南海北部陆坡东西段新构造的异同及对BSR分布的影响
发布时间：2018-10-18 18:24
【摘要】：南海作为西太平洋最大的边缘海，发育了众多的新生代盆地，蕴含了丰富的能源资源。本文通过地震剖面、震源机制解手段对南海北部的新构造特征进行了系统、综合性研究。这对于理解南海北部的新构造的动力学机制、天然气水合物的成藏以及海底地质灾害的防治具有重要意义。通过研究得出几点结论： （1）南海北部新生代岩浆岩分布从东向西可划分为三个岩浆活动集中区：琼东南-西沙区、神狐区和东沙区。各区域岩浆岩的产出位置的控制因素有所差异，其中琼东南-西沙区的岩浆岩平面展布受右行右阶的走滑断裂控制；神狐区岩浆岩位于NW向与NE向断裂的交汇处，侵位空间受先存断裂制约；东沙区岩浆岩的产生与东沙运动期间区域伸展过程有直接关系。 （2）根据地震的分布特征，并结合震源机制解的情况，将南海陆缘地震带也分为三个区域。东部受到菲律宾海板块沿吕宋岛弧的NW向强烈挤压，强震多次发生，地震活动性最强；西部受红河断裂的走滑影响，地震活动性较高，但依然有强震记录；而位于东部的碰撞型和西部的转换型板块边界中间位置的珠江口区域，地震活动性很微弱，非但没有大震、强震发生，而且中、小地震也较为不发育。同时通过对震源机制解的研究表明，南海北部发震断裂也有所不同。东部的发震断裂多以NE向右行走滑为主，中部地震活动则受正断层的控制，西部发震断裂多为NW向的右行走滑断裂。 （3）利用Coulomb模拟对南海北部东段、中段以及西段的历史地震进行应力场模拟，认为南海西部1936年广西灵山地震触发了1988年发生在北部湾的地震，1605年琼山地震的余震发生在应力等值线发育较为宽缓的区域。1988年北部湾发生的4.8级地震，导致了1995年之后该区域的地震发育。1994年、1995年发生的6级地震，以应力降低为主，，余震主要发育在发震断裂上。南海北部中段1962年河源地震的余震主要发育在断裂的NW端，1969年阳江地震余震集中在断裂的北侧。另外，这两次地震的余震多分布于应力增强较小的区域或者应力增加区与应力降低区的分界线处，应力增大的极大值区几乎没有余震分布。南海东部1878年的6级地震其NE向的应力增长区也覆盖了1906年的地震，从时间上来看，其触发1906年地震的可能性较大。另外，1878年地震SW向的应力增长呈弧形与1918年7.5级地震震中相交，其极有可能是1918年地震的触发因素。1992年东沙群岛地震应力增加区走向为NE向，降低区走向为NW向，余震多分布于发震断裂西侧应力增长区。另外，东沙群岛地震应力增长区覆盖1994年台湾浅滩的震源位置，前者可能为触发后者的主要因素。 （4）南海北部陆缘东部受东沙运动影响，高压地层发生了卸压，底辟构造不发育，这就使得东部天然气水合物气源的运输系统为断层-断层的相结合的方式。而西部受东沙运动的影响较小，底辟构造十分发育，使得西部以断层-底辟的组合样式作为天然气水合物气源运移的主要通道。 （5）南海北部陆缘新构造演化受太平洋构造域以及新特提斯构造域的联合制约。南海北部陆缘断裂的发育特征因分布位置的不同而存在差异，可分为东、西两部分。东部断裂活动以继承性为主，而西部发育大量新生性断层，局部发生构造反转。在时间尺度上，不同构造域对南海北部的影响范围也存在差异。从晚白垩世到晚渐新世（32Ma），整个南海北部受太平洋构造域的影响，几乎不受特提斯洋构造域的影响。通过断裂活动性研究表明，中新世珠江口盆地受特提斯构造域控制。伴随着晚中新世末期发生的东沙运动，珠江口盆地东部开始受太平洋构造域的影响。之后，太平洋板块的汇聚速率的增大，其对珠江口盆地的影响范围逐渐向西扩大。挽近时期，现今两大构造域的边界大致在112°E。
[Abstract]:As the largest marginal sea in the western Pacific Ocean, the South China Sea developed numerous Cenozoic basins, which contained abundant energy resources. In this paper, the new tectonic feature of the northern South China Sea is systematically and comprehensively studied by means of seismic section and focal mechanism solution. This is of great significance for understanding the dynamics mechanism of the new structure in the northern South China Sea, the formation of natural gas hydrate and the prevention and treatment of submarine geological disasters. Through the study, several conclusions are drawn: (1) The distribution of Cenozoic magmatic rocks in the northern South China Sea can be divided into three magmatic activity concentrations from east to west: southeast of Qiong-Xisha area, Fox area and east. The control factors of the output position of the magmatic rocks in each region are different, among which, the plane distribution of the magmatic rocks in the southeast-Xisha area of Qiong is controlled by the left-right-order slip-slip fault, and the rock-magmatic rocks in the Fox area are located at the junction of NW and NE trending faults, and the invaded space is subjected to pre-storage fracture. Constraints; the formation of magmatic rocks in the east sand area is directly related to the regional extension process during the east-sand movement. (2) According to the distribution characteristics of the earthquake, and combining with the solution of the focal mechanism, the continental margin of the South China Sea is also divided. There are three regions in the east. The eastern part of the Philippine Sea plate is strongly extruded along the NW direction of the Luzon island arc, the strong earthquakes have occurred many times, the seismic activity is strongest, the west is influenced by the strike-slip of the red river fault, and the seismic activity is high, but still There is a strong earthquake record; whereas in the eastern collision type and the middle position of the transition plate boundary in the west, the area of the Pearl River mouth, the seismic activity is very weak, far from the large earthquake, the strong earthquake occurs, and the small