Kutuzov S. S., Mikhalenko V. N., Grachev A. M., Ginot Patrick, Lavrentiev II, Kozachek A. V., Krupskaya V. V., Ekaykin A. A., Tielidze L. G., Toropov P. A. (2016). First geophysical and shallow ice core investigation of the Kazbek plateau glacier, Caucasus Mountains. Environmental Earth Sciences, 75 (23), p. art. 1488 [15 p.]. ISSN 1866-6280.
Titre du document
First geophysical and shallow ice core investigation of the Kazbek plateau glacier, Caucasus Mountains
Kutuzov S. S., Mikhalenko V. N., Grachev A. M., Ginot Patrick, Lavrentiev II, Kozachek A. V., Krupskaya V. V., Ekaykin A. A., Tielidze L. G., Toropov P. A.
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 similar to 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 similar to 250 m. Borehole temperature of -7 degrees 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. delta O-18 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/cm(2) a(-1). Neither delta O-18 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.
Plan de classement
Sciences du milieu [021]
;
Hydrologie [062]
;
Géologie et formations superficielles [064]
