ИСТИНА

Knowledge of the ice thickness and volume of glaciers in the mountainous areas is very limited. Here we present a GPR study on a western Elbrus plateau (Central Caucasus) situated at elevation 5100 - 5150 m a.s.l. This site represents one of the most valuable paleo archives as revealed by deep ice core drilling in 2009 and next drilling is planned for 2018. Low-frequency ground-based radar survey was performed in summer of 2017 to improve existing data on ice thickness and bedrock topography over western Elbrus plateau. For this purpose, 20 MHz VIRL-7 monopulse ice-penetrating radar was used. The GPR control unit, the receiver, transmitter and the Gamin GPS receiver were mounted on backpacks and carried by group of 3 people. In total, we measured the glacier depth at more than 15 000 sounding points along 6 km profiles, with an estimated accuracy of ice thickness measurements of 2%. A detailed ice thickness distribution map and bedrock topography was obtained. The latter was constructed as a difference between ice surface DEM from the Pléiades stereo-pair on 8.09.2017 and ice thickness data. The average thickness over the plateau the investigated part of the plateau is 151 m, with maximum value of 260±8 m. The obtained data will be used as a basis for depth age and ice flow modelling and choosing the best location for future deep ice core drilling. This study was supported by Russian Scientific Foundation, Grant №17-17-01270.