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1.
南海深地震探测的重要科学进程:回顾和展望   总被引：3，自引：0，他引：3  
南海是西太平洋最大的边缘海之一,研究其深部地壳的结构对深入认识南海共轭边缘的构造属性、深海盆形成演化历史、含油气盆地的形成机制均具有十分重要的科学意义。南海地壳结构的深地震探测从构造区域上可分为南海北部陆缘、南海南部陆缘、南海中部深海盆等几个海域,在探测技术上经历了声纳浮标、双船扩展剖面(expanding spread profile,ESP)、海底地震仪(ocean bottom seismometer,OBS)探测3个阶段。特别是近20年OBS探测蓬勃发展,从南海北部、发展到南海南部、再到南海中部,从二维直线探测到三维网格探测。这些探测和研究得到了宝贵的深部地壳结构信息,为南海的形成演化理论提供了重要依据,同时也推动了国产OBS的应用和人才队伍的培养。而最新完成的深海盆三维OBS探测标志了一个新的历史阶段,具有非常深远的科学意义。  相似文献   

2.
在马尼拉海沟俯冲带前缘开展了二维海底地震仪(OBS)探测实验,布置了一条东西走向的深地震测线——OBS2015-2。以该测线上的2个台站(OBS04和OBS08)为例,阐述了此次实验所用短周期国产OBS的数据处理流程。包括从原始数据到SAC格式、再到SEGY格式的转换;同时包括炮点位置校正和OBS位置校正。数据处理结果表明,OBS2015-2测线的数据质量良好,综合地震剖面显示来自深部的震相(如Ps P、Pg、Pm P等)信息十分清晰。利用Rayinvr软件正演试算,进一步确认了震相类型,特别是来自于输入板块莫霍面的反射震相非常丰富,为马尼拉俯冲带的输入板块地壳底界面的确定提供了重要的数据基础。  相似文献   

3.
南海西南次海盆广角地震探测   总被引：2，自引：0，他引：2  
2010年12月—2011年3月在南海西南次海盆开展了海底地震仪(Ocean Bottom Seismometer,OBS)探测,采用Sedis IV型、I-4C型和MicrOBS3种不同型号的OBS,以4×24.5L的大容量气枪为震源,获得了覆盖西南次海盆残留扩张脊的3D人工地震数据。从处理的地震数据可知,此次试验是一次比较成功的地震实验,OBS地震记录清晰、震相丰富,所使用的气枪有足够的能量输出,显示了其良好的工作能力。选取剖面1中的7台OBS进行了2D剖面处理。初步建模结果表明,南海西南次海盆地壳结构为普通洋壳,海山顶部沉积层很薄,莫霍面埋深较浅。  相似文献   

4.
南海北部陆缘洋陆转换带实施的OBS2018-H2测线的地壳速度结构, 将为探讨南海张裂-破裂机制提供重要证据。文章介绍了OBS2018-H2测线前期数据处理流程, 包括多道反射地震数据处理、海底地震仪OBS (Ocean Bottom Seismometer)数据格式转换、炮点和OBS位置校正, 以及OBS震相的初步识别, 并对地壳结构进行了初步分析。结果表明: 炮点和OBS位置校正效果良好; 多道反射地震数据为建立初始速度模型提供了良好约束; OBS综合地震剖面识别了多组清晰的P波震相, 包括Pw、Pg、PmP和Pn震相。根据测线西侧OBS36、OBS37两台站的震相分布特征初步估算台站下方地壳厚度约为6~7km, 与根据多道地震剖面LW3的双程走时估算的厚度6~9km大致相符。  相似文献   

5.
通过挖掘海底地震仪记录的转换横波信息,可以促进对地壳岩性、均质性的认识。以南海南沙地块OBS973-1剖面上18个台站的数据为实例,阐明了海底地震仪横波震相识别的方法。首先对三分量OBS(Ocean Bottom Seismometer)地震数据进行带通滤波、维纳滤波、极化滤波等去噪处理,然后利用能量扫描法求得极化角进行水平分量坐标旋转,求取最佳径向分量。数据处理结果表明,相对于OBS记录的磁罗盘方位角,能量扫描法求取的极化角更为准确可靠。最后通过OBS973-1地震剖面垂直分量与径向分量上的纵横波走时对比、质点运动轨迹、速度模型试算等手段,进一步确定了转换横波震相的类别。在南沙地块OBS探测中成功地在10个台站中识别出了PgSs、PnSc、Pms等震相,不仅可以为下一步横波速度结构模拟提供坚实的数据基础,而且可以为今后OBS转换横波在其他地区的有效应用与推广提供借鉴。  相似文献   

