Deformation and recrystallization processes of ice from polar ice sheets
Deformation and recrystallization processes of ice from polar ice sheets
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极地冰盖冰的变形和再结晶过程
DOI：
10.3189/172756400781820688
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发表时间：
2000
影响因子：
2.9
通讯作者：
S. de la Chapelle
中科院分区：
文献类型：
--
作者：
P. Duval;L. Arnaud;O. Brissaud;M. Montagnat;S. de la Chapelle
摘要通过对极地冰盖深冰芯的研究，获得了有关变形模式、组构发展和重结晶过程的信息。结果表明，晶内滑动是极地冰盖的主要变形机制。晶界滑动似乎不是一个重要的变形模式。特别强调的是在冰盖的“实验室”三级蠕变的发生。蠕变行为与再结晶过程直接相关。与晶粒生长和旋转再结晶有关的晶界迁移可容纳位错滑移并抵消应变硬化。即使旋转重结晶减缓了组构的发展，组构图案也与仅由滑移引起的组构图案相似。第三期蠕变形成的组构与迁移重结晶有关，是典型的重结晶组构。它们与在温带冰川中观察到的快速边界迁移制度有关。应力指数从发生迁移再结晶时的3下降到发生正常晶粒生长时的≤ 2。
Abstract Information on deformation modes, fabric development and recrystallization processes was obtained by study of deep ice cores from polar ice sheets. It is shown that intracrystalline slip is the main deformation mechanism in polar ice sheets. Grain-boundary sliding does not appear to be a significant deformation mode. Special emphasis was laid on the occurrence of "laboratory" tertiary creep in ice sheets. The creep behavior is directly related to recrystallization processes. Grain-boundary migration associated with grain growth and rotation recrystallization accommodates dislocation slip and counteracts strain hardening. The fabric pattern is similar to that induced only by slip, even if rotation recrystallization slows down fabric development. Fabrics which develop during tertiary creep, and are associated with migration recrystallization, are typical recrystallization fabrics. They are associated with the fast boundary migration regime as observed in temperate glaciers. A decrease of the stress exponent is expected from 3, when migration recrystallization occurs, to a value ≤ 2 when normal grain growth occurs.