青藏高原北缘基底结构的有限差分研究
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摘要
拜城-大柴旦综合地球物理剖面横跨了塔里木盆地、阿尔金造山带和柴达木盆地.沿剖面进行了10次各2吨级TNT炸药的人工地震探测工作.本文利用沿剖面的Pg震相,使用有限差分方法对塔里木盆地、阿尔金造山带和柴达木盆地的基底顶界面埋深及盖层的速度结构进行了反演,结果表明,不同的地质构造单元具有不同的基底结构形态与速度分布特点.塔里木盆地的基底及盖层速度分布相对平稳,表现出整体变形特征,但在库车与轮台之间,盆地的基底埋深及速度分布发生了明显的变化,深度差约2 km,速度差高达0.5 km/s.这种明显的、系统的速度差异,加之其它地质学与深部地球物理学证据表明,塔里木盆地的基底可能由构造特点不同的东西两个部分构成;阿尔金造山带的基底埋深与盖层速度分布变化较大,与造山带的强烈构造变形相联系;在阿尔金造山带与塔里木盆地和柴达木盆地的接触部位基底及盖层介质均表现为高速异常,可能与深部高密度物质沿断裂向地壳内部迁移有关;柴达木盆地的基底与盖层呈"U"形分布,表现出强烈的内部变形特征.
The comprehensive geophysical profile from Baicheng to Da Qaidam runs through the Tarim Basin、the Altyn Tagh Range and the Qaidam Basin.Ten chemical explosions with 2 ton TNT and receptions were carried out along the profile.Making use of Pg phases and finite difference method,the inversion on the structure of the basement and deposit cover of the Tarim Basin、the Altyn Tagh Range and the Qaidam Basin was conducted.The results demonstrate that different tectonic unit has different velocity distribution and structural character: The velocity distribution of the basement and deposit cover of the Tarim Basin is relatively balanced,showing an integrated deformation style of the basin.However,an obvious change of the basement and the deposited cover occurred in between Kuqa and Luntai,with a depth change of 2 km and velocity contrast of 0.5km/s.This obvious and systemic change in depth and velocity indicates that the basement of the Tarim Basin may be divided into two parts-the eastern part and the western one,combined with other geological and geophysical evidence.The velocity distribution of the basement and deposited cover of the Altyn Tagh Range appears as a biggish undulation,which may be related to strong tectonic deformation of the orogenic belt.Two high velocity zones were found at the boundaries between the Altun Tagh Range and the two basins at its both sides,indicating that the high density mass in the deep parts moves upward to the inner crust along the faults.The basement of the Qaidam Basin looks like a fovea,which has a character of intensive deformation.
The comprehensive geophysical profile from Baicheng to Da Qaidam runs through the Tarim Basin、the Altyn Tagh Range and the Qaidam Basin.Ten chemical explosions with 2 ton TNT and receptions were carried out along the profile.Making use of Pg phases and finite difference method,the inversion on the structure of the basement and deposit cover of the Tarim Basin、the Altyn Tagh Range and the Qaidam Basin was conducted.The results demonstrate that different tectonic unit has different velocity distribution and structural character: The velocity distribution of the basement and deposit cover of the Tarim Basin is relatively balanced,showing an integrated deformation style of the basin.However,an obvious change of the basement and the deposited cover occurred in between Kuqa and Luntai,with a depth change of 2 km and velocity contrast of 0.5km/s.This obvious and systemic change in depth and velocity indicates that the basement of the Tarim Basin may be divided into two parts-the eastern part and the western one,combined with other geological and geophysical evidence.The velocity distribution of the basement and deposited cover of the Altyn Tagh Range appears as a biggish undulation,which may be related to strong tectonic deformation of the orogenic belt.Two high velocity zones were found at the boundaries between the Altun Tagh Range and the two basins at its both sides,indicating that the high density mass in the deep parts moves upward to the inner crust along the faults.The basement of the Qaidam Basin looks like a fovea,which has a character of intensive deformation.
引文
[1]刘光鼎.中国大陆构造格架的动力学演化[J].地学前缘,2007,14(3):39~46.Liu G D.Geodynamic evolution and tectonic framework ofChina[J].Earth Science Frontiers,2007,14(3):39~46.
