Chemical and Boron Isotope Characteristics of Snow in the Qiyi Glacier, Qinghai-Tibet Plateau

Abstract

Snow is a valuable carrier for recording atmospheric information and snowmelt constitutes a crucial hydrological resource for ecosystem sustainability and human activities. The agriculture, industry, livelihoods and ecological security in the Hexi Corridor are dependent on the support of glacier snowmelt in Qilian Mountains of Qinghai-Tibet Plateau. We investigated the main water-soluble ions, trace elements and boron isotopes composition of snow at different altitudes in the Qiyi Glacier of the Qilian Mountains from 12 to 23, Aug. 2020. It is found that Ca2+ and Cl- as the major ions contribute up to 17.08% and 22.42% of the whole ions, respectively. The average Zn concentration exceeds 10 μg/L, as the dominant heavy mental element. Water-soluble ions are mainly influenced by natural sources (salt lakes, deserts), while heavy metal elements are mainly affected by anthropogenic sources like mining activities and the discharge from industrial and agricultural production. The δ11B concentration in the Qiyi Glacier ranges from +13.47 to +22.71 ‰, with an average of +18.40‰, and it is much lower than the average marine δ11B value (+39.5‰). The contribution rate of δ11B in sea salt to dissolved boron (Bsea-salt) in Qiyi Glacier snowfall is only 0.52∼1.77%. The lower mean δ11 B value and Bsea-salt shows that B in the Qiyi Glacier snow is mainly derived from the salt lake in the Qaidam Basin. These results can extend boron isotope research field of the Qinghai-Tibet Plateau and effectively enhance cognition of glacial snow chemistry, particularly in the context of local atmospheric environmental management and ecological construction.