A variation of stable isotope composition of snow with altitude on the Elbrus mountain, Central Caucasus

摘要

This study aims to analyze the stable isotope composition of the snow cover of the Elbrus Mountain – the highest mountain in Europe. Snow sampled in the middle accumulation period in January 2017, February 2016, January 2001 and during snowmelt in July 1998 and August 2009. Snow sampled at the south slope of Mt. Elbrus at different elevations, and the total altitude range is approximately 1700 m. A significant altitude effect in fresh snow precipitation was determined in February 2001 with gradient –1.3‰ δ18O/100 m (–11.1‰ δ2 H /100 m) at 3100-3900 m a.s.l. and inverse altitude effect in February 2016 with gradient +1.04‰ δ18O /100 m (+8.7‰ δ2 H /100 m) at 3064-3836 m a.s.l. There is no obvious altitude effect of the δ2 H and δ18O values in snow at the Elbrus slope in 2017, except for the height range 2256-3716 m a.s.l., where altitudinal effect of δ18O values was roughly -0.32‰/100m. The δ18O values in the winter snowpack in some cases decrease with increasing altitude, but sometimes are not indicating a temperaturealtitude effect. Post-depositional processes cause isotopic changes, which can result from drifting, evaporation, sublimation, and ablation. The study of altitude effect in snow is important for understanding the processes of snow-ice and snow-meltwater transformation and the snow/ice potential to provide paleo-environmental data.