earthquake also The research on the solution of the focal mechanism shows that the earthquake in the north of the South China Sea is broken. The earthquake activity in the east is dominated by NE trending right, and the seismic activity in the middle part is controlled by normal fault, and the fault of the western seismogenic fault is NW trending right. The history of the east section, the middle section of the South China Sea and the east section of the South China Sea is simulated by Coulomb simulation. The stress field is simulated in the west of the South China Sea in 1936, which triggered the earthquake in the Beibu Gulf in 1988, and the aftershocks of the Qionshan earthquake in 1995 occurred in the region where the stress isolines developed slowly. Seismic development of the region after 1995, which resulted in the earthquake development of the region since 1995. In 1994, the magnitude 6 earthquake occurred in 1995 with stress reduction as the main aftershock. The aftershocks of the river source earthquake in the middle section of the South China Sea in 1962 are mainly developed at the NW end of the fault, and the aftershocks of the Yangjiang earthquake in 1969 On the north side of the fracture, the aftershocks of the two earthquakes are distributed more than the stress-enhanced region or the boundary of the stress-increasing region and the stress-reducing region, and the maximum region of the stress increases. There is little aftershock distribution. The NE-trending stress growth zone in 1878 in the east of the South China Sea also covers the 1906 earthquake, which was triggered in 1906. The earthquake is more likely to be earthquake. In addition, the stress growth of earthquake SW in 1878 is arc-shaped and intersects with the epicenter of July 5, 1918. It is likely to be the triggering factor of the earthquake in 1918. In 1992, the seismic stress increasing area of Dongsha Islands is NE direction, the descent area is NW, and the aftershocks are distributed more than that of earthquake. In addition, the seismic stress growth area of Dongsha Islands covers the focal position of Taiwan shoal in 1994, and the former may be touch. The main factors of the latter are: (4) The east coast of the northern margin of the South China Sea is affected by the east-sand movement, and the high-pressure formation has a pressure relief, and the diapir structure does not develop, so that the transportation system of the gas source of the east natural gas hydrate is broken. The combination of layer-fault, while the west is affected by the east-sand movement is small, the diapir structure is very developed, so that the western part takes fault-diapir combined style as natural gas water. The main channel of gas source migration. (5) The new tectonic evolution of the continental margin in the northern South China Sea is influenced by the Pacific tectonic domain. The development characteristics of the continental margin faults in the northern South China Sea are different from the distribution locations. There are differences, which can be divided into two parts: east and west. In time scale, different tectonic domains are different. There are also differences in the range of influence in the northern South China Sea. From the Late Cretaceous to the Late Oligochaean (32Ma), the north of the South China Sea is affected by the Pacific tectonic domain. hardly influenced by the Tethys tectonic domain. The study of fracture activity shows that Miocene The Pearl River Mouth Basin is controlled by Tethys tectonic domain. The east began to be affected by the Pacific tectonic domain. After that, the convergence rate of the Pacific plate increased, and it was on the Pearl River. The influence of the mouth basin is gradually enlarged to the west.
