First geophysical and shallow ice core investigation of the Kazbek plateau glacier,Caucasus Mountains |
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| Authors: | Stanislav S Kutuzov Vladimir N Mikhalenko Alexi M Grachev Patrick Ginot Ivan I Lavrentiev Anna V Kozachek Victoria V Krupskaya Alexey A Ekaykin Levan G Tielidze Pavel A Toropov |
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| Institution: | 1.Department of Glaciology,Institute of Geography of the Russian Academy of Sciences,Moscow,Russia;2.Observatoire des Sciences de l’Univers de Grenoble (OSUG), IRD-UGA-CNRS,Grenoble,France;3.Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE),UGA-CNRS,Grenoble,France;4.Arctic and Antarctic Research Institute,St. Petersburg,Russia;5.Institute of Geology of Ore Deposits, Petrology, Mineralogy and Geochemistry of the Russian Academy of Sciences,Moscow,Russia;6.Department of Engineering and Ecological Geology, Faculty of Geology,Moscow State University,Moscow,Russia;7.Institute of Earth Sciences,Saint Petersburg State University,Saint Petersburg,Russia;8.Department of Geomorphology, Vakhushti Bagrationi Institute of Geography,Ivane, Javakhishvili Tbilisi State University,Tbilisi,Georgia;9.Department of Meteorology and Climatology, Faculty of Geography,Moscow State University,Moscow,Russia |
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| Abstract: | First-ever ice core drilling at Mt. Kazbek (Caucasus Mountains) took place in the summer of 2014. A shallow ice core (18 m) was extracted from a plateau at ~4500 m a.s.l. in the vicinity of the Mt. Kazbek summit (5033 m a.s.l.). A detailed radar survey showed that the maximum ice thickness at this location is ~250 m. Borehole temperature of ?7 °C was measured at 10 m depth. The ice core was analyzed for oxygen and deuterium isotopes and dust concentration. From the observed seasonal cycle, it was determined that the ice core covers the time interval of 2009–2014, with a mean annual snow accumulation rate of 1800 mm w. eq. Multiple melt layers have been detected. δ18O values vary from ?25 to ?5‰. The dust content was determined using a particle sizing and counting analyzer. The dust layers were investigated using scanning electron microscopy and X-ray diffraction analysis. Dust can be separated into two categories by its origin: local and distant. Samples reflecting predominantly local origin consisted mainly of magmatic rocks, while clay minerals were a characteristic of dust carried over large distances, from the deserts of the Middle East and Sahara. The calculated average dust flux over three years at Kazbek was of 1.3 mg/cm2 a?1. Neither δ18O nor dust records appear to have been affected by summer melting. Overall, the conditions on Kazbek plateau and the available data suggest that the area offers good prospects of future deep drilling in order to obtain a unique environmental record. |
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