Downstream River Channel Sinuosity Variation of the Distributive Fluvial System:A case study from the Golmud fluvial fan
[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 sys-tems 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 2 989 channel sinuosity data were measured,and based on the characteristics of the sinuosi-ty of the Golmud fluvial fan,the Golmud fluvial fan can be divided into four sections:"braided river,""braided-meander 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 braided-meander 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 develop-ing 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,narrow channel,and small river bend swing;the channel sinuosity was 1.07-3.13,with an average sinuosity of 1.51,and microfacies such as meandering river,abandoned river,crevasse splay,sand dunes,and flood plain were developed.[Conclusions]The depositional model of river-type evolution of the Golmud fluvial fan was established,which provided a new knowledge base for the prediction of the distribution of underground sedimentary systems.
distributive fluvial systemchannel sinuosityriver patternsriver evolutionGolmud fluvial fan
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