【摘要】 本文根据测井曲线及地震相特征,建立了深水层序界面划分的5种判别标准,将尼日尔三角洲盆地深水区中中新统—上中新统地层划分了6个三级层序,2个二级层序。根据深水沉积自身沉积旋回所具有的二元结构特征及三角洲与陆架区相对海平面变化之间的关系,将经典的三分体系域划分为二分体系域:异地沉积体系域和原地沉积体系域。其中,异地沉积体系域从基准面下降开始—海侵早期,主要发育重力流沉积(块状搬运沉积、浊积扇);原地沉积体系域从海侵中、晚期—基准面上升最大位置结束,主要以原地沉降的泥质披覆沉积为主。本文分析了层序发育的影响因素,综合研究认为:气候条件、海平面变化、构造抬升、沉积物供给、大陆架宽窄等共同制约了研究区深水沉积层序的发育。更多还原

【Abstract】 Based on bore logs and seismic facies characters,the article establishes five criteria for judging sequence boundary of deep-water setting.The strata of middle-upper Miocene in the Nigeria deep-water setting areas were divided into six third-order sequences,two second-order sequences.According to two-component constitution feature of deep-water depositional cycle,the relation between the deltas and the relative sea-level change in shelf area,this study modified classic threefold division of system tracts into twofold division of system tracts:allogenetic system tract and autogenetic system tract.Allogenetic system tract starts from base level descending to early stage of transgression,and it mainly has gravity current deposits that are composed of mass transport deposits and turbidite fans.Autogenetic systems tract starts from middle-late stage of transgression to base level rising to the highest position,and it mainly deposits pelagic and hemipelagic argillaceous sediments.This study also analyzed controlling factors of sequence stratigraphy development.Comprehensive study shows that many factors such weather condition,seal level change,tectonic lifting,sediments supply,and width of continental shelf jointly determine sequence development of deep-water deposit sequences.更多还原