【作者】 单伟；

【导师】 刘少峰；

【作者基本信息】 中国地质大学（北京） ， 构造地质学， 2009， 博士

【摘要】 论文以全球板块构造活动论、地质历史发展的地区性和阶段性等基本理论观点为指导思想,运用现代构造地质学和盆地分析的新概念、新方法,通过野外地质研究、火山岩特征、地震剖面、钻井和测井资料综合研究,讨论位于松辽裂谷南部的长岭地区断陷层盆地的几何学、运动学和地球动力学特征,揭示了白垩纪早期长岭地区断陷盆地的构造演化过程、阐述了松南地区断陷盆地伸展过程中地壳应变机制的差异。长岭凹陷白垩至今发育的地层可划分为三个构造层。底部断陷层可划分为四个组,自下而上分别是:火石岭组、沙河子组、营城组、登娄库组,代表了白垩纪早期不同阶段的沉积。断拗转换界面位于登娄库组内S1-4-2、S1-4-3层序之间。断陷层构造层序中发育了与裂陷背景相关的沉积体系类型,如扇三角洲、辫状河三角洲、冲积扇、辫状河冲积平原及湖泊沉积体系等,它们在空间上有机配置,反映了裂谷盆地的正断层边缘和缓坡边缘分别对盆地沉积体系发育的控制作用。断陷层切入基地的控盆断裂存在两个主展布方向:NE向和NW向。地震剖面平衡恢复的结果显示盆地过程中的伸展方向存在自NE向至近E-W向的顺时针旋转。初期火石岭期,伸展方向为NE向,沉降中心沿NW向展布形成三条沉降带。随后沙河子期盆地伸展方向发生旋转,最终营城期伸展方向为近E-W向,并在长岭地区形成了统一的NE向延伸的沉降带。伴随伸展方向的转变,盆地内部的构造样式在不同时期也存在着变化,显示存在不同的应变模式。基于地震剖面的构造样式分析显示在形成断陷盆地的过程中存在两种应变模式。初期主要发育地堑、地垒式构造样式,为纯剪切应变的产物。随后转为叠瓦状的半地堑构造样式(变质核杂岩构造),为简单剪切应变产物。后期构造叠加在前期构造之上造成了长岭地区复杂的构造样式。研究发现,在盆地的伸展过程中地壳或岩石圈的厚度与应变模式之间存在相关性。在岩石圈厚度较大的高原背景下,地壳的伸展变形以发育地堑、地垒式构造样式为代表的纯剪切应变(对称伸展)为特征;变质核杂岩式构造所代表的简单剪切应变(不对称伸展)形成于较薄的岩石圈背景下。两种应变机制不仅存在于岩石圈伸展的不同构造层内,也存在于伸展过程中的不同阶段。更多还原

【Abstract】 Guiding by the rules of the global plate tectonics mobilism and the basic theory of spatial and temporal/episodic development of regional geology, using the new concepts and methods of the Modern Tectonic Geology as well as the Basin Analysis, this paper discussed the geometric, kinematical and geodynamical characters of the Changling Area’s faulted depressions in the southern Songliao rift by the comprehensive research basing on the geological field investigation, volcanic features, seismic profiles, drilling and logging data Basing on those studies, it described the structural evolution of the fault depressions in Changling Area during the early Cretaceous and discovered the differentiation of the strain pattern during the crustal extension in the southern Songliao Basin.The stratigraphies of Changling Sag Basin from Cretaceous to Quaternary could be divided into three Tectono-stratigraphic units. The lower unit filled into the faulted depression can be also divided into four groups, such as: Huoshiling Group, Shahezi Group, Yingcheng Group as well as Denglouku Group from the bottom to the top, which represent the different stage’s sediments of early Cretaceous. The surface between the fault basin and depression basin is defined in the middle of Denglouku Group. The types of sediment facies, such as fan delta sediment, braided delta sediment, alluvial fan sediment, fluvial plain sediment of braided river as well as lacustrine sediment, organized together and reflected the control of the margin of syn-normal fault and the broken-slope to sediment facies.The syn-sedimentary faulting cut into the basement have two mainly directions-the NE and the SW- which controlled the formation of the fault basin. The analysis of the balanced section based on the seismic profiles across the fault basin along NE direction and SW direction indicates that the extension which formed the fault basin turned from NE to nearly E-W along the clock direction during the stages mentioned above. At the beginning, Huoshiling stage, the direction of extension is along NE, and the center of subsidence composed three belts and distributed mostly along the NW at Changling fault depression and Qianan fault depression. Following that, the extension direction turned during the Shahezi stage. Finally, the mainly extension direction is nearly along the E-W during the Shahezi stage and Yingcheng stage. It formed a union subsidence belt along NE direction at the three fault depressions. This process can also be find at Shiwu fault depression-a half-graben formed at the same time southeast to Changling area.Accompanied by the change of extension direction, the structure patterns also changed at different stages during the forming of the fault basin. The analysis of structure pattern basing on the seismic section show there are two kinds of strain pattern forming the fault basin at Changling area. At the first stage, the main structure pattern was graben and horst which usually represented the strain pattern of pure-shear deformation. After that, it changed into imbricate half graben which formed usually under the Sample shear conditions. The second type overlaid on the first and made the structure of Changling area complex.The studies show that there are some relationship between the thickness of crust or lithosphere and the strain pattern during the extensional process. The Pure-shear Model presented by the way of graben or horst-a symmetry extension-was formed on the plateau background with thicker lithosphere and the Simple-shear Model presented by the form of metamorphic core complexes model-a dissymmetry extension- was usually formed on the thinner lithosphere. Both of the two deformation models are not only exist in the different layer of lithosphere, but also exist in different stage during the extension process.更多还原