Hydrogeochemical analysis and identification of weathering processes to
determine the solute sources in meltwater of Chaturangi glacier, Garhwal
Himalaya, India
Abstract
This paper presents an insight on the major ion chemistry of Chaturangi
glacier meltwater and chemical weathering processes to identify ionic
sources and factors controlling the ionic composition of meltwater
during the ablation year 2015 and 2016. The analytical results show that
the meltwater is slightly acidic in nature with Mg-HCO3 and Ca-HCO3
dominated hydrochemical facies in years 2015 and 2016 respectively. In
glacier meltwater, Ca2+ is the most dominant cation and HCO3- is the
most dominant anion in both the years. Due to less anthropogenic
influence, chemical weathering of the surrounding rocks is the foremost
mechanism, controlling the hydrogeochemistry of meltwater. The gibbs
plot and mineralogy of surrounding rocks suggests that ionic
concentration of meltwater is mainly controlled by rock weathering with
little contribution from the atmosphere. A comparatively higher
contribution of (Ca+Mg) in total cations and higher elemental ratio of
(Ca+Mg)/(Na+K) (1.47±0.14) and (1.44±0.28) in year 2015 and 2016
respectively, clearly demonstrates that chemical composition is mainly
controlled by carbonate weathering and partly by silicate weathering.
Furthermore, the low elemental ratio of (Na+K)/TZ- (0.41±0.02) and
(0.22±0.05) in 2015 and 2016 respectively also suggests that carbonate
weathering is a dominant geochemical process controlling meltwater
chemistry of the study area. In addition the ion denudation rate was
also calculated for both the years. The results shows that cation
denudation rate of meltwater of Chaturangi glacier were 32.84 and 22.30
ton/km2/ablation during 2015 and 2016 respectively, whereas the anion
denudation rates were 205.43 and 170.24 ton/km2/ablation in 2015 and
2016 respectively.