[2]任纪舜,陈延愚,牛宝贵,等.中国东部及邻区大陆岩石圈的构造演化与成矿[M].北京:科学出版社,1990.Ren J S,Chen Y Y,Niu B G,et al.The tectonic evolution ofcontinental lithosphere and Mineral Resources in Eastern Partof China and Its Adjacent Regons[M].Beijing:Science Press,1990.
[3]金之钧,王清晨.中国典型叠合盆地与油气成藏研究新进展[J].中国科学,2004,34(增刊):1~12.Jin Z J,Wang Q C.Recent development in study of the typicalsuperimposed basins and petroleum in China:Exemplified bythe Tarim Basin.Sciences in China Ser[J].D Earth Sciences2004,34(Supp.):1~12.
[4]马宗晋,杜品仁,洪汉净.地球构造与动力学[M].广州:广东科技出版社,2003.Ma Z J,Du P R,Hong H J.Global Tectonics and Geodynam-ics[M].Guangdong:Science and Technology Press,2003.
[5]滕吉文.柴达木东盆地的深层地震反射波和地壳构造[J].地球物理学报,1974,17(2):122~135.Teng J W.Deep seismic reflection wave and crustal sructure inthe east Qaidam basin[J].Acta Geophysica Sinica,1974,17(2):122~135.
[6]刘光鼎,郝天珧,刘伊克,等.中国大地构造宏观格架及其与矿产资源的关系[J].科学通报,1997,42(2):113~118.Liu G D,Hao T Y,Liu Y K,et al.Macroscopic geotectonicframework and its relation to mineral resources in China[J].Chinese Science Bulletin,1997,42(2):113~118.
[7]滕吉文,杨立强,姚敬全,等.金属矿产资源的深部找矿、勘探与成矿的深层动力过程[J].地球物理学进展,2007,22(2):317~334.Teng J W,Yang L Q,Yao J Q,et al.Deep discover ore,ex-ploration and exploitation for metal mineral resources and itsdeep dynamical process of formation.Progress in Geophysics,2007,22(2):317~334.
[8]周新源,罗金海,王清华.塔里木盆地南缘冲断带构造特征及其油气地质特征[J].中国科学D辑地球科学2004,34(增刊I):56~62.Zhou X Y,Luo J H,Wang Q H.Structural features and pe-troleum geology of the fold-thrust belt in the southern Tarimbasin,China[J].Sciences in China Ser.D Earth Sciences,2004,34(Supp.I):56~62.
[9]肖序常,汤耀庆,李锦轶,等.试论新疆北部大地构造演化[M].新疆地质科学,北京:地质出版社,1990(1):47~68.Xiao X C,Tang Y Q,Li J Y,et al.On the tectonic evolutionof the Northern Xinjiang[M].Geoscience of Xinjiang,Beijing:Geological Press,1990(1):47~68.
[10]刘训,肖序常.中国新疆南部(青藏高原北缘)盆山构造格局的演化[M].北京:地质出版社.2006.Liu X,Xiao X C.The evolution of the basin and range tec-tonic pattern of the southern Xinjiang,China(the northernmargin of the Tibetan Plateau)[M].Beijing:GeologicalPress,2006.
[11]赵俊猛.天山造山带与准噶尔盆地岩石圈结构及其动力学过程[D].中国地震局地质研究所,北京,1998.Zhao J M.Lithospheric structure and geodynamic processesof the Tianshan orogenic belt and the Junggar basin[D].Bei-jing:Institute of Geology,China Seismological Bureau,1998.
[12]Wang E,Xu F Y,Zhou J X,Wan J L,Burchfiel B C.East-ward migration of the Qaidam basin and its implication forCenozoic evolution of the Altyn Tagh fault and associated riv-er systems[J].Geological society of america bulletin,2006,118(3-4):349~365.
[13]贾承造.中国塔里木盆地构造特征与油气[MJ].北京:石油工业出版社.1997.Jia C Z.Tectonic Characteristics and Hydrocarbon of TarimBasin of China[M].Beijing:Petroleum Industry Press,1997.
[14]张恺,高明远,姚惠君,等.中国大陆板块构造与含油气盆地.见:《中国含油气区构造特征》编委会.中国含油气区构造特征[M].北京:石油工业出版社,1989.20~34.Zhang K,Gao M Y,Yao H J,et al.Tectonics of Chinesecontinental plate and petroliferous basin(Editorial Committeeof Tectonic Characteristics of Chinese Petroliferous Area).Tectonic Characteristics of Chinese Petroliferous Area[M].Beijing:Petroleum Industry Press,1989.20~34.
