摘要
已经利用近垂直反射地震叠偏剖面得到太平洋板块西向俯冲远程应力场形成上部地壳滑脱断裂的证据,在此基础上,利用油气地震叠偏剖面发现中远程的蒙古鄂霍茨克缝合带、远程的太平洋板块西向俯冲带在松辽盆地滨北地区浅部基底共同作用形成的逆冲推覆断裂系统.该断裂系统基本呈双向形式,纵向与横向上表现出不均匀的强度,向西逆冲推覆的断裂系统厚度范围可达到约3~4 km,向东的断裂系统厚度范围可达到约1~2 km,断裂系统组构比较复杂.经过对控盆断裂孙吴双辽断裂两侧地球物理场分布特征的分析,认为松辽盆地浅部基底的逆冲推覆断裂系统是叠加在孙吴—双辽断裂之上的新的断裂系统.考虑到蒙古鄂霍茨克缝合带在远离1000多公里之外所产生的内蒙古阴山—燕山大型逆冲推覆断裂带以及松辽盆地的区域构造位置,认为在松辽盆地南部和滨北地区孙吴双辽断裂构造线之外也应该存在浅部基底内的逆冲推覆断裂.
Nearly vertical seismic reflection stacked migration section study has proved that the distant stress field formed by the westward subduction of Pacific plate lead to the detachment of upper crust.In the upper basement of Songliao basin in Binbei area,the thrust-nappe fault system was controlled by middle-distance Mongolia-Okhotsk suture zone and distant westward subduction of Pacific plate together.The fault system shows bidirection and the asymmetric intensity shows in longitudinal and transverse directions.The thickness is 3~4 km and 1~2 km for the westward thrust-nappe fault system and the eastward fault system,respectively.The structure of fault system is complex.According to the distribution of geophysical field along both sides of the Sunwu-Shuangliao fault which controlled the evolution of the basin,the thrust-nappe fault system in the upper basement of Songliao basin was overlapped on the Sunwu-Shuangliao fault.As we know,the Mongolia-Okhotsk suture zone has formed the huge Yinshan-Yanshan thrust-nappe zone more than 1000 km far away from the suture zone.Taking this and the regional tectonic environment of Songliao basin into account,a thrust-nappe fault system should be formed in the south Songliao basin and the Binbei area beyond the Sunwu-Shuangliao fault system.
引文
1) 大庆油田有限责任公司勘探开发研究院.松辽盆地滨北油气地质综合研究及勘探目标选择(内部资料).2005
[1] 郑亚东,王士政,王玉芳.中蒙边界区新发现的特大型推覆构造及伸展变质核杂岩.中国科学(B辑),1990,20(12) :1299~1305Zheng Y D,Wang S Z,Wang Y F.The new discovery of mega thrusting tectonics and Metamorphic Core Complexes in the boundary of China and Mongolia.Science in China,Ser.B(in Chinese),1990,20(12) :1299~1305
[2] 郑亚东,Davis G A,王琮等.内蒙古大青山大型逆冲推覆构造.中国科学(D辑),1998,28(4) :289~295Zheng Y D,Davis G A,Wang Z,et al.Study on Daqingshan mega thrusting tectonics in Inner Mongolia.Science in China,Ser.D(in Chinese),1998,28(4) ,289~295
[3] Davis G A,Zheng Y,Zhang J.The enigmatic Yinshan fold-and-thrust belt of northern China:new views on its intraplate contractional styles.Geology,1998,26:43~46
[4] Wang P J,Xie X A,Mattern F,et al.The cretaceous Songliao basin:Volcanogenic succession,sedimentary sequence and tectonic evolution,NE China.Acta Geologica Sinica(English Edition),2007,81(6) :1002~1011
[5] 杨宝俊,穆石敏,金旭等.中国满洲里-绥芬河地学断面地球物理综合研究.地球物理学报,1996,39(6) :772~782Yang B J,Mu S M,Jin X,et al.Synthesized study on the geophysics of Manzhouli-Suifenhe geoscience transect,China.Chinese J.Geophys.(in Chinese),1996,39(6) :772~782
[6] Yang B J,Liu C,Han L G,et al.A study of detachment faults of the upper crust in Manzhouli-Suifenhe GGT by the method of vertical seismic reflection.Liu G D ed.Proceedings of the 30th International Geology Congress.Vol.20,Geophysics.VSP BV The Netherlands,1997. 51~61
[7] 王玉净,樊志勇.内蒙古西拉木伦河北部蛇绿岩带中二叠纪放射虫的发现及其地质意义.古生物学报,1997,36(1) :58~69Wang Y J,Fan Z Y.Discovery of Permian radiolarians in ophiolite belt on northern side of Xar Moron River,Nei Monggol and its geological significance.Cta Palaeontologica Sinica(in Chinese),1997,36(1) :58~69
[8] Hilde T W C,Uyeda S,Kroenke L.Evolution of the Western Pacific and its margin.Tectonophysics,1977,38(1-2) :145~165
[9] Maruyama S,Seno T.Orogeny and relative plate motions:Example of the Japanese Islands.Tectonophysics,1986,127(3-4) :305~329
[10] Kinoshita O.Migration of igneous activities related to ridge subduction in Southwest Japan and the East Asian continental margin from the Mesozoic to the Paleogene.Tectonophysics,1995,245:25~35
[11] Khudololey A K,Sokolov S D.Structural evolution of the northeast Asia continental margin:an example from the western Koryak fold and thrust belt(northeast Russia).Geol Mag,1998,135:311~330
[12] 宁杰远,臧绍先.日本海及中国东北地震的深度分布及其应力状态.地震地质,1987,9(2) :49~64Ning J Y,Zang S X.The distribution of earthquakes and stress state in the Japan Sea and the northeast China.Seismology and Geology(in Chinese),1987,9(2) :49~64
[13] Maruyama S.Plume Tectonics.Jour.Geol.Soc.Japan,1994,100(1) :24~29
[14] 杨宝俊,张梅生,王璞珺.中国油气区地质-地球物理解析(上卷).北京:科学出版社,2003Yang B J,Zhang M S,Wang P J.Geological-Geophysical Analytic Interpretation on Oil and Gas Potential Region of China(Vol.1) (in Chinese).Beijing:Science Press,2003