New data of deuterium excess values of glacial ice of Kamchatka

Abstract

The isotopic signature (δ18О, δ2Н, d-excess) of the ice of the Ushkovsky volcano in Kamchatka were studied. A new shallow ice core was obtained in 2022 in the Gorshkov crater. The 14 m long ice core was dated by counting annual layers, which were also compared with known eruptions in recent years. The upper 14 m of the glacier were formed over the last 16 years (from 2006 to 2022). The values of δ18О very from −16 to −24‰, δ2Н from −110,5 to −177,7‰, the averaged values are −20,5 and −150,2‰, respectively. The d-excess value varies with depth from 8,7 to 21,3‰, the average value is 13,7‰. For winter horizons at low values of δ18О and δ2Н, an increase in d-excess is noted. Such features are associated with the origin of moisture brought to Kamchatka. The source of moisture is the Pacific Ocean, the Sea of Okhotsk and the Sea of Japan, for which there are pronounced differences in the conditions of moisture evaporation between summer and winter. The increasing trends in δ18О and δ2Н values from 2006 to 2022 are accompanied by a decrease in deuterium excess, indicating an increase of summer precipitation. However, in addition to changes in seasonal proportions of precipitation, ice d-excess values may reflect climatic changes in the source of moisture.