摘要
河流在洪水期携带大量陆源碎屑,当其入湖或入海后,由于洪水密度大于周围水体的密度,洪水发生下沉并沿盆地底部长距离运移,形成陆源下潜流或异重流。异重流形成的相关沉积岩被统称为异重岩。异重岩通常由一个底部的反粒序单元和一个顶部的正粒序单元组成,反粒序单元反映了异重流能量的逐渐增强,正粒序反映了流体能量的逐渐减弱。异重流以3种方式搬运碎屑颗粒,即底载搬运、悬浮搬运和漂浮搬运。根据搬运方式的不同,异重岩分为3类岩相,即底载成因的B类岩相、悬载成因的S类岩相和漂浮物成因的L类岩相。异重流的沉积充填形成了河道、堤岸和朵叶体3类微相,内部岩相变化极为发育。异重岩的沉积特征虽然典型且较易识别,但是常被误认为是砂质碎屑流、滨岸相、三角洲相或河流相沉积。
Flooding river discharges a sediment-water mixture having a bulk density that often exceeds that of the water in the receiving water body. Consequently, when these flows enter a marine or lacustrine basin they plunge and move basinward as a land-derived underflow or hyperpycnal flow. Deposits related to hyperpycnal flows are hyperpycnites. Some fine hyperpycnites are composed of an inversely graded （waxing flow） basal unit, followed in transition by a normally graded （waning flow） unit.Three main facies families related to the three main elements that govern the movement of almost all sustained hyperpycnal discharges in marine settings： bedload, suspended load and lofting. These facies categories are here termed as B （bedload related sedimentaryfacies） , S （suspended-load related sedimentary facies） and L （lofting related sedimentary facies）. Hyperpyc- nites include three kinds of depositional elements： channel fill, lobes and levee deposits. Although hyperpycnites display typical and diagnostic characteristics that allow a clear recognition, these deposits are often misinterpreted in the literature as sandy debrites, shoreface, estuarine of fluvial deposits.
出处
《岩性油气藏》
CSCD
北大核心
2018年第1期1-18,共18页
Lithologic Reservoirs
关键词
异重流
异重岩
浊流
深水沉积
内乌肯盆地
鄂尔多斯盆地
松辽盆地
西伯利亚盆地
hyperpycnal flows
hyperpycnites
turbulent flow
deep water sedimentary
Neuqudn Basin
OrdosBasin
Songliao Basin
Siberian Basin