6.
南黄海OBS 2013海陆联合深地震探测初步成果   总被引：4，自引：0，他引：4       下载免费PDF全文
为了研究渤海—山东半岛—南黄海一线的深部构造特征,利用海区气枪震源和陆区爆破震源探测,于2013年在胶东、渤海和南黄海布设了一条海陆联合深部地震探测剖面。海陆联测剖面包括渤海和南黄海两条海底地震仪(Ocean Bottom Seismometer,OBS)测线和一条陆上地震测线,是首次在南黄海地区布设的OBS深地震测线。文章对南黄海段测线上的海底地震仪数据进行了数据预处理,其中包括地震数据解编处理、截裁处理等,结果表明,此次实验海底地震仪记录质量良好,可以清晰地识别出Ps、Pg、Pm P等多组震相,还首次观察到了来自千里岩隆起带上的P波震相,说明数据处理流程是可行的;再结合地质地球物理资料,初步分析了南黄海不同构造单元的震相特征,为下一步地壳速度结构的模拟及解释工作奠定了良好的基础。  相似文献   

7.
综述了马里亚纳海沟俯冲带二维(2D)和三维(3D)深地震探测的研究进展,要点如下:1)伊豆—小笠原岛弧下方玄武质火山岩的物质成分基本一致,中地壳的速度特征与陆壳相似,岛弧底部镁铁质到超镁铁质的壳幔过渡层(crustmantle transition layer,CMTL)通过拆沉(delamination)等作用返回地幔,实现由岛弧到陆壳的演化;2)不同年龄的洋内岛弧具有不同的速度结构特征,说明它们的地壳密度不同,可用不同的模型来解释;3)岛弧体系中速度结构及演化历史在时间和空间上的特征变化,揭示了俯冲开始时洋壳和地幔的属性以及俯冲开始的原因。马尼拉海沟与马里亚纳海沟相比,虽然地质背景不同,但研究方法可以借鉴。今后的马尼拉海沟俯冲带探测的重点包括海底地震仪2D/3D联合探测、海底电磁探测,以及天然地震的长期观测等。马尼拉海沟项目的实施将加深对俯冲带运行机制的认识。  相似文献   

8.
马尼拉海沟几何形态特征的构造演化意义   总被引：4，自引：0，他引：4  
通过对马尼拉海沟海底地形地貌、构造特征及其相关地震等数据资料的分析,结合俯冲带动力学数值模拟成果,尤其是Schellart等的模式,详细讨论了马尼拉海沟几何形态、海沟南北段俯冲角度突变等构造特征。分析认为,南海中代表古扩张脊的黄岩海山链的俯冲挤入对马尼拉俯冲带的几何形态没有造成较大的影响,其几何形态较符合中等长度(2000～3000km)的海沟模型。由海沟后退和板片反转引起的平行于马尼拉海沟方向的地幔流加剧了海沟南北段俯冲角度的突变。  相似文献   

9.
由于南海是西太平洋区域众多边缘海的主要组成部分，故了解南海从同裂谷到海底扩张的发展史对阐明西太平洋的构造演化是非常重要的。本文阐述了通过综合利用新获得的和已有的地球物理资料研究南海北部大陆边缘从裂谷到扩张过程的变迁。南海的最北部地区是中日合作项目(JCCP)一部分，该项目分1993年和1994年两个阶段。JCCP调查的目的是揭示大陆壳和深海盆间的过渡地区的地震与磁力特征。南海磁力和海洋重力资料表明了其张裂陆壳和汇聚边缘过去与现在的构造特征。全磁和三维磁力资料清楚表明海盆的线型磁异常特征和变化的海盆边缘磁异常特征。南海重、磁及地震资料和其他地球物理、地质的分析可以得出如下结论： (1)N-s向海底扩张始于早始新世。它至少有四个独立的演化阶段，其扩张的方向和速率是不稳定的．扩张从32Ma一直持续到17Ma； (2)陆洋边界(COB)的东西两边在现代构造形式上的明显差异暗示东部陆壳的破裂受走滑断裂的控制； (3)下地壳的地震高速层似乎被俯冲到伸展的陆壳下； (4)最上层的沉积和覆在第三纪火山上的下地壳的上部以大陆边缘区的磁力异常体为基底； (5)位于大陆边缘的磁力平静带(MQZ)对应COB； (6)无磁或弱磁层可能导致MQZ，地磁退磁的一个原因是当高温地幔物质被俯冲时地热的变化．另一种解释是每个往返磁极玄武岩的横向连续消失在上部合成磁场。 我们正建立一个包含地震数据、潜在油田、地壳和地热结构与其它地球物理数据的人工数据库系统。以便更好地对过去、现在和将来环日本的深海环境的变化进行研究，即海沟、海槽、俯冲带、边缘盆地和岛弧。该数据库的一些特征是对来源不同的全球数据的多方面研究和有目的定向搜集资料。  相似文献   

