摘要
中国东北地区大兴安岭西侧盆地群包括漠河盆地、根河盆地、拉布达林盆地、海拉尔盆地和二连盆地等,蕴藏着丰富的中、新生代油气资源.为研究该盆地群域古生代、中新生代构造演化,综合建立盆地群域地球动力学模型,补充东北亚构造演化理论,本文综述该盆地群域受控的区域构造与深部构造背景、盆地群构造特征与性质、主要控盆断裂特征、盆地群油气条件比较以及盆地群域已完成并取得重要结果的地球物理工作.归纳已有主要认识和研究结果:(1)对大兴安岭西侧的盆地群起构造控制作用的构造带包括蒙古—鄂霍茨克洋缝合带、西拉木伦河缝合带、黑河—贺根山缝合带、塔原—喜桂图缝合带、西太平洋板块俯冲带,以及额尔古纳—呼伦断裂和得尔布干断裂.(2)二连盆地、海拉尔盆地和漠河盆地的盆地构造轴向与蒙古—鄂霍茨克洋缝合带走向相关;而且三个盆地内的一级构造单元走向(隆起、坳陷和推覆带)也具有这类特点.(3)几个地学断面的综合地球物理研究表明,大兴安岭西侧盆地群岩石圈地幔厚度自北向南变厚,南部盆地基底与华北地台基底表现类似;盆地群基底电性结构因受到软流圈热物质作用可能在继续演化.(4)在盆地沉积地层方面,漠河盆地的下部是侏罗系陆相煤系地层,上部是白垩系火山岩地层;海拉尔盆地由下侏罗统的铜钵庙组、南屯组,上侏罗统的大磨拐河组和下白垩统的伊敏组共同组成扎赉诺尔群,厚约3000m;二连盆地中生代地层中,中下侏罗统主要为含煤建造,上侏罗统为火山岩建造,下白垩统主要为含油建造和含煤建造,上白垩统为砂砾岩建造.(5)盆地群整体勘探程度较低.基于上述研究结果,需要进一步研究的科学问题包括:由本研究区的地球物理、构造地质、石油地质等多学科的综合研究,解决研究区受控的区域构造应力场所包括的因素及其作用,以及在岩石圈尺度上三维空间的地球物理场表征;深部构造对盆地群域构造的作用;从晚古生代到中新生代研究区构造演化特点及其依据;从北至南约1650km长的盆地群域构造差异与依据;盆地群(域)油气条件与毗邻的松辽盆地在构造成因上的差异.
The basin group west of the Da Hinggan Mountains in Northeast China includes Moh,Genhe,Labudalin,Hailaer and Erlian features,which host abundant Meso-Cenozoic oil and gas resources.In this paper,we summarize the regional and deep tectonic background,structure characteristics and properties,characteristics of basin-controlling faults,comparison of oil and gas conditions of the basins,and main geophysical work and results in these basins.The conslucions are as follows:(1)Tectonic controls for the basin group include the Mongolia-Okhotsk suture zone,Xar Moron River suture zone,Heihe-Hegenshan suture zone,Tayuan-Xiguitu suture zone,subduction zone of the West Pacific plate and Deerbugan fault.(2)The structural axes of the Erlian,Hailaer,and Mohe basins are related to the suture zone of Mongolian-okhotsk.Moreover,the trends of the primary tectonic units(uplifts,depressions and nappe belts)of the three basins show the same characteristics.(3)The comprehensive geophysical study of several GGTs shows that the mantle thickness of the basin group west of the Da Hinggan Mountains increases from north to south,and the basement of the south basin is similar to the base of North China.The electrical structure of the basement is probably to continue to evolve due to the magma of the asthenosphere.(4)In the sedimentary strata,the lower part of Mohe basin is the Jurassic continental coal stratum,and the upper part is the Cretaceous volcanic stratum.The Hailaer basin is composed of the Tongbomiao Formation of the Lower Jurassic and the Nantun Formation,Damoguaihe Formation of the upper Jurassic and the lower Cretaceous are composed of Zhalainuoer Group with a thickness of about 3000 m.In the Mesozoic strata of the Erlian basin,the middle and lower Jurassic are mainly coal-bearing formations,and the upper Jurassic is volcanic rock formation.The lower Cretaceous is mainly oil-bearing and coal bearing-formations,and the upper Cretaceous is glutenite formation.(5)The exploration of these basins are insufficient in general.Based on the above summarization,this paper raises some scientific problems that need further study:Understand the factors and their functions involved in the field of regional tectonic stress and characterize the earth's three-dimensional space on a lithosphere scale based on a comprehensive study of geophysics,tectonic geology,and petroleum geology in this area.Describe the effects of deep structure on that of the basin group.The characteristics and evidence of tectonic evolution from late Paleozoic to Mesozoic and Cenozoic.The tectonic difference and evidenc along the north-south 1650 km-long profile through the basin group.Differences in tectonic genesis of oil and gas conditions between the basin group and the neighboring Songliao basin.