Ice-age ice-sheet rheology: constraints from the Last Glacial Maximum form of the Laurentide ice sheet
Ice-age ice-sheet rheology: constraints from the Last Glacial Maximum form of the Laurentide ice sheet
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冰河时代冰盖流变学：末次盛冰期劳伦泰德冰盖形式的限制
DOI：
10.3189/172756400781820859
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发表时间：
2000
影响因子：
2.9
通讯作者：
L. Tarasov
中科院分区：
文献类型：
--
作者：
W. R. Peltier;D. Goldsby;D. Kohlstedt;L. Tarasov
摘要现代格陵兰冰盖和末次冰盛期覆盖加拿大的古老劳伦蒂德冰盖的最新热力学模型不能同时解释这些冰冻圈结构的观测形式，而用相同的各向异性增强的传统格伦流定律来描述它们的流变学。LGM Laurentide冰盖预计将随着轨道气候强迫而发展，与根据地表地貌和固体地球地球物理约束推断的纵横比相比，其厚度与水平范围的比率非常大。我们表明，如果用基于非常高质量的应力-应变-速率关系的实验室测量的新的流变学来代替Glen流定律表示的流变学，那么存在于LGM的现代格陵兰冰盖和Laurentide冰盖的纵横比可以被同时解释，而几乎不需要重新调整流动定律。
Abstract State-of-the-art thermomechanical models of the modern Greenland ice sheet and the ancient Laurentide ice sheet that covered Canada at the Last Glacial Maximum (LGM) are not able to explain simultaneously the observed forms of these cryospheric structures when the same, anisotropy-enhanced, version of the conventional Glen flow law is employed to describe their rheology. The LGM Laurentide ice sheet, predicted to develop in response to orbital climate forcing, is such that the ratio of its thickness to its horizontal extent is extremely large compared to the aspect ratio inferred on the basis of surface-geomorphological and solid-earth-geophysical constraints. We show that if the Glen flow law representation of the rheology is replaced with a new rheology based upon very high quality laboratory measurements of the stress-strain-rate relation then the aspect ratios of both the modern Greenland ice sheet and the Laurentide ice sheet, that existed at the LGM, are simultaneously explained with little or no retuning of the flow law.