龙川江盆地上第三系芒棒组沉积体系与层序地层分析  

Analysis on sequence stratigraphy and depositional systems of Mangbang Formation,Upper Tertiary in Longchuanjiang basin

作　　者：孙泽轩 姚毅锋 陈勇 李国新 

机构地区：[1]核工业280研究所,四川广汉618300

出　　处：《铀矿地质》2004年第5期286-293,298,共9页Uranium Geology

摘　　要：龙川江盆地是造山带内部发育的新生代小型山间断陷盆地。本文结合该盆地晚新世构造、火山活动与沉积作用 ,对盆地盖层芒棒组沉积体系与层序地层进行了分析。通过分析 ,建立了龙川江盆地晚新世沉积模式 ,认为晚新世早期断陷带内快速堆积 ,主要以发育冲积扇沉积体系为特征 ,中、晚期冲积扇快速入湖 ,由此而形成冲积扇 扇三角洲 湖泊沉积体系组合 ;提出了龙川江盆地芒棒组层序的形成受多期构造活动控制的观点 ,并建立了 3个构造层序 。Longchuanjiang basin is a small Cenozoic intramontane down-faulted basin.This paper,combining the Pliocene structure,the volcanic activities and the sedimentation of the basin,analyses the sequence stratigraphy and the depositional systems of Mangbang formation(the cover of the basin).Based on the analysis of depositional systems of Mangbang formation,the depositional pattern of Pliocene in Longchuanjiang basin is set up.It is suggested that because of the fast accumulation in early down-faulted zone during Pliocene time,the alluvial fan depositional system was dominated at that time.During the middle-late period,the allavial fan entered the lake forming a combination of fan-fandelta-lacustrine depositional systems.Authors propose a view point that the formation of Mangbang formation sequence was constrained by multistage tectonic movement,and three structural sequences were established,and system tracts were divided.

关 键 词：沉积体系 构造层序 体系域 芒棒组 龙川江盆地 

分 类 号：P539.2[天文地球—古生物学与地层学]