Surface Processes Indicated by Grain Size of Holocene Palaeoflood Sedimentary Sequences in the Ruhe,a Tributary of the Huaihe River
[Objective and Methods]For a profound understanding of the evolution of the Holocene environment and surface processes in the Huaihe River Basin.Through a detailed field investigation in the Huaihe River Basin,a Holocene loess soil stratigraphic profile with multiple layers of paleo-flood stagnant sediments was found at the front of the first-level river terrace in the Zhushixiang section of the upper reaches of the Ruhe River.The section was observed and measured in detail,stratigraphic division and stratified sampling were conducted,and various index analysis and research are performed in the laboratory.In this study,based on the previous study of sedimentological properties and dating,the end member(EM)analysis method was used to analyze the grain size components and further reveal the provenance of this palaeoflood sediment sequence and the change law of its sedimentary dynamic characteristics.[Results]From this sedimentary sequence,four EM components with different provenance and sedi-mentary significance were analyzed by the nonparametric method.With the exception of the modern flood sediment and fine sand layers of the floodplain facies,the other layers in each stratigraphic soil unit exhibited characteristics of mixing and superposition of multi-EM components.[Conclusions]Combined with the comprehensive analysis of the macroscopic characteristics and physical and chemical properties in the field,the EM 1 component were shown to represent the far distal source aeolian sediments of the northwest monsoon dust storm and the products of the weather-ing and soil transformation,and the EM 2 component represents the proximal sediment of the loose sediment sand-storm in the northeast wind blown Yellow River flood plain.The EM 3 components represented the sediments of the suspended sediment of the river flood in the high water level stagnation environment,and the EM 4 components were the floodplain water of the river in the channel Sediment under dynamic action.This shows that the end member analy-sis of the whole sample grain size can more clearly reflect the diverse sedimentary dynamic characteristics of the Ruhe River Basin.This study has important scientific significance for a profound understanding of the evolution of the Holo-cene environment and surface processes in the Huaihe River Basin.
loesspaleosolpalaeofloodgrain size end member analysisHoloceneHuaihe River
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