鄂西地区南沱组地层沉积特征及成因分析

以沉积学，流体力学的基本原理为基础，运用沉积对比，粒度统计等方面对鄂西地区南沱组杂砾岩的成因机理进行了探讨，通过岩石类型，剖面层序，岩石的砾石表面特征、碎屑颗粒分布规律及沉积物构造研究后认为，南沱组杂砾岩并非冰碛砾岩，而属海缘盆地下水泥石流和浅海相沉积。

RESEARCH ANALYSIS FOR THE CHARACTER AND GENESIS OF NANTUO FORMATION DIAMICTITE IN THE WESTERN AREA OF HUBEI, CHINA

It has been regarded as the glacial sediment that Nantuo Formation is a important Sinianindicator horizon in the southern Chnai for a long time. But, Its lithological features and formation attitude indicated that it is a multfacies lithosmic body, which is composed of the terrigenous alluvial fan, normal shallow marine and volcanic sediments. Nantuo diamictitic wacke were formed by interrupting block glacier early. The rubble flow can be divided into thin and bonding flows acccording as it is fluvical shape properties and condition of transportation matrix. The former is composed of better layering, difference obviously and lower chasorrite basis. It is usually located in the middle and upper of alluvial fan, but the latter is not. The debris flow sendimentary was come of the location of ing terrigenous denudation, deposit in marginal shallow marine or faulting basin. It is covered by normal shallow marine sediments during the debris flow interrupting. The sediments contain volcanic composition. The composition of Nantuo Formation is very complex, but the regional difference is very obvious. It is a exemplary proximal deposit. The origin of sediment and shape, and scale is under the control of palaeogeographic condition Nantuo Formation is in the form of a prone in the study area. Thickness and lithic factes is a larger transformation. Palaetectonic maying and volcanism are the power of debris flow.