Sedimentary characteristics of distributive fluvial system in arid area: A case study of the Shule River distributive fluvial system, NW China  

作　　者：ZHANG Xianghui ZHANG Changmin FENG Wenjie XU Qinghai ZHU Rui LIU Shuai HUANG Ruoxin 

机构地区：[1]School of Geosciences,Yangtze University,Wuhan 430100,China

出　　处：《Petroleum Exploration and Development》2021年第4期877-888,共12页石油勘探与开发（英文版）

基　　金：Supported by the National Natural Science Foundation of China(41772094);National Science and Technology Major Project(2016ZX05027-002-007)。

摘　　要：Based on detailed investigation of the modern sedimentation of the distributive fluvial system of Shule River and the data of unmanned aerial vehicle(UAV)aerial photography and satellite remote sensing,the sedimentary characteristics and differences of distributive fluvial system in arid areas are analyzed.By comparing the changes in slope,river morphology and sedimentary characteristics in different sections from the apex to the toe,the distributive fluvial system of Shule River can be divided into three facies belts:"proximal","middle"and"distal".The proximal belt has the largest slope and strongest hydrodynamic condition,mainly appears as large-scale braided river deposits;the fluvial bars in this belt are mainly composed of gravels,the gravels have good roundness and certain directionality,and are medium-large boulders,with low sand content;the main microfacies in this belt are braided channel and flood plain.The middle belt with slope smaller than the proximal belt,is mainly composed of braided bifurcating river deposits.Due to branching and infiltration,this belt has weaker hydrodynamic conditions,so some of the distributive rivers dry up,appearing as ephemeral rivers.This belt has small lenticular sandbodies,fine to medium gravels,higher sand content,and mainly braided channel,flood plain and aeolian dune microfacies.The distal belt has the smallest slope and flat terrain,where the river begins to transform from braided river to meandering river,the sediment is mainly sand.Due to the influence of slope,this belt has weaker erosion toward source and stronger lateral erosion,and point bars developing around the edge of the active lobes.In this belt,the river is completely meandering,and the main microfacies are braided channel,meandering channel,flood plain,aeolian dune,lake and swamp.

关 键 词：Shule River distributive fluvial system river morphology sandbody distribution sedimentary characteristic sedimentary structure 

分 类 号：P618.13[天文地球—矿床学]