CHEMICAL-COMPOSITION OF SNOW AND ICE FROM CHHOTA SHIGRI GLACIER, CENTRAL HIMALAYA

A systematic study of the chemical composition of snow, firn from a shallow core, surface ice and of meltwater samples collected from the Chhota Shigri glacier, Central Himalaya, is reported here. The average concentrations of Na and Cl in snow are 402 and 753 mug l-1 respectively; whereas those in old surface ice are relatively low, 185 mug l-1 and 375 mug l-1, respectively. The average Cl/Na weight ratio in these samples is almost-equal-to 1.9, quite similar to that in the sea salts suggesting that both Cl and Na are predominantly of marine origin. The concentrations of other major ions such as K, Mg, Ca, NO3 and SO4 in snow and ice samples are generally less than 1 mg l-1. The major ion concentrations, when normalized to Na, indicate that the abundances of K and Ca are dominated by terrestrial sources whereas Mg appears to have both marine and terrestrial sources. Based on the seasonal variations of Na and Cl concentrations observed in the ice core samples, an approximate accumulation rate at the core site has been estimated to be 1.6 m year-1 (640 kg m-2 year-1).