10.
海底地震仪(ocean bottom seismometer,OBS)探测是获得海底深部地壳结构的首选方法。正确拾取OBS记录中折射/反射震相,对获得准确的深部速度结构非常重要。当OBS布设在崎岖海底时,起伏的海底地形会影响OBS地震记录剖面中Pg、Pm P、Pn等岩石圈内部震相的展布特征,如南海东部次海盆中横穿珍贝-黄岩海山链的A4M4地震测线和西南印度洋中脊横穿扩张脊的Y3Y4测线,强烈的地形高差变化增加了这些测线上OBS台站地震剖面的震相识别难度。在震相拾取之前,通过地形校正方法消除海底地形对震相的影响;地形校正后,根据震相视速度及其展布趋势可以准确地识别震相,有效地提高了震相识别的可靠性。地形校正方法在上述地区的震相识别与速度结构研究方面发挥了重要作用,同时为今后在其他地形变化复杂地区的OBS震相识别提供了经验与借鉴。  相似文献   

11.
Understanding the development from syn-rift to spreading in the South China Sea (SCS) is important in elucidating the western Pacific's tectonic evolution because the SCS is a major tectonic constituent of the many marginal seas in the region. This paper describes research examining the transition from rifting to spreading along the northern margin of the SCS, made possible by the amalgamation of newly acquired and existing geophysical data. The northernmost SCS was surveyed as part of a joint Japan-China cooperative project (JCCP) in two phases in 1993 and 1994. The purpose of the investigation was to reveal seismic and magnetic characteristics of the transitional zone between continental crust and the abyssal basin. Compilation of marine gravity and geomagnetic data of the South China Sea clarify structural characteristics of its rifted continental and convergent margins, both past and present. Total and three component magnetic data clearly indicate the magnetic lineations of the oceanic basin and the magnetic characteristics of its varied margins. The analyses of magnetic, gravity and seismic data and other geophysical and geological information from the SCS led up to the following results: (1) N-S direction seafloor spreading started from early Eocene. There were at least four separate evolutional stages. Directions and rates of the spreading are fluctuating and unstable and spreading continued from 32 to 17 Ma. (2) The apparent difference in the present tectonism of the eastern and western parts of Continent Ocean Boundary (COB) implies that in the east of the continental breakup is governed by a strike slip faulting. (3) The seismic high velocity layer in the lower crust seems to be underplated beneath the stretched continental crust. (4) Magnetic anomaly of the continental margin area seems to be rooted in the uppermost sediment and upper part of lower crust based on the tertiary volcanism. (5) Magnetic quiet zone (MQZ) anomaly in the continental margin area coincides with COB. (6) The non-magnetic or very weakly magnetized layer is probably responsible for MQZ. One of the causes of demagnetization of the layer is due to hydrothermal alteration while high temperature mantle materials being underplated. Another explanation is that horizontal sequences of basalt each with flip-flop magnetization polarity cancel out to the resultant magnetic field on the surface. We are currently developing a synthetic database system containing datasets of seismicity, potential field data, crustal and thermal structures, and other geophysical data to facilitate the study of past, contemporary and future changes in the deep sea environment around Japan; i.e. trench, trough, subduction zones, marginal basins and island arcs. Several special characteristics are an object-oriented approach to the collection and multi-faceted studies of global data from a variety of sources.  相似文献   

