不同形态河谷沉积物中稀土元素的粒径分布特征  

Particle Size Distribution Characteristics of the Rare Earth Elements in Sediment from Different Shapes of River Valleys

作　　者：尚月婷 张加琼[1,2] 白茹茹 SHANG Yueting;ZHANG Jiaqiong;BAI Ruru(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100

出　　处：《土壤学报》2024年第3期746-756,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(42077068)资助。

摘　　要：稀土元素(REE)作为一种重要的土壤侵蚀示踪元素,明确其含量随土壤颗粒粒径的变化特征,对准确量化土壤侵蚀速率具有重要意义。本研究基于Samonova等采样测定的不同粒径范围(<1、1~10、10~50、50~250和250~1 000μm)土壤/沉积物颗粒中的REE含量,分析了俄罗斯普罗特瓦河左岸河谷形态(“U”和“V”形谷)、地貌部位(坡面、沟坡/沟壁、沟道底部和洪积扇)、侵蚀(坡面、沟坡/沟壁)和沉积(沟道底部和洪积扇)环境对土壤/沉积物REE含量、富集系数等的影响。结果表明:(1)“U”和“V”形谷四类地貌下,轻稀土(LREE)、重稀土(HREE)和总稀土(ΣREE)含量均随颗粒粒径变粗呈降低趋势。在相同地貌部位,“U”形谷细颗粒(<50μm)中LREE、HREE和ΣREE含量较“V”形谷分别低14.6%~24.7%、10.0%~33.5%和14.2%~21.1%。(2)无论河谷形态和地貌部位,LREE和HREE均明显富集在细颗粒中,尤其是“V”形谷,LREE和HREE主要富集在<10μm的颗粒中。(3)对比侵蚀和沉积区,“U”和“V”形谷沉积区细颗粒中LREE和HREE的富集程度均显著(P<0.05)大于侵蚀区。可见,无论河谷形态、地貌部位和侵蚀沉积区,REE均主要富集在细颗粒中;但河谷形态和侵蚀、沉积对REE含量的粒径分布有重要影响。【Objective】Rare earth elements(REE)are one of the most important tracers in soil erosion study.Understanding the content variation of REEs alongside particle size ranges is significant to accurately quantify soil erosion rates.【Method】Based on the REE contents in different particle size ranges(<1,1-10,10-50,50-250 and 250-1000μm)of soil/sediment samples measured by Samonova et al.(2020),this study analyzed the effects of valley morphology,landforms,erosional and depositional areas on the contents and enrichment coefficient of REE in soil/sediment at the left bank of the Protva River in Russia.Landform types including hillslope,gully slope/wall,valley bottom and alluvial fan,were separately selected from a“U”and a“V”shape valley,respectively.These four landforms were further classified into erosional(i.e.,hillslope and gully slope/wall)and depositional areas(i.e.,valley bottom and alluvial fan).【Result】The results showed that:(1)The contents of light rare earth elements(LREE),heavy rare earth elements(HREE)and total rare earth elements(ΣREE)were all decreased with the increase of particle size ranges under the four landform types of“U”and“V”shape valleys.Under the condition of the same landform types,the contents of LREE,HREE andΣREE in fine particles(<50μm)of the“U”shaped valley were 14.6%-24.7%,10.0%-33.5%and 14.2%-21.1%lower than those of the“V”shaped valley,respectively.(2)Both LREE and HREE were enriched in fine particles at all landform types for both“U”and“V”shape valleys.Particularly for the“V”shape valley,LREE and HREE were significantly enriched in<10μm particles.(3)Comparing the erosional and depositional areas,the enrichment degree of LREE and HREE in the fine particles of the depositional areas in both“U”and“V”shape valleys was significantly(P<0.05)higher than that of the erosional area.【Conclusion】Accordingly,REE were enriched in fine particles regardless of river valley shapes,landforms,and erosional or depositional areas.However,both

关 键 词：侵蚀区域 沉积区域 地貌部位 轻稀土元素 重稀土元素 富集 

分 类 号：S157[农业科学—土壤学]