[15]庞雄奇,金之钧,姜振学,等.叠合盆地油气资源评价问题及其研究意义[J].石油勘探与开发,2002,29(1):9~13.Pang X Q,Jin Z J,Jiang Z X,et al.Evolution of hydrocar-bon resource in superimposed basin and its significance[J].Petroleum Exploration and Development,2002,29(1):9~13.
[16]林畅松,王清华,肖建新等.库车坳陷白恶纪沉积层序构成及充填响应模式[J].中国科学D辑地球科学2004,34(增刊I):74~82.Lin C S,Wang Q H,Xiao J X,et al.Depositional sequencearchitecture and filling response model of the Cretaceous inthe Kuqa depression,the Tarim basin[J].Sciences in ChinaSer.D Earth Sciences 2004,34(Supp.I):74~82.
[17]曾融生,何传大,阚荣举.柴达木盆地低频地震探测的”回折波”和多次波[J].地球物理学报,1961,10(1):39~53.Zeng R S,He C D,Kan R J.Refracted waves and multiplewaves in Qaidam basin by low-frequency seismic refraction meth-od[J].Chinese Journal of Geophysics 1961,10(1):39~53.
[18]高锐,李廷栋,吴功建.青藏高原岩石圈演化与地球动力学过程--亚东-格尔木-额济纳旗地学断面的启示[J].地质评论,1998,44(4):389~395.Gao R,Li T D,Wu G J.Lithospheric evolution and geody-namic process of the Qinghai-Tibet plateau:An inspirationfrom the Yadong-Golmud geoscience transect[J].GeologicalReview,1998,44(4):389~395.
[19]Zhao J M,Jin Z J,Wang S X,et al.CrustalStructure of thecentral qaidam[J].Basin imaged by seismic wide angler reflec-tion/refraction profiling.(submitted to J.G.R.).
[20]Wang E,Xu FY,Zhou JX,et al.Eastward migration of theQaidam basin and its implications for Cenozoic evolution ofthe Altyn Tagh fault and associated river systems[J].Geo-logical society of america bulletin,2006,(3-4):349~365.
[21]张先康,赵金仁,张成科,等.帕米尔东北侧地壳结构研究[J].地球物理学报,2002,37(6):356~365.Zhang X K,Zhao J R,Zhang C K,et al.Research on crus-tal structure of northeastern Pami[J].Chinese Journal of Ge-ophysics,2002,37(6):356~365.
[22]Zhao J M,Zhang X K,Ma Z J.The Crystalline basementand the property of the junggar basin and its development andevolution J.G..R.(in review).
[23]Zhao J M,Walter D M,Zhang X K,et al.Crustal structureacross the Altyn Tagh Range at the northern margin of theTibetan plateau and tectonic implications[J].Earth and Plan-etary Science Letter,2006,241(2006)804~814.
[24]Zhao J M,Liu G D,Lu Z X,et al.Lithospheric structureand dynamic processes of the Tianshan orogenic belt and theJunggar basin[J].Tectonophysics.376(2003)199~239.
[25]Zhao J M,Liu H B,Pei S P,et al.A geophysical transect ofthe lithosphere across the eastern tianshan orogen.Tectonics(in review).
[26]Hole J A,Zelt B C.3-D finite-difference reflection traveltimes[J].Geophys.J.Int,1995,121:427~434.
[27]段永红,张先康,方盛明.华北地区上部地壳结构的三维有限差分层析成像[J].地球物理学报,2002.45(3):362~369.Duan Y H,Zhang X K,Fang S M.Teree-dimensional finite-difference tomography of velocity structure of the ipper crus-tal in north China[J].Chinese J.Geophys.2002,45(3):362~369.
[28]徐朝繁,张先康,朱金芳,等.复杂介质结构中折射界面的哈格多恩原理波前成像[J].地震地质,2002,24(4):542~548.Xu Z F,Zhang X K,Zhu J F,et al.Refractor wavefront im-aging in terms of Hagedoorn principle in complex structure[J].Seismology and Geology,2002,24(4):524~548.