12.
The continental breakup which gave way to the formation of the oceanic South China Sea (SCS) basin began in the latest Cretaceous in the northeastern SCS and propagated in southern and western direction over a long period of time, possibly more than 40 m.y. The seafloor spreading history of the South China Sea has been interpreted in different ways in the past and the debate over the correct timing of the major tectonic events continues. We review the different models that have been published and present a revised interpretation of seafloor spreading anomalies based on three datasets with documented high quality which cover all of the SCS but the northernmost and southernmost parts. We can precisely date the onset of seafloor spreading in the central part of the SCS at 32 Ma. After a ridge jump at 25 Ma spreading also began in the southwestern sub-basin and spreading ended at 20.5 Ma in the entire basin, followed by a phase of magmatic seamount formation mainly along the abandoned spreading ridge. Spreading rates vary from 56 mm/yr in the early stages to 72 mm/yr after the ridge jump to 80 mm/yr in the southwestern sub-basin. We find indications for a stepwise propagation of the seafloor spreading from northeast to southwest in segments bounded by major fracture zones. Seafloor spreading ended abruptly probably because the subduction zone along the eastern and southern boundary of the SCS (of which today the Manila Trench remains) was blocked by collision with a continental fragment, possibly the northern part of Palawan or a part of the Dangerous Grounds.  相似文献   

13.
The seafloor spreading of the South China Sea (SCS) was previously believed to take place between ca. 32 and 15 Ma (magnetic anomaly C11 to C5c). New magnetic data acquired in the northernmost SCS however suggests the existence of E–W trending magnetic polarity reversal patterns. Magnetic modeling demonstrates that the oldest SCS oceanic crust could be Late Eocene (as old as 37 Ma, magnetic anomaly C17), with a half-spreading rate of 44 mm/yr. The new identified continent–ocean boundary (COB) in the northern SCS generally follows the base of the continental slope. The COB is also marked by the presence of a relatively low magnetization zone, corresponding to the thinned portion of the continental crust. We suggest that the northern extension of the SCS oceanic crust is terminated by an inactive NW–SE trending trench-trench transform fault, called the Luzon–Ryukyu Transform Plate Boundary (LRTPB). The LRTPB is suggested to be a left-lateral transform fault connecting the former southeast-dipping Manila Trench in the south and the northwest-dipping Ryukyu Trench in the north. The existence of the LRTPB is demonstrated by the different patterns of the magnetic anomalies as well as the different seafloor morphology and basement relief on both sides of the LRTPB. Particularly, the northwestern portion of the LRTPB is marked by a steep northeast-dipping escarpment, along which the Formosa Canyon has developed. The LRTPB probably became inactive at ca. 20 Ma while the former Manila Trench prolonged northeastwards and connected to the former Ryukyu Trench by another transform fault. This reorganization of the plate boundaries might cause the southwestern portion of the former Ryukyu Trench to become extinct and a piece of the Philippine Sea Plate was therefore trapped amongst the LRTPB, the Manila Trench and the continental margin.  相似文献   

14.
南海大洋钻探及海洋地质与地球物理前沿研究新突破   总被引：2，自引：2，他引：0  
南海是西太平洋地区规模最大且具有代表性的边缘海盆地之一。经过近几十年的研究积累，尤其是通过实施5个国际大洋钻探航次(1999–2018年)与国家自然科学基金委“南海深海过程演变”重大研究计划(2011–2019年)，我国科学家获得了大量宝贵的第一手资料，取得了一系列创新进展与重大突破，标志着南海海洋地质与地球物理研究正走向国际前沿。重要研究成果包括:(1)新提出南海是“板缘张裂”盆地，与经典的大西洋型陆缘模式不同；(2)大洋钻探首次获取了基底玄武岩样品，结合中国在南海首次深拖地磁测量实验，精确测定了南海海盆玄武岩年龄，揭示南海海盆从东向西分段扩张；(3)大洋钻探结果发现南海陆缘岩石圈减薄之初岩浆迅速出现，未发现缓慢破裂造成的蛇纹岩出露；(4)发现南海扩张结束后仍存在大量岩浆活动，可能受控于多种构造与地幔因素；(5)地球化学证据与地球动力学模拟都显示南海岩浆的形成受到周边俯冲带的影响。目前我国的海洋地球科学正在进入崭新的发展阶段，有望以南海为基点，开始拓展到周边大洋，通过主导大型研究计划以及建设我国大洋钻探平台，以提升我国在南海、西太平洋与印度洋海洋地质科学研究的实质性影响力与引领地位。  相似文献   

