泥石流沉积相模式  

A FACIES MODEL OF DEBRIS FLOW

作　　者：崔之久[1] 熊黑钢[1] 

机构地区：[1]北京大学地理系

出　　处：《沉积学报》1990年第3期128-140,共13页Acta Sedimentologica Sinica

基　　金：自然科学基金

摘　　要：共划分泥石流沉积为6种类型或相即A相泥石流层,B相类泥层,C相冲刷层,D相泥流层;E相泥流层,A1相细粒泥石流层。标准的泥石流相模式是从底层的泥层D相开始,往上为A相、C霜。且以C相为沉积间断标志。Based on observation and statistical analysis of the textural, structural, grainsize and stratigraphic relationship data of ten profiles, we found six types of debris flow facies: Facies A (Coarser) Debris flow layer, which is the main body of debris flow, has a gravel content 25 percent to 50 percent and suspensio and support framwork. Facies B surface mud layer, which is formed by fane sediment floating up to the surface at flat area after the debris flow stopped, is the contemporaneous out-facies of the erosional layer (Facies B) and not be erosioned. The deposit consists of coarser sediment and has dry polygonal ground sometimes. Facies C Erosional layer, which is formed by fluvial erosion reforming on the surace after the debris flow deposited, The deposit appears loosely and porously, and deposit break hiatus. Facies D Basal mudh layer, which is formed by sedimentary bed paving processes in the earlier stage flood before debrcs flow appears. Facies E Mud layer, which is the main deposit body of mud flow in leoss area. By means of statistical analysis, nine local facies models had been found that can satisfy the statistical equire. The facies C.D.A. and B are the most common layers appear in deposit. A complete debris flow succession consists of facies D, A and B layer. The facies C layer is formed by later fluvial erosion and sometimes replaces the facies B. Therefore, a typical facies model of debris flow consists of C, D, A and B layer. The above mentioned models show some difference at different landforms. For example, at the top of debris flow fan, the deposition is strong and the later stage erosion is strong also, therefore, facies A and facies C develope, but on facies B and D. In this situation, facies succession is AC-AC type. At middle and base of a fan, the deposit shows typical facies model, with a well developed facies A, an obvious facies D and a less developed facies C. The facies B sometimes developes at both sides of debris flow

关 键 词：泥石流 相模式 沉积结构 沉积构造 

分 类 号：P588.2[天文地球—岩石学]