[2]任纪舜,陈延愚,牛宝贵,等.中国东部及邻区大陆岩石圈的构造演化与成矿[M].北京:科学出版社,1990.Ren J S,Chen Y Y,Niu B G,et al.The tectonic evolution ofcontinental lithosphere and Mineral Resources in Eastern Partof China and Its Adjacent Regons[M].Beijing:Science Press,1990.
[3]金之钧,王清晨.中国典型叠合盆地与油气成藏研究新进展[J].中国科学,2004,34(增刊):1~12.Jin Z J,Wang Q C.Recent development in study of the typicalsuperimposed basins and petroleum in China:Exemplified bythe Tarim Basin.Sciences in China Ser[J].D Earth Sciences2004,34(Supp.):1~12.
[4]马宗晋,杜品仁,洪汉净.地球构造与动力学[M].广州:广东科技出版社,2003.Ma Z J,Du P R,Hong H J.Global Tectonics and Geodynam-ics[M].Guangdong:Science and Technology Press,2003.
[5]滕吉文.柴达木东盆地的深层地震反射波和地壳构造[J].地球物理学报,1974,17(2):122~135.Teng J W.Deep seismic reflection wave and crustal sructure inthe east Qaidam basin[J].Acta Geophysica Sinica,1974,17(2):122~135.
[6]刘光鼎,郝天珧,刘伊克,等.中国大地构造宏观格架及其与矿产资源的关系[J].科学通报,1997,42(2):113~118.Liu G D,Hao T Y,Liu Y K,et al.Macroscopic geotectonicframework and its relation to mineral resources in China[J].Chinese Science Bulletin,1997,42(2):113~118.
[7]滕吉文,杨立强,姚敬全,等.金属矿产资源的深部找矿、勘探与成矿的深层动力过程[J].地球物理学进展,2007,22(2):317~334.Teng J W,Yang L Q,Yao J Q,et al.Deep discover ore,ex-ploration and exploitation for metal mineral resources and itsdeep dynamical process of formation.Progress in Geophysics,2007,22(2):317~334.
[8]周新源,罗金海,王清华.塔里木盆地南缘冲断带构造特征及其油气地质特征[J].中国科学D辑地球科学2004,34(增刊I):56~62.Zhou X Y,Luo J H,Wang Q H.Structural features and pe-troleum geology of the fold-thrust belt in the southern Tarimbasin,China[J].Sciences in China Ser.D Earth Sciences,2004,34(Supp.I):56~62.
[9]肖序常,汤耀庆,李锦轶,等.试论新疆北部大地构造演化[M].新疆地质科学,北京:地质出版社,1990(1):47~68.Xiao X C,Tang Y Q,Li J Y,et al.On the tectonic evolutionof the Northern Xinjiang[M].Geoscience of Xinjiang,Beijing:Geological Press,1990(1):47~68.
[10]刘训,肖序常.中国新疆南部(青藏高原北缘)盆山构造格局的演化[M].北京:地质出版社.2006.Liu X,Xiao X C.The evolution of the basin and range tec-tonic pattern of the southern Xinjiang,China(the northernmargin of the Tibetan Plateau)[M].Beijing:GeologicalPress,2006.
[11]赵俊猛.天山造山带与准噶尔盆地岩石圈结构及其动力学过程[D].中国地震局地质研究所,北京,1998.Zhao J M.Lithospheric structure and geodynamic processesof the Tianshan orogenic belt and the Junggar basin[D].Bei-jing:Institute of Geology,China Seismological Bureau,1998.
[12]Wang E,Xu F Y,Zhou J X,Wan J L,Burchfiel B C.East-ward migration of the Qaidam basin and its implication forCenozoic evolution of the Altyn Tagh fault and associated riv-er systems[J].Geological society of america bulletin,2006,118(3-4):349~365.
[13]贾承造.中国塔里木盆地构造特征与油气[MJ].北京:石油工业出版社.1997.Jia C Z.Tectonic Characteristics and Hydrocarbon of TarimBasin of China[M].Beijing:Petroleum Industry Press,1997.
[14]张恺,高明远,姚惠君,等.中国大陆板块构造与含油气盆地.见:《中国含油气区构造特征》编委会.中国含油气区构造特征[M].北京:石油工业出版社,1989.20~34.Zhang K,Gao M Y,Yao H J,et al.Tectonics of Chinesecontinental plate and petroliferous basin(Editorial Committeeof Tectonic Characteristics of Chinese Petroliferous Area).Tectonic Characteristics of Chinese Petroliferous Area[M].Beijing:Petroleum Industry Press,1989.20~34.