15.
Igneous rocks in the northern margin of the South China Sea (SCS) have been identified via high resolution multi-channel seismic data in addition to other geophysical and drilling well data. This study identified intrusive and extrusive structures including seamounts and buried volcanoes, and their seismic characteristics. Intrusive features consist of piercement and implicit-piercement type structures, indicating different energy input associated with diapir formation. Extrusive structures are divided into flat-topped and conical-topped seamounts. Three main criteria (the overlying strata, the contact relationship and sills) were used to distinguish between intrusive rocks and buried volcanos. Three criteria are also used to estimate the timing of igneous rock formation: the contact relationship, the overlying sedimentary thickness and seismic reflection characteristics. These criteria are applied to recognize and distinguish between three periods of Cenozoic magmatism in the northern margin of the SCS: before seafloor spreading (Paleocene and Eocene), during seafloor spreading (Early Oligocene–Mid Miocene) and after cessation of seafloor spreading (Mid Miocene–Recent). Among them, greater attention is given to the extensive magmatism since 5.5 Ma, which is present throughout nearly all of the study area, making it a significant event in the SCS. Almost all of the Cenozoic igneous rocks were located below the 1500 m bathymetric contour. In contrast with the wide distribution of igneous rocks in the volcanic rifted margin, igneous rocks in the syn-rift stage of the northern margin of the SCS are extremely sporadic, and they could only be found in the southern Pearl River Mouth basin and NW sub-sea basin. The ocean–continent transition of the northern SCS exhibits high-angle listric faults, concentrated on the seaward side of the magmatic zone, and a sharply decreased crust, with little influence from a mantle plume. These observations provide further evidence to suggest that the northern margin of the SCS is a magma-poor rifted margin.  相似文献   

16.
我国南海历史性水域线的地质特征   总被引：3，自引：1，他引：2  
40a的海洋地质、地球物理实测研究表明,九段线不仅是显示我国南海主权的历史性水域线,而且总体上也是南海与东部、南部和西部陆区及岛区的巨型地质边界线。根据实测数据,本文将从地质成因、来源、演化的角度论述此南海历史性水域线的合理性。主要结论包括:历史性水域线的东段在地形上基本与马尼拉海沟一致,海沟西侧为南海中央海盆洋壳区,东侧为菲律宾群岛。根据国际地质研究的资料,菲律宾群岛始新世以前位于较偏南的纬度,后来于中晚中新世(距今16~10Ma)仰冲于南海中央海盆之上,因此菲律宾群岛是一个外来群岛。而黄岩岛在马尼拉海沟以西,是中央海盆洋壳区的一个岛礁,与菲律宾群岛成因不同。南海历史性水域线的南段在地形上基本与南沙海槽一致,伴随南沙地块由北部陆缘向南裂离,古南海洋壳沿此海槽以南俯冲至加里曼丹岛陆壳之下,因此南沙地块与加里曼丹陆块为两个来历不同的地块。南海历史性水域线西段的分布在地形上与越东巨型走滑断裂带基本一致,可能与西沙地块、中沙地块、南沙地块从南海北部陆缘向南滑移有关。南沙地块北缘陡直的正断层结构,突显中央海盆是拉裂形成,其基底和中新生代地层与北部珠江口盆地的地层结构可以对比,说明南沙岛礁原属我国华南大陆南缘,后因南海的形成裂离至现今的位置。  相似文献   

17.
Compared to the northern South China Sea continental margin, the deep structures and tectonic evolution of the Palawan and Sulu Sea and ambient regions are not well understood so far. However, this part of the southern continental margin and adjacent areas embed critical information on the opening of the South China Sea (SCS). In this paper, we carry out geophysical investigations using regional magnetic, gravity and reflection seismic data. Analytical signal amplitudes (ASA) of magnetic anomalies are calculated to depict the boundaries of different tectonic units. Curie-point depths are estimated from magnetic anomalies using a windowed wavenumber-domain algorithm. Application of the Parker–Oldenburg algorithm to Bouguer gravity anomalies yields a 3D Moho topography. The Palawan Continental Block (PCB) is defined by quiet magnetic anomalies, low ASA, moderate depths to the top and bottom of the magnetic layer, and its northern boundary is further constrained by reflection seismic data and Moho interpretation. The PCB is found to be a favorable area for hydrocarbon exploration. However, the continent–ocean transition zone between the PCB and the SCS is characterized by hyper-extended continental crust intruded with magmatic bodies. The NW Sulu Sea is interpreted as a relict oceanic slice and the geometry and position of extinct trench of the Proto South China Sea (PSCS) is further constrained. With additional age constraints from inverted Moho and Curie-point depths, we confirm that the spreading of the SE Sulu Sea started in the Early Oligocene/Late Eocene due to the subduction of the PSCS, and terminated in the Middle Miocene by the obduction of the NW Sulu Sea onto the PCB.  相似文献   

