逆冲断层位移—长度关系解析——以杭锦旗断裂带为例  

Analysis of displacement—length relationship of reverse faults:a case study of Hangjinqi fault zone

作　　者：李书林 李良[2] 贾会冲[2] 张威[2] 徐恒艺 杨明慧[1,3] LI Shulin;LI Liang;JIA Huichong;ZHANG Wei;XU Hengyi;YANG Minghui(College of Geosciences, China University of Petroleum, Beijing, 102249;North China Company, SINOPEC, Zhengzhou, 450006;State Key Laboratory of Prtroleum Resources and Prospecting, China University of Petroleum, Beijing, 102249)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石化华北油气分公司勘探开发研究院,郑州450006 [3]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《地质论评》2019年第2期289-300,共12页Geological Review

基　　金：国家自然科学基金资助项目(编号:41172127;41572102)的成果~~

摘　　要：为了揭示鄂尔多斯盆地北部杭锦旗断裂带在晚石炭世—中三叠世逆冲断层生长的位移模式和位移—长度关系,本文通过地震剖面解释、地层回剥分析和断层古位移测算来厘定古断层的末端位置,明确断裂生长连接历史,并结合幂律关系,探究了断层生长模式以及断裂带岩性组合、运动学、反转和断层系统内在特征等方面的影响。研究表明,杭锦旗断裂带的构造演化受基底断裂的分段性制约。其北东走向的分段(泊尔江海子断裂东段)形成较早;在垂向上,断裂中部的位移大,向两端递减;在平面上,断裂末端与东西走向的分段(泊尔江海子断裂西段)叠覆,导致局部位移增大,最终发生硬连接。东西走向的三眼井断裂形成于晚石炭世,先后经历了断层分段、横向扩展和连接的演化阶段。乌兰吉林庙断裂作为调节带断裂,其活动相对较弱且局部发生反转。根据断层位移—长度剖面的几何形态和断层演化阶段分析,可将杭锦旗断裂带的逆冲阶段的位移模式分为4种类型:①近对称的三角状或椭圆状,代表独立断层;②左右极不对称的锯齿状或双峰状,代表断层之间发生软连接作用;③不规则波状,反映多条小型断层的连接作用;④异常尖峰状,代表大型断裂后期位移的调整。杭锦旗断裂带的D_(max)/L数据集与全球其他地区比较,要低一个数量级,可能与断裂带的后期反转有关。最后,针对杭锦旗断裂带在不同时期的构造演化和D_(max)/L变化特征,提出了断裂带逆冲阶段演化的路径模式。Objectives: Based on the investigation of the formation and evolution of the Hangjinqi fault zone in the northern Ordos Basin,this paper discusses the displacement evolution characteristics and influencing factors of the fault zone from the Late Carboniferous to the Middle Triassic through the fault displacement-length relationship study.Methods: Through a series of seismic section interpretations,throw and dip angles of these faults are measured. Through the stratum recovery analysis,the displacement along the faults in different periods and the location of the ancient fault tips are approximately calculated,the history of fault growth connections is determined,and the displacement-length relationships in the evolution of the reverse faults is analyzed.Results: The evolution of the Hangjinqi fault zone is controlled by the basement faults. Among them,the NEtrending fault zone evolved earlier,mainly in the form of displacement growth. The soft linkage between the fault tip and the overlying fault zone resulted in an increase of local displacement and eventually a hard linkage. the EWtrending fault zone developed in the later stage. The fault segmentation,lateral propagation,and connection process are involved;the fracture activity in the central adjustment zone is relatively weak and locally reversed.Conclusion: We find that the evolution zoning characteristics of the Hangjinqi fault zone from the Late Carboniferous to the Middle Triassic include: the east-west basement fault zone,the northeast basement fault zone,and the intermediate adjustment zone. Based on the geometry of the fault displacement-length profile and the analysis of the fault evolution stage,four types of reverse fault displacement patterns can be simply classified:(1) Nearly symmetric triangles and ellipses,representing a single fault;(2) The left-right asymmetric zigzag or double peaks,representing soft linkage between faults;(3) Irregular wavy,reflecting the connection of multiple faults;(4) Abnormal peaks,representing late displacement adjust

关 键 词：逆冲断层 古断距 断层生长连接 位移-长度关系 位移模式 杭锦旗断裂带 鄂尔多斯盆地 

分 类 号：P618.13[天文地球—矿床学]