2:30 PM - 2:45 PM
[ACC26-04] Layering structures and deformation regime at the deeper part of Dome Fuji –Investigations of physical layering strucutres leading to Oldest ice–
Keywords:Dome Fuji ice core, layering structure, deformation regime
In the physical properties of ice-sheet ice, the crystal orientation fabric (COF) is one of the important parameters since the development of COF highly affects the deformation and flow of ice sheets. At depths shallower than 2400 m in the Dome Fuji ice core, layering structures of the COF are investigated by author’s group. They revealed that 1) the degree of c-axis clustering in warmer periods is decreased and 2) the factors determining the deformation of ice include the concentration of chloride ions and the amount of dust particles.
To understand the layering structures and deformation regime at deeper part in the ice sheet, we performed physical analyses using the Dome Fuji ice core at depths greater than 2400 m. From the dielectric tensor measurements and microstructural observations using ice thin sections, we found that the development regime of the COF was changed significantly around 2400 m depth. Additionally, the variation trend of the COF associated with the increase of dust particle concentration was changed at deeper parts. These results indicates that the deformation regimes at deeper part are greatly different from those at shallower parts due to the influence of bedrock.