ИСТИНА

Dust plays an important role in Earth's system. Airborne dust, mostly emitted from soils in arid and semi-arid regions, is a key atmospheric constituent and represents an important natural source of atmospheric particulate matter. Ice cores can be considered as natural archives of data on dust in the atmosphere, they can provide information not only on amount of dust particles in the atmosphere but also give insights on strengths of the dust sources and its changes in the past. A 182 meter ice core has been recovered from a borehole drilled through the glacier to the bedrock at the Western Plateau of Mt. Elbrus (5115 m a.s.l.) in 2009. This is the first ice core in the region which represents a paleoclimate record practically undisturbed by seasonal melting. Ice samples were analysed for chemistry, concentrations of dust and black carbon, and particle size distributions. Dust mineralogy was assessed by XRD. Individual dust particles were analysed using SEM. Dust particle number concentration was measured using the Markus Klotz GmbH (Abakus) implemented into the CFA system. It was shown that desert dust deposition events occur on Mt. Elbrus 5-6 times a year. Dust originates most frequently from the Middle East, more specifically from the northern Mesopotamia and the Syrian desert. Dust form Sahara is transported to the Caucasus once or twice per year, although these events are less frequent, they result in higher dust load. The Elbrus ice core dust record correlates with the PDSI in the Levant region and can be used for the droughts reconstruction in this region. A prominent increase of dust and Ca2+ concentration was registered since the beginning of XX century with a highest dust concentration recorded in 1990-2009. Study was supported by the President Grants for Government Support of Young Russian Scientists and the Leading Scientific Schools of the Russian Federation grant № МК-2508.2017.5.