[15]庞雄奇,金之钧,姜振学,等.叠合盆地油气资源评价问题及其研究意义[J].石油勘探与开发,2002,29(1):9~13.Pang X Q,Jin Z J,Jiang Z X,et al.Evolution of hydrocar-bon resource in superimposed basin and its significance[J].Petroleum Exploration and Development,2002,29(1):9~13.
[16]林畅松,王清华,肖建新等.库车坳陷白恶纪沉积层序构成及充填响应模式[J].中国科学D辑地球科学2004,34(增刊I):74~82.Lin C S,Wang Q H,Xiao J X,et al.Depositional sequencearchitecture and filling response model of the Cretaceous inthe Kuqa depression,the Tarim basin[J].Sciences in ChinaSer.D Earth Sciences 2004,34(Supp.I):74~82.
[17]曾融生,何传大,阚荣举.柴达木盆地低频地震探测的”回折波”和多次波[J].地球物理学报,1961,10(1):39~53.Zeng R S,He C D,Kan R J.Refracted waves and multiplewaves in Qaidam basin by low-frequency seismic refraction meth-od[J].Chinese Journal of Geophysics 1961,10(1):39~53.
[18]高锐,李廷栋,吴功建.青藏高原岩石圈演化与地球动力学过程--亚东-格尔木-额济纳旗地学断面的启示[J].地质评论,1998,44(4):389~395.Gao R,Li T D,Wu G J.Lithospheric evolution and geody-namic process of the Qinghai-Tibet plateau:An inspirationfrom the Yadong-Golmud geoscience transect[J].GeologicalReview,1998,44(4):389~395.
[19]Zhao J M,Jin Z J,Wang S X,et al.CrustalStructure of thecentral qaidam[J].Basin imaged by seismic wide angler reflec-tion/refraction profiling.(submitted to J.G.R.).
[20]Wang E,Xu FY,Zhou JX,et al.Eastward migration of theQaidam basin and its implications for Cenozoic evolution ofthe Altyn Tagh fault and associated river systems[J].Geo-logical society of america bulletin,2006,(3-4):349~365.
[21]张先康,赵金仁,张成科,等.帕米尔东北侧地壳结构研究[J].地球物理学报,2002,37(6):356~365.Zhang X K,Zhao J R,Zhang C K,et al.Research on crus-tal structure of northeastern Pami[J].Chinese Journal of Ge-ophysics,2002,37(6):356~365.
[22]Zhao J M,Zhang X K,Ma Z J.The Crystalline basementand the property of the junggar basin and its development andevolution J.G..R.(in review).
[23]Zhao J M,Walter D M,Zhang X K,et al.Crustal structureacross the Altyn Tagh Range at the northern margin of theTibetan plateau and tectonic implications[J].Earth and Plan-etary Science Letter,2006,241(2006)804~814.
[24]Zhao J M,Liu G D,Lu Z X,et al.Lithospheric structureand dynamic processes of the Tianshan orogenic belt and theJunggar basin[J].Tectonophysics.376(2003)199~239.
[25]Zhao J M,Liu H B,Pei S P,et al.A geophysical transect ofthe lithosphere across the eastern tianshan orogen.Tectonics(in review).
[26]Hole J A,Zelt B C.3-D finite-difference reflection traveltimes[J].Geophys.J.Int,1995,121:427~434.
[27]段永红,张先康,方盛明.华北地区上部地壳结构的三维有限差分层析成像[J].地球物理学报,2002.45(3):362~369.Duan Y H,Zhang X K,Fang S M.Teree-dimensional finite-difference tomography of velocity structure of the ipper crus-tal in north China[J].Chinese J.Geophys.2002,45(3):362~369.
[28]徐朝繁,张先康,朱金芳,等.复杂介质结构中折射界面的哈格多恩原理波前成像[J].地震地质,2002,24(4):542~548.Xu Z F,Zhang X K,Zhu J F,et al.Refractor wavefront im-aging in terms of Hagedoorn principle in complex structure[J].Seismology and Geology,2002,24(4):524~548.
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