转换型陆缘——尼日尔三角洲盆地成因类型再认识  

A transform margin: Review of genetic types of the Niger Delta Basin

作　　者：冯志强[1] 郭丰涛 张忠民 殷进垠[1] 田纳新 苏玉山[1] 郭荣涛 吴高奎 FENG ZhiQiang;GUO FengTao;ZHANG ZhongMin;YIN JinYin;TIAN NaXin;SU YuShan;GUO RongTao;WU GaoKui(Research Institute of Petroleum Exploration&Production,SINOPEC,Beijing 102206,China)

机构地区：[1]中国石油化工股份有限公司勘探开发研究院,北京102206

出　　处：《岩石学报》2022年第9期2565-2580,共16页Acta Petrologica Sinica

基　　金：国家重大专项(2016ZX05033);中石化科研项目(P21043-3、P20057-3、P22085、P22086)联合资助.

摘　　要：尼日尔三角洲盆地是世界上规模最大、油气最为富集的陆缘三角洲盆地之一,过去普遍被认为是起源于白垩纪三叉裂谷的伸展型被动大陆边缘盆地。本文综合前人研究,剖析贝努埃槽和非洲陆上断裂体系及其相关盆地构造-地层结构,认为冈瓦纳大陆裂解前(侏罗纪-早白垩世)陆内存在巨型走滑断裂系,先期裂开的南大西洋和中大西洋沿该断裂系贯通形成赤道大西洋;提出了尼日尔三角洲盆地为受先存大型走滑断裂体系影响的转换型陆缘盆地,具有明显的窄洋陆过渡带特征,致使现今三角洲主体沉积于新生洋壳之上;重建了尼日尔三角洲盆地裂陷期、过渡期和陆缘期的形成演化历程,提出因边缘脊和洋底转换脊的遮挡作用,在过渡期转换型陆缘更有利于形成局限的海洋环境,为形成大面积优质烃源岩创造了良好条件,大幅度地提升了转换型陆缘盆地的油气勘探前景。The Niger Delta Basin is one of the largest petroliferous continental margin basins in the world.It is generally considered to be an extensional passive continental margin basin originated from the Cretaceous Trigeminal Rift.Based on the analyses of the tectonic-stratigraphic structure of the Benue Trough and the fault systems and its related basins in the West and Central Africa continents,it is believed that there was a giant strike-slip fault system across the combined continents of South America and Africa before the breaking-up of Gondwana(Jurassic to Cretaceous),and the South Atlantic Ocean and the Central Atlantic Ocean,which were opened earlier,were connected along the fault system to form the Equatorial Atlantic Ocean.It is proposed that the Niger Delta Basin is a transform continental margin basin affected by the preexisting large strike-slip fault system,and has obvious characteristics of a narrow ocean-continent transition zone,which explains why more than 2/3 of the Niger Delta lays on oceanic crust.It is also proposed that a transform continental margin basin should have much greater potential for oil and gas accumulations than people originally thought,because of the zigzagged margin shape,the marginal ridges,the marginal plateau and the ocean floor transition ridges which constrain the marine flows to create favorable conditions for forming large area of high-quality source rocks during the transition stage between the rifting stage and the fully open continental margin stage.

关 键 词：尼日尔三角洲盆地 贝努埃槽 伸展型陆缘 转换型陆缘 被动陆缘 盆地成因 

分 类 号：P542.3[天文地球—构造地质学] P618.13[天文地球—地质学]