分支河流体系河道弯度沿程变化规律——以格尔木河流扇为例  

Downstream River Channel Sinuosity Variation of the Distributive Fluvial System:A case study from the Golmud fluvial fan

作　　者：孙家惠 张昌民[1] 王浩楠 张祥辉 冯文杰[1] SUN JiaHui;ZHANG ChangMin;WANG HaoNan;ZHANG XiangHui;FENG WenJie(School of Geosciences,Yangtze University,Wuhan 430100,China)

机构地区：[1]长江大学地球科学学院,武汉430100

出　　处：《沉积学报》2024年第3期981-993,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42130813)。

摘　　要：【目的】研究分支河流体系河型演变规律,建立相应参数的数据库,可为盆地范围内的沉积体系分布预测提供数据基础。【方法】利用Google Earth、Global Mapper地理信息软件,按照等比例网格进行河道弯度指数的采集,分析弯度指数沿程变化规律,建立格尔木河流扇河型演变的沉积模式。【结果】共测量河道弯度指数2 989个,根据格尔木河流扇河道弯度指数特征,可将格尔木河流扇划分为辫状河段、辫曲共生段、大型高弯曲流河段、小型低弯曲流河段4个部分:(1)辫状河段坡度0.70%,发育低弯度顺直河和辫状河,辫流带宽度大,河道弯度指数1.01~1.43,平均弯度指数1.08,主要发育辫状河道、废弃河道、泛滥平原等微相;(2)辫曲共生段坡度0.63%,既发育辫状河也发育曲流河,不同位置辫状河和曲流河发育程度和河道弯度指数大小不同,河道弯度指数1.08~5.00,平均弯度指数1.52,主要发育辫状河道、曲流河道、废弃河道、决口扇、沙丘、泛滥平原等微相;(3)大型高弯曲流河段坡度0.29%,以大型曲流河为主,河道宽,河湾摆幅大,河道弯度指数1.12~5.00,平均弯度指数1.83,主要发育曲流河道、废弃河道、沙丘、泛滥平原等微相;(4)小型低弯曲流河段坡度0.08%,主要发育小型分叉状的曲流河,河道窄,河湾摆幅小,河道弯度指数1.07~3.13,平均弯度指数1.51,主要发育曲流河道、废弃河道、决口扇、沙丘、泛滥平原等微相。【结论】建立了格尔木河流扇河型演变的沉积模式,为开展地下沉积体系分布预测提供新的基础数据。[Objective]We aimed to study the evolution of river patterns in the distributive fluvial system,establish a database of corresponding parameters,and provide a data basis for predicting the distribution of sedimentary systems within the forecast basin.[Methods]Using modern geographic information software such as Google Earth and Global Mapper,the channel sinuosity was measured based on a grid of equal proportions,analyzing the variation of the channel sinuosity along the course and establishing the depositional mode of the evolution of the Golmud fluvial fan[.Results]A total of 2989 channel sinuosity data were measured,and based on the characteristics of the sinuosity of the Golmud fluvial fan,the Golmud fluvial fan can be divided into four sections:"braided river,""braidedmeander coexistence,""large high-sinuosity meandering river,"and"small low-sinuosity meandering river section":(1)The slope of the braided river section was 0.70%,developing both the straight and braided river with low sinuosity.The braided belt width was large.The channel sinuosity was 1.01-1.43,the average sinuosity was 1.08,and microfacies such as braided river,abandoned river,and flood plain were developed;(2)The slope of the braidedmeander coexistence section was 0.63%,developing both braided and meandering river,and the development degree and river sinuosity varied in different positions.The channel sinuosity was 1.08-5.00,and the average sinuosity was 1.52;microfacies such as braided river,meandering river,abandoned river,crevasse splay,sand dunes,and flood plain were developed;(3)The slope of the large high-sinuosity meandering river section was 0.29%,mainly developing a large meandering river.The channel was wide,the river bend swing was large,the channel sinuosity was 1.12-5.00,and the average sinuosity was 1.83;microfacies such as meandering river,abandoned river,sand dunes,and flood plain were developed;(4)The slope of the small low-sinuosity meandering river section was 0.08%,mainly developing a small bifurcated meandering river,nar

关 键 词：分支河流体系 河道弯度指数 河型 河型演变 格尔木河流扇 

分 类 号：P512.2[天文地球—地质学]