ИСТИНА

The main task of this work is the development of detailed reconstructions of mountain glaciers' fluctuations with precise spatial references in the Northern Caucasus and their analyses in terms of glacier length, area and volume changes. The studied glaciers (Alibek, Ullukam, Terskol, Kashkatash, Bezingi, Mijirgi, Tsey) are situated along the Bolshoy Caucasus Range from the very west (Teberda river basin) to the east (Tsey river basin). Basing on instrumental data (since the mid of 20th century), remote sensing images (CORONA, Geoeye, Cartosat, IRS, ASTER, etc.), aerial photos of 1950s-1980s, maps (since 1887), old photographs, as well as proxy data (historical descriptions, lichenometry, dendrochronology, 14C, 10Be), we reconstructed 15-20 positions of the glaciers tongues for each glacier and produced high resolution maps showing spatial variations of the glaciers since their maximum in the mid 17th or first half of 19th century. For Alibek glacier six former front positions and elevan moraines were photo-identified and dated. We obtained the carbon dating of intermorainal peat-bog (103%), moraine dating based on isotopes of 10Be (1900±12) and determined minimum age of most distant moraine according to dendrochronological analysis of trees (Abies nordmanniana), growing on its surface (more than 200 years,). At that time (1895) the glacier was 290 m longer than today, its surface was 0.31 km2 larger (5.94 km2 in 1895, 5.63 km2 in 2008). We calculated glaciers' length and area changes, using different methods (GLIMS; Bhambri et al., 2012) and analyzed advantages and disadvantages of each method in case of their application for Caucasian glaciers. Based on our measurements we evaluated changes of equilibrium line altitude and volume. Volume changes have been reconstructed using the model offered by Lüthi et al. (2010). The results of this study are important for verification of other reconstructions with the lower spatial and temporal resolutions (Shahgedanova, 2009), they provide additional points for the growth curve of lichens in the Central Caucasus, which is poorly fixed at the moment, and are important contributions to the global paleoclimatic reconstructions (e.g. Leclercq and Oerlemans, 2011), where Caucasus is strongly underrepresented.