[Chemical denudation rates and carbon dioxide sink in Koxkar glacierised region at the south slope of Mt. Tianshan, China].

Chemical denudation rates and carbon dioxide sink were from water samples from ice-melt water, precipitation and river water were collected daily from June 21st to September 10th in 2004 in the Koxkar glacier region, south slope of Mt. Tianshan, China. The law of conservation of mass was applied for calculating chemical denudation fluxes and transient carbon dioxide sink. It is found that: 1) There were average of 60.7 kg x (km2 x d)(-1) and 60.2 kg x (km2 x d)(-1) solutes supplied by precipitation and ice melt-water respectively which accounted for about 7.7% and 7.6% of the total solutes of bulk river water [791.2 kg x (km2 x d)(-1)]. Consequently, the rate of chemical denudation derived from the crustal flux was 558.0 kg x (km2 x d)(-1), accounting for 70.5%. 2) Carbonation weathering was 308.9 kg x (km2 x d)(-1), and heavier than that of the other chemical denudations. The crustal concentration of bicarbonates (HCO3-) is attributed chiefly to the carbonation of carbonates (limestone and dolomite) and aluminosilicates/silicates. A further important source of bicarbonates and sulphates is pyrite oxidation coupled with limestone/dolomite dissolution. The transient carbon dioxide sink can be estimated by ion balance law, which is 81.0 kg x (km2 x d)(-1), accounting for 14.2%. 3) The chemical denudation rates was 641.1 kg x (km2 x d)(-1) with relationship of specific conductivity to concentrations of dissolved carbonate in water, which is only 4.4% less than that obtained from mass balance method without regard to carbon dioxide sink. The study also implied important to evaluate chemical denudation fluxes of poor data in western mountain area, China. However, because of without chemical analysis and ion partitioning, the transient CO2 drawdown cannot be established.

[Hydrochemical characteristic analysis of melting water flow in Keqikaer Glacier, Tianshan (west) Mountains].

In order to study the melting water chemical characteristics in the Keqikaer Glacier, Tianshan(west)Mountains, the samples were collected from June to September in 2003. The result is found that: (1) The pH value is between 7.35-8.52, the order of which is:river water > glacier melting water > lake water on glacier > precipitation. (2) The various ionic concentrations of melting water are lower than other three kinds of samples, and average is 24% of river water. (3) Comparing and analyzing hydrochemical difference among various precipitation forms, the author found that inhomogeneous ionic concentration of rainwater is higher than the others. (4) Next, the water samples at different altitude have been analyzed, which shows that inhomogeneous ionic concentration of altitude effect is very remarkable. It is expected that if altitude is lower, the eluviation is led by glacier melting can influence the enviro-information record of ice layer.