Investigation of a deep ice core from the Elbrus western plateau, the Caucasus, Russia

• Published in: The Cryosphere
• Main Authors: Mikhalenko, V, Sokratov, S, Kutuzov, S, Ginot, P, Legrand, Michel, Preunkert, S, Lavrentiev, I, Kozachek, A, Ekaykin, A, Faïn, X, Lim, S, Schotterer, U, Lipenkov, V, Toropov, P
• Other Authors: Institute of Geography, Russian Academy of Sciences Moscow (RAS), Arctic Environment Laboratory, Lomonosov Moscow State University (MSU), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Arctic and Antarctic Research Institute (AARI), Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet), Climate and Environmental Physics Bern (CEP), Physikalisches Institut Bern, Universität Bern Bern -Universität Bern Bern
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDE]Environmental Sciences; ice core; The Cryosphere
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-01349498; https://hal-insu.archives-ouvertes.fr/insu-01349498/document; https://hal-insu.archives-ouvertes.fr/insu-01349498/file/CRYOSPHERE%20-%20%20Investigation%20of%20a%20deep%20ice%20core%20from%20the%20Elbrus%20western%20plateau%20the%20Caucasus%20Russia.pdf; https://doi.org/10.5194/tc-9-2253-2015

International audience A 182 m ice core was recovered from a borehole drilled into bedrock on the western plateau of Mt. Elbrus (43 • 20 53.9 N, 42 • 25 36.0 E; 5115 m a.s.l.) in the Cauca-sus, Russia, in 2009. This is the first ice core in the region that represents a paleoclimate record that is practically undisturbed by seasonal melting. Relatively high snow accumulation rates at the drilling site enabled the analysis of the intraseasonal variability in climate proxies. Borehole temperatures ranged from −17 • C at 10 m depth to −2.4 • C at 182 m. A detailed radio-echo sounding survey showed that the glacier thickness ranged from 45 m near the marginal zone of the plateau up to 255 m at the glacier center. The ice core has been analyzed for stable isotopes (δ 18 O and δD), major ions (K + , Na + , Ca 2+ , Mg 2+ , NH + 4 , SO 2− 4 , NO − 3 , Cl − , F −), succinic acid (HOOCCH 2 COOH), and tritium content. The mean annual net accumulation rate of 1455 mm w.e. for the last 140 years was estimated from distinct annual oscillations of δ 18 O, δD, succinic acid, and NH + 4. Annual layer counting also helped date the ice core, agreeing with the absolute markers of the tritium 1963 bomb horizon located at the core depth of 50.7 m w.e. and the sulfate peak of the Katmai eruption (1912) at 87.7 m w.e. According to mathematical modeling results, the ice age at the maximum glacier depth is predicted to be ∼ 660 years BP. The 2009 borehole is located downstream from this point, resulting in an estimated basal ice age of less than 350–400 years BP at the drilling site. The glaciological and initial chemical analyses from the Elbrus ice core help reconstruct the atmospheric history of the European region.