Source characteristics and environmental significance of grain size end members indicators in Republican Basin during Middle and Late Holocene
The sediment accumulation process in the Republican Basin is a good record of the changes in the Asian monsoon and westerly circulation,which is of great value in revealing the characteristics of the material sources and the environmental evolution.In this study,a typical aeolian-Paleosol profile with a thickness of 280cm in the Republican Basin was selected,and its grain-size data were parametrically endogenously decomposed to explore the sediment transport dynamics,transport modes,and environmental information.The following conclusions can be drawn:1)The sediment grain size component of the MS profile can be decomposed into three end members:EM 1 represents remote source dust material transported by high altitude air currents and can be used indirectly as a proxy for summer monsoon.EM2 is indicative of near source dust transported over short distances by leaps or suspensions,and EM3 is a near source coarse-grained material,which together are indicative of changes in the strength of winter winds.2)The environmental evolution of the Republican Basin during the Middle and Late Holocene can be divided into four stages:About 8.0～4.78 ka BP period,the climate was warm and humid,with weak aeolian activities,4.78～2.90ka BP period,the climate was cooler and drier,with frequent aeolian activities,2.90～0.67ka BP period,the climate was relatively warm and humid,0.67 ka BP to present,with a cooler and drier climate and increased aeolian activities.The dust accumulation process was also constructed based on environmental information to recognize that the dust accumulation process plays an important role in carrying out sand and dust management.
end member analysismaterial source characteristicsMiddle to Late Holoceneenvironmental evolutionRepublican Basin
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