转换型边缘盆地转换边缘类型识别与特征分析: 以非洲科特迪瓦盆地为例  

Recognition and characteristic analysis of the transition boundary for transform marginal basin:A case of Cote d′Ivoire Basin,Africa

作　　者：盖海洋 姜烨 张科 王伟 Gai Haiyang;Jiang Ye;Zhang Ke;Wang Wei(CNOOC International Ltd.,Beijing 100028,China)

机构地区：[1]中国海洋石油国际有限公司,北京100028

出　　处：《地质科技通报》2021年第5期83-90,共8页Bulletin of Geological Science and Technology

基　　金：国家科技重大专项“非洲重点区油气勘探潜力综合评价”(2017ZX05032-002)。

摘　　要：转换型边缘盆地是一类特殊的大陆边缘盆地,前人对其研究较少,随着近十几年在转换型边缘盆地的一系列重大油气发现,该类型盆地越来越受到重视。但在盆地边缘转换断层的识别解释、转换断层对盆地构造格局的影响以及转换断层相关的火山活动对盆地的影响方面等研究仍相对较少。以典型的转换型边缘盆地——科特迪瓦盆地为研究对象,从盆地的转换边缘入手,利用多种数据综合分析,识别出转换型边缘盆地的两类转换边缘——转换型边缘和过渡离散型边缘,并分别总结了其各自特征;对比了两类转换型边缘在地层发育、断裂体系、火山活动以及应力场等方面存在的差异及其对盆地造成的影响。研究结果表明,典型的转换型边缘盆地具有转换型边缘和过渡离散型边缘两种不同类型的洋陆过渡边缘;两类边缘在接触关系、火山活动强度、对早期地层的改造作用等方面具有显著差异;转换型边缘盆地结构受早期断裂和转换断裂的双重控制,受多期构造运动改造,拉张与走滑应力叠加,使早期断裂具有走滑和拉张双重性质,多期的改造作用对油气运聚及保存具有显著影响。转换断层附近早期断裂可能会发生反转作用,断裂性质发生改变,形成挤压构造或地层反转。This paper takes the typical transform passive marginal basin,eg.Cote d′Ivoire Basin as the research object,starting from the transitional edge of the basin,by using comprehensive analysis of various data.We identified two types of transform margins in the marginal basin and summarized respective characteristics;we also compared the differences between two types of transform margins in stratigraphic development,fault systems,volcanic activity,stress fields and different impact on the basin.Through the research of this article,it is believed that a typical transform continental margin basin has two different types of ocean-continent transform margins:transitional margins and transitional discrete margins;There are significant differences between the two types of margins in terms of contact relationship,volcanic activity intensity,and transformation of early strata;The transform continental margin basin structure is controlled by both early faults and transitional faults system.Especially at the transform discrete margins,tensile and strike-slip stresses are overlapped.After multi-stages of structural transformation,the early fault system has dual properties of strike-slip and tension,and multi-stages structural transformation also has a significant impact on oil and gas migration,accumulation and preservation.Early faults near the conversion faults may undergo reversal effect,and the nature of the early faults may change,resulting in compression structures or stratigraphic reversals.

关 键 词：转换型边缘盆地 转换边缘 火山活动 走滑作用 

分 类 号：P618.130.2[天文地球—矿床学]