Bi-polar studies on physical and mechanical properties of deep ice cores

极地冰盖包含了地球上的古环境变化记录。本研究旨在通过对格陵兰(GRIP和NGRIP核)和南极(Dome Fuji核)冰盖进行对比研究，研究冰盖的物理和力学特征，为从深部冰芯提取环境信号奠定基础。主要成果总结如下：1)为了研究冰晶的滑移系统，参照提拉法，在实验室中设计并建造了一台大型单晶冰晶生长装置。对获得的冰样进行了单轴压缩试验。锥面滑动的流动应力比以往假定的要大得多。2)格陵兰岛GRIP和南极富士穹顶深部岩心样品的单轴压缩实验表明，冰流强度只取决于c轴分布，而与杂质含量无关。3)对格陵兰岛NGRIP和GRIP冰芯样品云带结构的微观观测表明，微泡是主要的光散射源，并首次测量了云带的数密度和尺寸分布。

Polar ice sheets contain palaeo-environmental variation records on the Earth. This study aims to investigate physical and mechanical characteristics of ice sheets by conducting comparative studies of Greenland (GRIP and NGRIP cores) and Antarctic (Dome Fuji core) ice sheets, which serve as a foundation to retrieve environmental signals from deep ice cores. Major outcomes are summerized as below.1) To investigate slip systems of ice crystal, a growth apparatus for a large single ice crystal was designed and constructed in a laboratory in reference to the Czochralski method. Uniaxial compression tests were carried out with ice samples obtained. Flow stress for pyramidal plane sliding is much higher than those hitherto assumed. This suggest that pyramidal plane sliding may not be contributing to ice sheet flow.2) Uniaxial compression tests on deep core samples from GRIP, Greenland and Dome Fuji, Antarctica revealed that ice flow strength depends only on c-axis distribution, and not on impurity contents. This suggests that ice sheet flow strength may be calculated by adopting some models for fabric evolution in ice sheets.3) Microscopic observations on cloudy band structures in ice core samples from NGRIP and GRIP, Greenland revealed that major sources for light scattering are micro-bubbles and the number density and size distribution were measured for the first time.