Assessment of solute and suspended sediments acquisition processes in the Bara Shigri glacier meltwater (Western Himalaya, India)

Abstract

Various physico-chemical parameters of meltwater samples from Bara Shigri glacier collected during 2012–2013 were analysed to understand the dissolved ion chemistry and solute acquisition processes regulating major ion chemistry of the study area. Ionic dominance of anions followed the trend as HCO3− > SO42− > Cl− > NO3−, whereas ionic dominancy of cations varied as: Ca2+> Mg2+> K+> Na+ for both the years. High share of (Ca + Mg) in the total cations and also dominancy of (Ca + Mg) over (Na + K) for both the years demonstrate that solute acquisition processes in the meltwater of Bara Shigri glacier are mainly governed by the weathering of carbonates. The Piper plot identified Ca-HCO3 as the dominant water type followed by CaSO4 type of water in the study area. The average value of partial pressure of carbon dioxide (Pco2) for meltwater of the Bara Shigri glacier was 10−2.6 atm in 2012 and 10−2.3 atm in 2013 and were higher than the Pco2 value of atmosphere (10−3.5 atm). It indicates that the meltwater is in disequilibrium with respect to the atmosphere. Contents of suspended sediment in the meltwater were 1432 mg/l in July and 596 mg/l in September 2012, whereas in 2013, suspended sediment contents were 1093 mg/l in August and 425 mg/l in September, following discharge pattern of the Bara Shigri glacier. We found that Bara Shigri and Gangotri glaciers demonstrate the higher rate of regional melting.