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海拉尔盆地是叠置于内蒙-大兴安岭古生代碰撞造山带之上的中-新生代盆地,总体上呈北东向展布,由三坳、两隆5个一级构造单元组成,自西向东依次为扎贲诺尔坳陷、嵯岗隆起、贝尔湖坳陷、巴彦山隆起和呼和湖坳陷,其中红旗凹陷是位于贝尔湖坳陷北部的一个二级构造单元。研究表明,红旗凹陷在早白垩世经历了4个变形阶段:在早白垩世兴安岭群-南屯组沉积时期为NW-SE向伸展作用阶段,形成以大型犁式正断层为控陷断层的NE向箕状半地堑;在大磨拐河组-伊敏组一段沉积时期为NW-SE向挤压作用阶段,使早期控陷正断层发生强烈的反转作用而转化为逆断层,靠近控陷断层的NW边界由于断层上盘的逆冲而隆升,凹陷的SE斜坡带由于控陷断层在反转作用过程中深部的逆冲滑移在浅部受阻而发生的旋转式隆升,使凹陷的规模发生明显萎缩,并在凹陷的中部形成大型NE向断层转折褶皱,构成了红旗凹陷的中部断隆带;在伊敏组二段下部沉积时期为近EW向伸展作用阶段,早期控陷断层表现出正断层的特征,新形成的NE向控陷断层具有左行离散型走滑的性质;在伊敏组二段上部沉积时期为近EW向挤压作用阶段,早期控陷断层再次表现为上盘逆冲的特征,在断层上盘、靠近断层的部位形成反转背斜,并在凹陷中形成断层转折褶皱。在每一变形阶段中,红旗凹陷的构造特征在空间上存在一定的差异。
The Hailar Basin is a Meso-Cenozoic basin superimposed on the Paleozoic collision orogenic belt in Inner Mongolia-Daxinganling. The basin is generally distributed in the northeast direction and consists of five primary tectonic units of the three Au and the two lonelocks. From west to east, they are Zhanbenuoer depression, Konggang uplift, Bell Lake depression, Bayan mountain uplift and the Hohhu depression, in which the Hongqi Sag is a secondary structural unit located in the northern part of the Belle Depression. The study shows that the Hongqi Sag experienced four deformation stages during the Early Cretaceous. During the Early Cretaceous, the NW-SE direction was extended during the deposition of the Xing’anling Group-Nantun Formation, and a large-scale plow-type faulted fault was formed NE to the half graben; In the NW-SE direction during the deposition of the first member of the Damoguaihe-Yimin Formation, the normal faults in the earlier controlled traps were reversed strongly and turned into reverse faults, The NW boundary of the controlled fault rises due to the thrusting of the upper plate of the fault. The SE slope zone of the depression shows a rotational uplift due to the blockage of the deep thrust during the reversal of the fault, The size of the depression was obviously atrophied, and large NE-trending fault fold folds formed in the middle of the depression, which formed the middle fault belt of the Hongqi Sag. During the depositional period of the lower part of the second member of the Yimin Group, The subsidence layer shows the features of normal faults. The newly formed NE-trending fault has the characteristics of left-lateral discrete strike-slip. In the upper sedimentary period of the second member of Yimin Formation, The performance of the plate thrust characteristics, in the fault The plate, near the fault site, forms an anticlockwise anticline and forms fault fold folds in the depression. In each stage of deformation, there are some spatial differences in the structural features of the Hongqi Depression.