额尔齐斯河源春季水化学及稳定同位素特征研究

Study on the hydrochemical and stable isotope characteristics at the headwaters of the Irtysh River in spring

基于2018年4月额尔齐斯河源至富蕴段的河水样品,综合运用Gibbs图、Piper三线图、相关矩阵分析等方法对河水中主要的化学离子、pH值、电导率、TDS和氢、氧稳定同位素等物理化学指标进行了分析。结果表明:额尔齐斯河源春季河水呈弱碱性,TDS平均值为72.02mg·L^-1,整体属于低矿化度水。河水中主要离子浓度序列为HCO3^->SO4^2->Ca^2+>Na^+>Cl^->NO3->Mg^2+>K^+,其中HCO3^-、SO4^2-和Ca^2+是最主要的阴阳离子。水化学类型从库依尔特河的HCO3^--Ca^2+型转变为额尔齐斯河富蕴段的(HCO3^-,SO4^2-)-Ca^2+型。从源区至富蕴段各离子含量整体呈增大趋势,但其增加过程受到复杂因素的影响而出现差异。河水离子主要受水-岩风化作用控制,且以碳酸盐岩(石灰岩、白云岩)为主的风化水解是离子的主要来源,其次是长石类矿物的风化,还包括下游人类活动的离子输入等。δD和δ18O沿程逐渐增大,在下游出现了富集现象。

Based on the water samples,collected from the headwaters to Fuyun stream segment of the Irtysh River in April 2018,this study analyzed the hydrogen and oxygen stable isotopes and physicochemical indices[including major chemical ions,pH,electrical conductivity,total dissolved solids(TDS)etc.]by using Gibbs diagram,Piper three-line diagram and correlation matrix analysis comprehensively.Results show that river water presents weak alkalinity and belongs to low salinity water,with a mean TDS of 72.02 mg·L^-1 in spring.The rank order for major ions is HCO3^->SO4^2->Ca^2+>Na+>Cl^->NO3^->Mg^2+>K^+,of which HCO3^-,SO4^2-and Ca^2+are the major anions and cations.Hydrochemical type of the river water changes from HCO3^--Ca^2+to(HCO3^-,SO4^2-)-Ca^2+from the Kuyrte River to the Fuyun stream segment of the Irtysh River.The ion content increases with flow extension and increases in touching-time with riverbed,but this process has difference due to effect of various factors.River water ions are mainly controlled by water-rock weathering,which are mainly originated from weathering and hydrolysis of carbonate rocks,weathering of feldspar minerals and downstream human activities.TheδD andδ18O increase gradually along the river and enrichment phenomenon occurs in downstream.