Chapter 19 - Holocene glacier variations in the Northern Caucasus, Russia

Abstract

More than 1500 glaciers exist on the northern (European) side of the Greater Caucasus. Until recent times, the ages of the Holocene moraines in the Caucasus were based on fragmented information (14C, historical, tree-ring and lichenometry data) that mainly covered the Late Holocene. Available 10Be dates of moraines are still very limited in number and are not well replicated. However, even these very preliminary data have allowed for the first time identification of the age of some Holocene moraines in Caucasus at the glaciers Alibek (western Caucasus), Greater Azau, Irik, Schkelda, Terskol, Kashkatash, Donguz-Orun (Elbrus area, central Caucasus) and Bezengi (Cherek Bezengiisky valley, central Caucasus). According to these 10Be age estimates, the glacier advances occurred at c. 10.9, 7.0–6.6.6, 3.0–2.9, 1.6, 0.7–0.8, 0.5, 0.25 and 0.16–0.14ka. The Early Holocene advance is documented in one valley (Terskol) and the date needs confirmation. Surprisingly, we identified a possible prominent advance of Bezengi Glacier in the warm period at c. 6ka. The moraines yielding 10Be ages younger than 1.6ka in the Elbrus region usually represent a compound complex consisting of several ridges that directly contact the moraines of the LIA maximum. The 10Be dates of the two advances at 2.9ka and CE 1840s–1860s are supported by the other independent geochronological and stratigraphic data (14C dates of palaeosols at Greater Azau Glacier). The younger glacier maximum is also confirmed by historical and tree-ring data (CE 1840s). Since the middle of 19th century, the glaciers in the Caucasus are retreating.