Hydrochemical Characteristics In The Glacier No.72of Qingbingtan, Tomur Peak

Glacier area located in the alpine zone, is affected limitedly by direct humanactivities, and the content of various chemical substances in water represents thebackground value of the hydrological and chemical effected without human activitiesin nature, the chemical composition and evolution process of which directlyreflecting the hydrogeological characteristics in the basin and flowing through theregion. The Tianshan Tomur Peak region is the largest glacier area in number andscale. However, so far, the domestic study about hydrochemistry in the region is stillvery limited. So carrying out the discuss of hydro-chemical action on the Tomur Peakglacial meltwater is very significant, not only helping us understand water qualitychanges in mountain river under the future climate conditions, can also paving for theresearch of interaction between the atmospheric environment and mountain ecologicalenvironment. Based on31streamwater samples collected at the Glacier No.72ofQingbingtan from1st to31st August2008, and snow pit data and rock samples in thestudy region, the study discusses the hydrochemical characteristics and the ion source.The main conclusions are as follows.（1） The anions and cations in streamwater of glacier No.72are dominated byHCO₃^-and Ca²⁺. The order of cations are: Ca²⁺＞Na⁺＞Mg²⁺＞K⁺＞NH₄⁺. The orderof anions are: HCO₃^-＞SO₄^2-＞Cl^-＞NO₃^-. The order of major ion concentrations was:HCO₃^-> SO₄^2-> Ca²⁺> Cl^-> Na⁺> NO₃^-> Mg²⁺> K⁺> NH₄⁺. The ion composition instreamwater of glacier No.72of Qingbingtan is in accordance with upstream on thesouthern slope in Tomur Peak region. The major ion concentrations varied similarly,the positive correlation being obvious, but the correlation between NO₃^-and the othersbeing worse. The precipitation and ion concentrations have an apparent positivecorrelation, which indicate the river ion concentrations influenced by theprecipitation-effected water-rock exchange of ions with the debris cover and thelateral ridge area, as well as the air temperature. Negative correlation was foundbetween discharge of river and ion concentrations.（2） Gibbs figure shows that the main factors controling ion changes in the river are rock and soil weathering （water-rock exchange process）, and other factors are in asecondary position. Principal component analysis and correlation analysis resultsshow that the ion sources can be subdivided into three categories, the first category isthe local sources, including Cl-、Na+、K+、Mg2+、HCO3-and SO42-; second categoryis NO3-with the special source, largely unaffected by the influence of other ions; thirdcategory is Ca2with complex sources. To further analyze by the Piper figurecombining with ion composition ratio, the result show that a large number ofmoraines and rock around glaciers and the riverbed are siliceous schist, which ions inthe runoff mainly come from the carbonate （calcite）, pyrite, feldspar and biotitemineral weathering, water chemical reaction between carbonate and pyrite to promotegrowth. Atmospheric precipitation produces dilution effect on runoff, increases therunoff flow, strengthens the water-rock interaction, and increases the ion content inthe runoff, and dust storms can affect the ion concentration in the runoff, atmosphericinput is a sudden event. The influences of meltwater affecting water chemicalcharacteristics in the runoff can not be ignored.