南堡凹陷北端古近系地层构造解析——断层链接处“变换生长”现象及其意义  

Structure analysis of the Paleogene strata in the northern Nanpu sag:The “transfer growth” phenomenon in fault links and its significance

作　　者：刘晓文[1] 常迪[2] 施尚明[1] 何春波[1] 魏华彬[1] LIU Xiaowen;CHANG Di;SHI Shangming;HE Chunbo;WEI Huabin(College of Geosciences,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Natural Gas Exploration Company,Qinghai Oilfield,Geermu,Qinghai 816000,China)

机构地区：[1]东北石油大学地球科学学院,黑龙江大庆163318 [2]青海油田天然气开发公司,青海格尔木816000

出　　处：《中国矿业大学学报》2018年第6期1287-1294,共8页Journal of China University of Mining & Technology

基　　金：国家青年科学基金项目(41702153);东北石油大学研究生创新科研项目(YJSCX2015-001NEPU)

摘　　要：选择构造位置最为典型的南堡凹陷北端作为研究区,利用三维地震资料精细解释成果,针对不同时期开展了活动断裂分析、沉降中心位置分析等工作.明确了研究区沙三期主控断层活动强度最大位置走向与次级活动断层主要走向均为北东向,至沙一期转变为近东西向.通过观察主控断层的三维空间形态,提出西南庄断层和柏各庄断层链接处存在"变换生长"现象,表现为断层深部连续、至浅部分开,且走向发生改变.同时指出与先存断层走向相差近45°方向的伸展应力条件是产生该现象的原因,揭示了该区域应力体制转换后的性质为南北向伸展而非走滑.研究结果表明:研究区在沙三期的应力体制为强烈的北西-南东向伸展;沙二时期为应力体制过渡时的平静期(剥蚀期);从沙一期开始应力体制变为强烈的南北向伸展,并派生出走滑分量;东营期后强度减弱.南堡凹陷与研究区应力体制一致.The north of Nanpu sag,the most typical area in tectonic position,was chosen as the research area.Based on the detailed interpretation of 3 Dseismic data,the activity faults and the settlement center position in different periods were analyzed.It is clear that the trend of the most active part on the major faults and the main trend of secondarily active faults were both NE during E_2s^3 period of the research area,and transformed to nearly EW at E2 s1 period.By observing the three-dimensional shape of the main control faults,the phenomenon of＂transfer growth＂in the Xi＇nanzhuang and Baigezhuang fault links was found,which is characterized by a continuous fault in the depth,and separation into two sections in the shallow with a changing trend.Meanwhile,it is pointed out that the extension stress at the direction of nearly 45°awayfrom the pre-existing fault trend is the cause of the phenomenon,which reveals that the nature of the regional stress regime was a NS extension rather than a strike-slip.The results confirmed that the stress system of E_2s^3 period in the study area was a strong NW-SE orientated extension.E2 s2 period was a calm period（also a period of erosion）when the stress system transformed.At the beginning of E2 s1 period,the stress system transformed into a strong SN extension,and derived a strike-slip correspondingly.After Dongying period,the stress intensity was weakened.The stress system of Nanpu sage is consistent with the study area.

关 键 词：南堡凹陷 柏各庄断层 西南庄断层 构造解析 伸展构造 断层“变换生长”现象 

分 类 号：P548[天文地球—构造地质学]