Chemistry of snow and ice cores along the ice flow lines at Lake Vostok (Antarctica)

摘要

The authors present the results of high resolution chemical studies of snow cover from pits and cores along the ice flow lines from Ridge B to Lake Vostok across its southern (profile VFL) and northern (profile NVFL) parts. The sampling was performed between 2006-2013 during the seasonal 52nd-57th Russian Antarctic expeditions (RAE). Chemical signals of non-sea-salt sulphates and an analysis of the morphology, size and composition of microparticles allowed for the identification of the products of large volcanic eruptions during the 19th and 20th centuries, including the eruptions of Tambora (1815), Krakatoa (1883), Agung (1963) and Pinatubo (1991). In the layers with high non-sea-salt sulphate concentrations, we found small aluminosilicate particles with K, Fe and Mg inclusions, which could be of volcanic origin. Using volcanic markers, we calculated snow accumulation rates for the past 200 years along the two ice flow lines. The maximal snow accumulation rates (33mm in water equivalent yr(-1)) were found in the northern ice flow line, and the minimal rates (25mm in water equivalent yr(-1)) were found in the southern ice flow line.