【作者】 侯启军；

【导师】 钟建华； 赵政璋；

【作者基本信息】 中国科学院研究生院（广州地球化学研究所） ， 构造地质学， 2006， 博士

【摘要】 晚侏罗—早白垩世早期,松辽盆地北部深层断陷的发育经历了火石岭组的初始断裂期、沙河子组的强烈断陷期和营城组的断拗转化期。 沙河子组期控陷断裂的演化经历了由多个区段独立发育、相邻区段相互作用、进而通过一条新的断裂连为一条区域性断裂的过程。最初控陷断裂的各区段表现为北北西向断层的右阶雁列及北北东向断裂的左阶雁列,表现出明显的斜向伸展特征。最终控陷断裂系统在研究区内形成了安达—徐家围子这一北北西向的大规模断陷发育带。 从深层断陷的残留现状看,各条控陷断裂的演化程度参差不齐,演化程度较高的控陷断裂纵向上断距幅度大,平面上连续性强,沿走向断裂特征变化小,所控制的断陷规模大,结构明朗。演化程度较低的控陷断裂纵向上断距幅度小,平面上连续性差,沿走向断裂特征变化大,所控制的断陷规模小,断陷各个部分的分异性差,结构混沌。 控陷断裂的动态演化过程控制了深层断陷的动态发育。一个断陷的完整发育过程可划分为五个阶段,即胚胎期(象古龙—常家围子断陷)、幼年期(双城断陷)、成长期(莺山断陷)、成熟期(徐家围子断陷)、联合期断陷(安达—昌五断陷与徐家围子断陷已构成联合之势)。一个具体的断陷发育可终止于任何一个阶段,但高序次断陷的形成必须经历低序次断陷的发育过程,高序次断陷结构中也必然蕴含着低序次断陷的结构。包容在高序次断陷中的低序次断陷结构的原始特征虽已模糊,但不难在现存的低序次断陷中比较清晰地看到其原始特征。 松辽地区纵向上叠置了三个形成机制不同、边界条件不同的中新生代盆地,即火石岭—营城组时期的泛东北亚断陷群,登娄库—依安组时期的松辽大型拗陷盆地,新近纪以来盆岭伸展构造格架下的现今地理盆地。深层断陷盆地群与大型拗陷盆地之间曾发生过重大的区域性地质背景变革,并非象前人所称的那样,是一个继承性发育过程。断陷期地层遭受的规模较大的改造作用分别发生于大型拗陷盆地的孕育、发展和反转萎缩阶段。大型拗陷盆地孕育阶段的主要改造形迹为区域性挤压褶皱和剥蚀作用。大型拗陷盆地的沉降格局决定了断陷期地层的埋藏格局。大型拗陷盆地反转萎缩期研究区东部的断陷期地层全部卷入了区域性逆冲褶皱系统。 沙河子期的断陷原形控制了烃源岩的平面分布,沙河子组烃源岩的埋藏与剥蚀历史、保存与残留现状,从“源控型”的角度控制了天然气的平面分布。徐家围子断陷的徐西伸展断裂带、丰乐挠曲带、徐南凹陷和升平—兴城转换斜坡,以及茂兴断陷等是五个深层天然气成藏条件优越的勘探区带。更多还原

【Abstract】 From the Late Jurassic to the Early Cretaceous, the deep fault-depressions in North Songliao Basin had gone through three developing stages, the initial faulting stage during Huoshiling Period, the intense fault-subsiding stage during Shahezi Period, and the fault-depression depauperation stage during Yingcheng Period.All the depression-controlling faults in the deep in North Songliao Basin had generally gone through the dynamic processes from the independent development, interactional development, to the united development. The faults during the independent developing stage appeared as the en-echelon arrangements along NNW and NNE strike under the shear-extending. And finally, under the controlling of the depression-controlling faults in the deep in North Songliao Basin, there developed the great NNW strike fault-depression zone, An’da-Xujiaweizi fault-depression zone.The present characteristics show that the developing degrees of the depression-controlling faults are very different. The faults with the high developing degree are long, great in the vertical displacements, with the concordant characteristics along the strikes. And the fault-depressions controlled by the high-degree faults are generally very big. But the faults with the low developing degree always have the completely contrary characteristics from the high-degree faults.The dynamic developing faults controlled the dynamic developments of the depressions during Shahezi Stage during the Early Cretaceous. The present depression structures in North Songliao Basin show that the developing process of the entire depression generally goes through five phases: the embryo phase (such as Gulong-Changjiaweizi Fault-depression), the infancy phase (such as Shuangcheng Fault-depression), the youth phase (such as Yingshan Fault-depression), the adult phase (such as Xujiaweizi Fault-depression), and the united phase (such as Xujiaweizi Fault-depression and Anda-Changwu Fault-depression having been united together). Any fault-depression perhaps terminates at any developing phase. The high-phasefault-depressions always went through the low developing phase, and were always left with some imprints of the low-phase fault-depression. Although the original characteristics of the low-phase fault-depressions in the high-phase fault-depressions are difficult to be distinguished, the present low-phase fault-depression can show their original characteristics.In Songliao region, there developed three basins with the different formation mechanisms and different boundary conditions during the Mesozoic-Cenozoic, which are the fault-depression basin during Huoshiling-Yingcheng Period, the great depression basin during Denglouku-Yi’ an Period, and the present geographic basin under the basin-range extending since Neogene Period. Between the development period of the fault-depression basin and the great depression basin, the regional geologic setting changed revolutionarily, but not with the inherited development. There happened the major structural reformations on the deep formations during the gestation period, growth period, and the reversion-depauperization period of the great depression basin. The regional compressive folding and denudations happened during the gestation period. The subsiding during the growth period resulted in the burial patterns of the deep formations. During the reversion-depauperization period, the deep formations in the east were embroiled in the regional thrust-folding system.The fault-depression prototypes during Shahezi Stage controlled the distribution of the source rocks. According to the ’Source-controlling Theory’, the burying-denudating histories and present distributions of Shahezi source rocks controlled the distributions of the natural gas reservoirs. Xuxi Extending Fault Belt, Fengle Flexure Belt, Xunan Depression, Shengping-Xingcheng Transforming Slope, and Maoxing Fault-depression are the better exploration zones for the natural gas in the deep.更多还原