南海新生代构造演化及岩石圈三维结构特征
|
摘要
地震层析资料表明,南海地区,自红河口向南经南海、苏禄海到苏拉威西海,岩石圈速度低,底部横波速度仅4.4km/s,岩石圈厚度在60～80km之间,为薄岩石圈地区。软流层的速度也较低,在4.2～4.4km/s之间,但厚度较大,大于200km。从红河-莺歌海断裂带经南海到苏禄海,存在一条北西向宽约200km的上地幔北西向低速带,面波速度在4.05～4.25km/s之间。由上述资料可见,东亚大陆边缘及边缘海的上地幔存在一巨型低速带,在南海地区低速带的走向为北西向,在东海地区为北北西向。这种走向与地表的区域构造走向基本一致,反映这里新生代构造活动可能与地幔低速带分布有关,即上地幔低速带反映了岩石圈的区域流动。这类岩石圈区域流动引起岩石圈表层的张性构造,形成裂谷及稍后的海底扩张,在亚洲东部边缘形成一系列边缘海盆。
Seismic tomographic data indicate that the lithosphere velocity is low in the South China Sea region from the mouth of the Red River (Hong Ha River) through the South China Sea and Sulu Sea to Sulawesi Sea. The velocity of the transverse wave at the base of the lithosphere is only 4.4 km/s and the thickness of the lithosphere ranges from 60 to 80 km; so the region is the one with a thin lithosphere. The velocity of the asthenosphere is also relatively low, ranging from 4.2 to 4.4 km/s, but its thickness is great, >200 km. From the Red River-Yinggehai fault belt through the South China Sea to the Sulu Sea there exists a NW-trending, ～200 km wide, upper mantle low-velocity zone with a transverse wave velocity ranging from 4.05 to 4.25 km/s. The above-mentioned data suggest that there exists a gigantic low-velocity zone from the margin of the East Asian continent to marginal sea. It strikes NW in the South China Sea region and NNW in the East China Sea region. The approximate consistency of these strikes with those of the lineaments on the surface reflects that the Cenozoic tectonic activity there might be related to the distribution of the mantle low-velocity zone, i.e. the upper mantle low-velocity zone reflects the regional flow of the lithosphere, which gave rise to tensional tectonics in the superficial layer of the lithosphere and formed rifts and slightly later sea-floor spreading and a number of marginal sea basins on the eastern margin of Asia.
Seismic tomographic data indicate that the lithosphere velocity is low in the South China Sea region from the mouth of the Red River (Hong Ha River) through the South China Sea and Sulu Sea to Sulawesi Sea. The velocity of the transverse wave at the base of the lithosphere is only 4.4 km/s and the thickness of the lithosphere ranges from 60 to 80 km; so the region is the one with a thin lithosphere. The velocity of the asthenosphere is also relatively low, ranging from 4.2 to 4.4 km/s, but its thickness is great, >200 km. From the Red River-Yinggehai fault belt through the South China Sea to the Sulu Sea there exists a NW-trending, ～200 km wide, upper mantle low-velocity zone with a transverse wave velocity ranging from 4.05 to 4.25 km/s. The above-mentioned data suggest that there exists a gigantic low-velocity zone from the margin of the East Asian continent to marginal sea. It strikes NW in the South China Sea region and NNW in the East China Sea region. The approximate consistency of these strikes with those of the lineaments on the surface reflects that the Cenozoic tectonic activity there might be related to the distribution of the mantle low-velocity zone, i.e. the upper mantle low-velocity zone reflects the regional flow of the lithosphere, which gave rise to tensional tectonics in the superficial layer of the lithosphere and formed rifts and slightly later sea-floor spreading and a number of marginal sea basins on the eastern margin of Asia.
引文
[1]LudwigWJ.TheManilaTrenchandWestLuzonTrough:Seis-mic-refractionmeasurements[J].DeepSeaResearch,1970,17(3):27-45.
[2]LudwigWJ.Profiler-sonobuoymeasurementintheSouthChinaSeaBasin[J].J.G.R.,1979,84:3505-3518.
[3]YaoBochu,WangGuangyu.CrustalstructureoftheSouthChi-naSeaBasin[J].ScientiaSinica(B),1983,26(6):649-661.
[4]蔡学林,朱介寿,曹学敏,等.东亚西太平洋巨型裂谷体系岩石圈与软流圈结构及动力学[J].中国地质,2002,29(3):234-245.
