地质科学2024，Vol.59Issue(2)：549-561,13.DOI:10.12017/dzkx.2024.038
松嫩沙地元素和Sr-Nd同位素组成特征及其对区域粉尘物源的指示
Characteristics of element and Sr-Nd isotope composition of the Songnen sandy land and their indications of regional dust material sources
摘要
Abstract
The Songnen sandy land is located in the easternmost part of the Eurasian loess belt,and the study of its material composition is beneficial to reconstruct the glacial-interglacial dust transport pathways in the Songnen Plain.To this end,123 fluvial and eolian sand samples from the Songnen sandy land were systematically collected,geochemically analyzed for major,trace and rare earth elements and Sr-Nd isotopic compositions in different grain size fractions,and quantitatively reconstructed from the eolian dust material sources using the Frequentist model,to explore the contribution of the components of different grain size fractions in different regions of the Songnen sandy land to the loess in the Harbin and the transport paths.The results show that the Songnen sandy land has experienced a primary chemical weathering process(the mean CIA values of＜63 μm,＜30 μm,and＜10 μm fractions were 55.20,57.46,and 57.51),with a low recirculation history(the mean values of the CIA/WIP ratios for the＜63 μm,＜30 μm,and＜10 μm fractions were 0.98,1.08,and 1.04).Based on the elemental geochemistry and Sr-Nd isotope composition of the different grain size fractions,the Songnen sandy land was divided into two geochemical subzones,the northwestern and southwestern parts.The quantitative reconstruction results of the geochemical compositions of different grain size fractions showed that the contributions of different grain size fractions(＜63 μm,＜30 μm and＜10 μm)to the Harbin loess in these two subzones were 75.7%～88.5%,73.4%～84.9%and 61.0%～89.7%(southwestern part)and 11.5%～24.3%,15.1%～26.6%and 10.3%～39%(northwestern part).This study reveals that the dust transport path in the Songnen Plain since the Last Glacial Period has been dominated by the south-west direction,which differs from the circulation pattern dominated by the north-west wind during the glacial period.关键词
松嫩沙地/地球化学/Sr-Nd同位素组成/物源定量重建/哈尔滨黄土Key words
Songnen sandy land/Geochemistry/Sr-Nd isotopic composition/Provenance quantitative reconstruction/Harbin loess分类
天文与地球科学引用本文复制引用
杨珮瑶,迟云平,谢远云,康春国,孙磊,吴鹏,魏振宇..松嫩沙地元素和Sr-Nd同位素组成特征及其对区域粉尘物源的指示[J].地质科学,2024,59(2):549-561,13.基金项目
国家自然科学基金项目(编号:42171006,41601200)和黑龙江省自然科学基金项目(编号:ZD2023D003)资助 （编号:42171006,41601200）
