天山乌鲁木齐河源1号冰川融水径流水化学特征研究

2006年和2007年的整个消融期内,在天山乌鲁木齐河源1号冰川末端水文控制点逐日定时采集融水径流样品,对样品的主要可溶离子、pH、电导率EC、总溶解固体TDS和悬移质颗粒物SPM进行了分析.结果表明:天山乌鲁木齐河源1号冰川融水径流离子类型为Ca2+-HCO-3-SO2-4,呈弱碱性.融水径流中TDS变化受日径流量调节显著,表现为消融初期和末期浓度较高,消融强烈时浓度较低;SPM以细颗粒物质为主,各粒度组分含量变化幅度较大,且质量浓度SSC年内变化与TDS呈相反的变化趋势.融水径流中离子组成主要受岩石风化作用影响,离子摩尔比值和Piper图分析表明,控制冰川径流离子组成的主要过程是碳酸盐、黄铁矿和长石类矿物风化作用.

A study of hydrochemical characteristics of meltwater runoff of the Ürümqi Glacier No. 1, Tianshan Mountains

The aim of this study is to investigate the hydrochemical characteristics of the meltwater runoff of Ürümqi Glacier No. 1 in the Tianshan Mountains. The 2-year continuous meltwater samples, taken in the ablation seasons of 2006 and 2007, were analyzed for major cations(Mg²⁺, Ca²⁺, Na⁺, and K⁺)and anions(SO₄^2-, NO₃ ^-and Cl^-), pH, electrical conductivity(EC), total dissolved solids(TDS)and suspended particulate matter(SPM). The results revealed that calcium is the dominant cation, while bicarbonate and sulphate are the dominant anions. The concentrations of cations vary as c(Ca²⁺)>c(Mg²⁺)>c(K⁺)>c(Na⁺), while the order for the anions is c(HCO₃^-)>c(SO₄^2-)>c(NO₃^-)>c(Cl^-). The glacial meltwater is slightly alkaline with the mean pH of 7.74 and 7.61 in 2006 and 2007, respectively. The TDS values in runoff samples have an inverse relationship with the diurnal discharge, while the suspended sediment concentration(SSC)shows a positive correlation with discharge. From the results of Gibbs distribution pattern, it is concluded that the major origin of ions in runoff is the weathering of rocks. Based on the ion ratios and the piper trilinear nomograph, it is found that the main processes are carbonate weathering, pyrite weathering and feldspar weathering, and Ca²⁺ and HCO₃^- are the dominant cation and anion during the carbonate weathering process.