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P736
本文编号：2279988
[Abstract]:As the largest marginal sea in the western Pacific Ocean, the South China Sea developed numerous Cenozoic basins, which contained abundant energy resources. In this paper, the new tectonic feature of the northern South China Sea is systematically and comprehensively studied by means of seismic section and focal mechanism solution. This is of great significance for understanding the dynamics mechanism of the new structure in the northern South China Sea, the formation of natural gas hydrate and the prevention and treatment of submarine geological disasters. Through the study, several conclusions are drawn: (1) The distribution of Cenozoic magmatic rocks in the northern South China Sea can be divided into three magmatic activity concentrations from east to west: southeast of Qiong-Xisha area, Fox area and east. The control factors of the output position of the magmatic rocks in each region are different, among which, the plane distribution of the magmatic rocks in the southeast-Xisha area of Qiong is controlled by the left-right-order slip-slip fault, and the rock-magmatic rocks in the Fox area are located at the junction of NW and NE trending faults, and the invaded space is subjected to pre-storage fracture. Constraints; the formation of magmatic rocks in the east sand area is directly related to the regional extension process during the east-sand movement. (2) According to the distribution characteristics of the earthquake, and combining with the solution of the focal mechanism, the continental margin of the South China Sea is also divided. There are three regions in the east. The eastern part of the Philippine Sea plate is strongly extruded along the NW direction of the Luzon island arc, the strong earthquakes have occurred many times, the seismic activity is strongest, the west is influenced by the strike-slip of the red river fault, and the seismic activity is high, but still There is a strong earthquake record; whereas in the eastern collision type and the middle position of the transition plate boundary in the west, the area of the Pearl River mouth, the seismic activity is very weak, far from the large earthquake, the strong earthquake occurs, and the small earthquake also The research on the solution of the focal mechanism shows that the earthquake in the north of the South China Sea is broken. The earthquake activity in the east is dominated by NE trending right, and the seismic activity in the middle part is controlled by normal fault, and the fault of the western seismogenic fault is NW trending right. The history of the east section, the middle section of the South China Sea and the east section of the South China Sea is simulated by Coulomb simulation. The stress field is simulated in the west of the South China Sea in 1936, which triggered the earthquake in the Beibu Gulf in 1988, and the aftershocks of the Qionshan earthquake in 1995 occurred in the region where the stress isolines developed slowly. Seismic development of the region after 1995, which resulted in the earthquake development of the region since 1995. In 1994, the magnitude 6 earthquake occurred in 1995 with stress reduction as the main aftershock. The aftershocks of the river source earthquake in the middle section of the South China Sea in 1962 are mainly developed at the NW end of the fault, and the aftershocks of the Yangjiang earthquake in 1969 On the north side of the fracture, the aftershocks of the two earthquakes are distributed more than the stress-enhanced region or the boundary of the stress-increasing region and the stress-reducing region, and the maximum region of the stress increases. There is little aftershock distribution. The NE-trending stress growth zone in 1878 in the east of the South China Sea also covers the 1906 earthquake, which was triggered in 1906. The earthquake is more likely to be earthquake. In addition, the stress growth of earthquake SW in 1878 is arc-shaped and intersects with the epicenter of July 5, 1918. It is likely to be the triggering factor of the earthquake in 1918. In 1992, the seismic stress increasing area of Dongsha Islands is NE direction, the descent area is NW, and the aftershocks are distributed more than that of earthquake. In addition, the seismic stress growth area of Dongsha Islands covers the focal position of Taiwan shoal in 1994, and the former may be touch. The main factors of the latter are: (4) The east coast of the northern margin of the South China Sea is affected by the east-sand movement, and the high-pressure formation has a pressure relief, and the diapir structure does not develop, so that the transportation system of the gas source of the east natural gas hydrate is broken. The combination of layer-fault, while the west is affected by the east-sand movement is small, the diapir structure is very developed, so that the western part takes fault-diapir combined style as natural gas water. The main channel of gas source migration. (5) The new tectonic evolution of the continental margin in the northern South China Sea is influenced by the Pacific tectonic domain. The development characteristics of the continental margin faults in the northern South China Sea are different from the distribution locations. There are differences, which can be divided into two parts: east and west. In time scale, different tectonic domains are different. There are also differences in the range of influence in the northern South China Sea. From the Late Cretaceous to the Late Oligochaean (32Ma), the north of the South China Sea is affected by the Pacific tectonic domain. hardly influenced by the Tethys tectonic domain. The study of fracture activity shows that Miocene The Pearl River Mouth Basin is controlled by Tethys tectonic domain. The east began to be affected by the Pacific tectonic domain. After that, the convergence rate of the Pacific plate increased, and it was on the Pearl River. The influence of the mouth basin is gradually enlarged to the west.
【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P736
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