Insights into the provenance implication of leaf wax n-alkanes along the lower Yellow River  

作　　者：Liang ZHANG Jinzhao LIU Chong JIANG Fei ZHANG Zhisheng AN 

机构地区：[1]School of Human Settlements and Civil Engineering,Xi’an Jiaotong University,Xi’an 710054,China [2]State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China [3]National Observation and Research Station of Earth Critical Zone on the Loess Plateau of Shaanxi,Xi’an 710061,China

出　　处：《Science China Earth Sciences》2024年第6期2001-2018,共18页中国科学（地球科学英文版）

基　　金：supported by the Chinese Academy of Sciences(Grant No.ZDBSLY-DQC033);the National Natural Science Foundation of China(Grant Nos.42073017&42030512)。

摘　　要：Serving as one of the largest rivers in terms of both sediment and organic carbon transport fluxes in the world,the Yellow River plays a crucial role in regional biogeochemical process as well as in the global carbon cycle.However,although a large number of studies have been carried out on the flux,composition,source and seasonal variation of total particulate organic carbon in the Yellow River so far,studies on molecular biomarkers at different spatial and temporal scales are still scarce.In this study,we focus on the molecular and hydrogen isotopic properties of leaf wax n-alkanes among different types of samples which obtained from different seasons(flood vs.non-flood)along the lower Yellow River.The molecular distribution of n-alkanes show that the riparian topsoils are subject to inputs from the overlying vegetation,while the suspended sediments from the flood season are characterized by the mixing of soil materials which originate from various stratigraphy with different ages on the Chinese Loess Plateau.Due to the contrasting hydrodynamic conditions,the n-alkanes in suspended sediments also show distinct molecular composition between flood and non-flood seasons.Additionally,considering the effect of climatic factors,the proportion of monocots in flood-season suspended sediments is calculated from a semi-quantitative perspective using δ^(2)H_(wax).Our findings may bring to light new considerations for the interpretation of leaf wax proxies in studies of organic matter sources of Yellow River.

关 键 词：Molecular distribution Hydrogen isotopic composition Leaf wax n-alkanes Suspended sediments Lower Yellow River 

分 类 号：P593[天文地球—地球化学]