现代地质2024，Vol.38Issue(2)：487-496,10.DOI:10.19657/j.geoscience.1000-8527.2023.119
青海湖湖东地区近32 ka BP以来风沙沉积的粒度端元特征及环境意义
Grain Size End-member Characteristics of the Aeolian Sediments in the East of Qinghai Lake and Its Environmental Significance Since 32 ka BP
摘要
Abstract
The typical aeolian sediments in the eastern part of Qinghai Lake are sensitive to climate changes,and these sediments provide an ideal window for the reconstruction of the paleoclimate environments.In this study,we selected an eolian sand-sandy paleosoil profile with a thickness of 10 m in the eastern area of Qinghai Lake as the study area.An end-member analysis model is used to analyze the data of sediment grain size,and the grain size components which are sensitive to climate changes are extracted thereafter.We combined the grain size and magnetic susceptibility indexes in our data analysis.We further discussed the environmental sig-nificance of each end-member indication and the environmental evolution in the eastern Qinghai Lake since 32 ka BP.The results show that the grain size component of the Dashuitang profile is mainly sand,and followed by silt,and the least is clay.The grain size components of sediments can be decomposed into three end-members:EM1,EM2,and EM3.EM1 is the sensitive grain size affected by winter monsoon,indicating the change of the strength of the winter monsoon.EM2 indicates the strength of regional environment affected by aeolian sand,which opposites to EM1.EM3 indicates sediment transport in the form of dust storms under the influence of a regional low-level wind system.The environmental evolution of the study area can be divided into four stages.During the last interglacial stage(32-23.2 ka BP),the climate was humid and the aeolian activities were rel-atively weak.During the last glacial maximum stage(23.2-15.8 ka BP),the climate was cold and dry,and the aeolian activities became stronger.During the last glacial deglaciation stage(15.8-9.5 ka BP),the cli-mate was still mainly cold and dry,and the cold and warm fluctuated,but there is a small wave of warming.In the Holocene(since 9.5 ka BP),the climate fluctuated significantly.It was warm in the early period,warmest in the middle period,and cool in the late period.关键词
端元分析/风成砂/环境演变/青海湖Key words
end-member analysis/aeolian sand/environmental evolution/Qinghai Lake分类
天文与地球科学引用本文复制引用
胡梦珺,许澳康,孙文丽,庄静..青海湖湖东地区近32 ka BP以来风沙沉积的粒度端元特征及环境意义[J].现代地质,2024,38(2):487-496,10.基金项目
国家自然科学基金项目(41171018和41161036). （41171018和41161036）
