元データ 国立極地研究所


Mechanical property studies have been conducted on deep ice core samples to understand the flow dynamics of large polar ice sheets. Uniaxial compression tests were done both on the Dye 3 and GRIP ice core samples from Greenland. The stress axis is inclined 45 degree from core axis in order to have information on horizontal shear deformation behavior of an ice sheet. The results were analyzed by using an enhancement factor, E. C-axis orientation fabric is a dominant factor for E values and can be estimated from vertical compression strain (N. AZUMA and A. HIGASHI, 1985) if preferred orientation is developed by crystal rotation process without recrystalization. E values from Dye 3 and GRIP samples were plotted with normalized depth (=depth/ice thickness), which is a measure of vertical compression strain. Down to a depth around 60% of ice thickness, the E value stays constant around l, and increases below that depth as expected from the single maximum fabric in deeper places. Below a depth around 70% of ice thickness, E exceeds about 10 and E of GRIP ice samples is higher than that of Dye 3 samples in general. This difference could be attributed to chemical impurity contents and/or ice stratigraphic features such as cloudy bands.


Watanabe Okitsugu National Institute of Polar Research, Research Organization of Information and Systems
Narita Hideki Institute of Low Temperature Science Pan-Okhotsk Research Center, Hokkaido University
宮本 淳 北海道大学低温科学研究所
Miyamoto Atsushi Kitami Institute of Technology
Watanabe O National Institute Of Polar Research Research Organization Of Information And Systems
Watanabe Okitsugu National Institute Of Polar Research
Narita Hideki Institute Of Low Temperature Science Pan-okhotsk Research Center Hokkaido University
Clausen Henrik Department Of Cellular And Molecular Medicine University Of Copenhagen
Shoji Hitoshi Department Of Applied Physics Faculty Of Engineering Hokkaido University
Narita Hideki Institute Of Low Temperature Science Hokkaido University
Watanabe Okitsusgu National Institute of Polar Research
MIYAMOTO Atsushi Institute of Low Temperature Science, Hokkaido University
KIPFSTUHL Josef Alfred-Wegener-Institut fur Polar- und Meeresforschung, Columbusstrasse
Kipfstuhl Josef Alfred-wegener-institut Fur Polar- Und Meeresforschung Columbusstrasse