文献
17.
针对2015年4月25日发生于印度板块北边界中段的尼泊尔8.1级地震后,青藏高原中强以上地震活动呈现NE向条带分布的现象,本文将区域地质构造动力环境和以GPS水平位移为约束的数值模拟相结合,初步分析研究了这一地震活动条带的基本特征和形成机理;进而将其与1996年前后出现在青藏高原及东北部邻区的"西藏榭通门-内蒙古包头"NE向地震活动条带、以及该条带形成后强震活动由东向西的迁移状况进行比较,探讨了目前的NE向地震活动条带对未来强震活动趋势的预示意义。结果认为:尼泊尔8.1级地震后青藏高原NE向中强以上地震活动条带,是在印度板块北推挤压动力持续作用下,因青藏高原NE向构造应力加强引起的构造活动响应,并与尼泊尔大地震低角度逆冲错动和地壳介质能量传递影响有关;而未来地震趋势可能使该条带附近强震活动"填空",进而使该条带东、西两侧较大范围强震活动性增强。 相似文献
18.
《Earth and Planetary Science Letters》2006,241(3-4):372-380
Oceanic plateaus are mafic igneous provinces commonly thought to derive from ascending mantle plumes. By far the largest, the Ontong Java Plateau (OJP) was emplaced ca. 120 Ma, with a much smaller magmatic pulse of ca. 90 Ma. Of similar age and composition, the Manihiki and Hikurangi Plateaus (MP and HP) are separated from the OJP by ocean basins formed during the Cretaceous long normal magnetic period. I present new seafloor fabric data that indicate the three plateaus formed as one (OJMHP). The data support previous interpretations that the Osbourn Trough is the relict of the spreading center that separated the MP and HP but they require a different interpretation than prevailing tectonic models for the Ellice Basin. Closely spaced, large offset, fracture zones in the Ellice Basin bound former right-stepping spreading segments that separated the OJP and MP. The MP was emplaced near the axis of the Pacific–Phoenix ridge and additional plateau fragments formerly bordered its eastern margins. Following OJMHP break-up, seafloor spreading removed these fragments to the east and SSE, together with the symmetric conjugates to the extant Phoenix magnetic lineations. 相似文献
19.
Lying to the southeast of the East China Sea continental shelf, the Okinawa Trough is believed to have been formed by crustal spreading behind the Ryukyu island arc. It has the highest mean heat flow among the Pacific marginal basins. The mean of 18 reliable measurements is3.34±2.75HFU. The next highest mean heat flow for a marginal basin is2.53±1.60HFU for the Fiji Plateau. The high mean value for the Okinawa Trough may be partially attributable to a sampling bias because most measurements were made in or near the well-sedimented central “rift” or graben. The reported values range from 0.36 to 10.49 HFU, with low values probably resulting from hydrothermal circulation in an area of large relief. The high heat flow suggests that the age of the Okinawa Trough may be as young as 2 Ma. Such an estimate is in gross agreement with the inferred Plio-Pleistocene age for the drifting in the Okinawa Trough. The opening of the Okinawa Trough may continue onto Taiwan but the relation between the opening of the trough and the occurrence of a nearby, onshore geothermal resource area remains unsolved. 相似文献
20.
Yngve Kristoffersen 《Earth and Planetary Science Letters》1978,38(2):273-290
We have examined available magnetic and gravity data bearing on the initiation of sea-floor spreading in the North Atlantic between Ireland and Newfoundland. The change in character of the magnetic field on the continental margin on either side of the Atlantic from a landward magnetic quiet zone to a seaward “noisy”, magnetic signature is postulated to be related to a change from continental to oceanic crust. Sea-floor spreading between Ireland and Newfoundland was initiated during the long normal geomagnetic polarity interval in the Late Cretaceous. Rockall Trough may have opened at this time. At the end of the normal polarity interval (Late Santonian) the ridge axis jumped westward to bypass Rockall Trough and the related offset initiated the Charlie Gibbs fracture zone.A reconstruction is presented for the relative position between North America and Europe prior to the initiation of sea-floor spreading in the Late Cretaceous. 相似文献