18.
About 16,000 km of multichannel seismic (MCS), gravity and magnetic data and 28 sonobuoys were acquired in the Riiser-Larsen Sea Basin and across the Gunnerus and Astrid Ridges, to study their crustal structure. The study area has contrasting basement morphologies and crustal thicknesses. The crust ranges in thickness from about 35 km under the Riiser-Larsen Sea shelf, 26–28 km under the Gunnerus Ridge, 12–17 km under the Astrid Ridge, and 9.5–10 km under the deep-water basin. A 50-km-wide block with increased density and magnetization is modeled from potential field data in the upper crust of the inshore zone and is interpreted as associated with emplacement of mafic intrusions into the continental margin of the southern Riiser-Larsen Sea. In addition to previously mapped seafloor spreading magnetic anomalies in the western Riiser-Larsen Sea, a linear succession from M2 to M16 is identified in the eastern Riiser-Larsen Sea. In the southwestern Riiser-Larsen Sea, a symmetric succession from M24B to 24n with the central anomaly M23 is recognized. This succession is obliquely truncated by younger lineation M22–M22n. It is proposed that seafloor spreading stopped at about M23 time and reoriented to the M22 opening direction. The seismic stratigraphy model of the Riiser-Larsen Sea includes five reflecting horizons that bound six seismic units. Ages of seismic units are determined from onlap geometry to magnetically dated oceanic basement and from tracing horizons to other parts of the southern Indian Ocean. The seaward edge of stretched and attenuated continental crust in the southern Riiser-Larsen Sea and the landward edge of unequivocal oceanic crust are mapped based on structural and geophysical characteristics. In the eastern Riiser-Larsen Sea the boundary between oceanic and stretched continental crust is better defined and is interpreted as a strike-slip fault lying along a sheared margin.  相似文献   

19.
The Nereus Deep (23°N) lies in the central portion of the Red Sea, in a region which marks a transition between the nearly continuous axial rift valley of the southern Red Sea and the northern Red Sea, where a well defined axial rift is absent. The deep-tow survey and associated heat flow measurements reported here show that the Nereus Deep is a short segment of axial rift, and it is the northernmost deep where petrology, heat flow, magnetics, and morphology all indicate classic seafloor spreading. Heat flow measured in the Nereus Deep is characterized by non-linear gradients and closely-spaced variability indicative of active hydrothermal circulation associated with seafloor spreading. The two axial highs which we have mapped in Nereus differ markedly in that the southernmost appears younger or at least has had a more recent phase of volcanism. The two axial highs are offset left laterally approximately 2 km. This small offset or bend in the axial course has been labelled the Nereus shear zone, and, despite its small extent, it mimics many of the major features of small offset, slow-slipping transform faults. This shear zone may result from shear stresses associated with misalignments in succeeding volcanic episodes. The Nereus Deep appears to represent one of the earliest phases of seafloor spreading. The Red Sea seems to be opening towards the north, and the Nereus Deep is near the tip of propagation, but it is clear from this study that rift propagation in a site of initial rifting differs greatly from that observed along a well developed, fast spreading center like the East Pacific Rise.  相似文献   

20.
经过对"探宝号"调查船在2001年8月在南海东北部陆坡及台湾南部恒春海脊海域采集的多道地震剖面资料进行的地震反射波数据分析、研究和解释,结果表明:(1)南海东北部陆坡段区域和台湾南部恒春海脊海域地震剖面上均显示有被作为天然气水合物存在标志的BSR,但两区域构造成因、形式和相关地质环境的不同造成了此两处的天然气水合物成因及过程的不同.(2)南海东北部陆坡区域的水合物形成与该区广泛发育的断裂带、滑塌构造体及其所形成的压力场屏蔽环境有关,而台湾南部恒春海脊海域的天然气水合物的形成则与马尼拉海沟俯冲带相关的逆冲推覆构造、增生楔等及其所对应的海底流体疏导体系有关.(3)南海陆缘区域广泛发育有各种断裂带、滑塌构造体、泥底辟、俯冲带、增生楔等,且温压环境合适,是天然气水合物矿藏极有可能广泛分布的区域.  相似文献   

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