[5]薛万俊.南海地貌图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[6]鲍才旺.南海地形图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[7]BenAvrahamZ,UyedaS.TheevolutionoftheChinaBasinandtheMesozoicPaleogeographyofBorneo[J].EarthandPlanet.Sci.Lett.,1973,18:365-375.
[8]TaylorB,HayesDE.ThetectonicevolutionoftheSouthChi-naSeaBasin[A].In:HayesDEed.ThetectonicandgeologicevolutionofSoutheastAsiaseasandislands[C].GeophysicalMonograph,AGU,Washington,1980,23:89-104.
[9]陈圣源.南海磁力异常图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[10]何廉声.南海地质构造图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[11]吕文正.南海中央海盆条带磁异常特征及构造]化[J].海洋学报,1987,9(1):69-78.
[12]姚伯初.南海海盆在新生代的构造]化[J].南海地质研究,1991,3:9-23.
[13]姚伯初,曾维军,等.中美合作调研南海地质专报[M].武汉:中国地质大学出版社,1994.75-90.
[14]姚伯初.南沙海槽的构造特征及其构造]化史[J].南海地质研究,1996,8:1-14.
[15]姚伯初.南海北部陆缘新生代构造运动初探[J].南海地质研究,1993,5:1-12.
[16]廖其林,王振明,李振江,等.福州—泉州—汕头地区地壳结构的爆炸地震研究[J].地球物理学报,1986,3(3):270-280.
[17]JacobsJA.DeepInterioroftheEarth[M].PrintedinGreatBritainbyPageBros,Norfolk,Chapman&Hall,1992.
[18]OlsonP,SilverPG,CarlsonRW.Thelarge-scalestructureofconvectionintheEarth'sMantle[J].Nature,1990,344:209.
[19]姚伯初.南海北部陆缘的地壳结构及构造意义[J].海洋地质与第四纪地质,1998,18(2):1-16.
[20]WangJiyang,etal.GeothermicsinChina[M].SeismologicalPress,Beijing,China,1996.
[2]LudwigWJ.Profiler-sonobuoymeasurementintheSouthChinaSeaBasin[J].J.G.R.,1979,84:3505-3518.
[3]YaoBochu,WangGuangyu.CrustalstructureoftheSouthChi-naSeaBasin[J].ScientiaSinica(B),1983,26(6):649-661.
[4]蔡学林,朱介寿,曹学敏,等.东亚西太平洋巨型裂谷体系岩石圈与软流圈结构及动力学[J].中国地质,2002,29(3):234-245.
[5]薛万俊.南海地貌图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[6]鲍才旺.南海地形图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[7]BenAvrahamZ,UyedaS.TheevolutionoftheChinaBasinandtheMesozoicPaleogeographyofBorneo[J].EarthandPlanet.Sci.Lett.,1973,18:365-375.
[8]TaylorB,HayesDE.ThetectonicevolutionoftheSouthChi-naSeaBasin[A].In:HayesDEed.ThetectonicandgeologicevolutionofSoutheastAsiaseasandislands[C].GeophysicalMonograph,AGU,Washington,1980,23:89-104.
[9]陈圣源.南海磁力异常图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[10]何廉声.南海地质构造图[A].见:南海地质地球物理图集[M].广州:广东科技出版社,1987.
[11]吕文正.南海中央海盆条带磁异常特征及构造]化[J].海洋学报,1987,9(1):69-78.
[12]姚伯初.南海海盆在新生代的构造]化[J].南海地质研究,1991,3:9-23.
[13]姚伯初,曾维军,等.中美合作调研南海地质专报[M].武汉:中国地质大学出版社,1994.75-90.
[14]姚伯初.南沙海槽的构造特征及其构造]化史[J].南海地质研究,1996,8:1-14.
[15]姚伯初.南海北部陆缘新生代构造运动初探[J].南海地质研究,1993,5:1-12.
[16]廖其林,王振明,李振江,等.福州—泉州—汕头地区地壳结构的爆炸地震研究[J].地球物理学报,1986,3(3):270-280.
[17]JacobsJA.DeepInterioroftheEarth[M].PrintedinGreatBritainbyPageBros,Norfolk,Chapman&Hall,1992.
[18]OlsonP,SilverPG,CarlsonRW.Thelarge-scalestructureofconvectionintheEarth'sMantle[J].Nature,1990,344:209.
[19]姚伯初.南海北部陆缘的地壳结构及构造意义[J].海洋地质与第四纪地质,1998,18(2):1-16.
[20]WangJiyang,etal.GeothermicsinChina[M].SeismologicalPress,Beijing,China,1996.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心