Geophysical Studies of the Lateral Transition Zone of an Active Antarctic Ice Stream

活跃南极冰流横向过渡带的地球物理研究

• 批准号: 9220678
• 负责人: Charles Bentley
• 金额: $ 36.57万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-05-01 至 1996-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9220678&HistoricalAwards=false
• 关键词: Geophysical; Studies; Lateral; Transition; Zone

The manner and rate of deformation of the Earth's major ice sheets depend on a complex interplay of their geographical and climatic setting, as well as their internal dynamics. In the West Antarctic Ice Sheet, it is known that rapidly moving ice streams alternate with large areas of stagnant ice, and that the transition between streaming and non-streaming flow can be be quite narrow. In these lateral shear margins it is thought that the physical controls on ice stream dynamics must show significant differences. This study will examine the geophysical differences between an ice stream and a stagnant ridge along the Siple Coast in West Antarctica. The ice will be probed with electromagnetic and seismic waves to infer the internal temperature and the crystalline structure of the ice, as well as the proportion of old (Wisconsin Ice Age) ice, since it is known that ice flow laws depend exponentially on temperature, that ice crystals are much less resistant to deformation in the plane of their hexagonal faces than in other directions, and that old ice may deform much more readily than ice of more recent geological age. Measurement of radar diffraction patterns and the analysis of the records of micro- earthquakes can be used to show whether the base of the ice sheet is frozen to the underlying bedrock.

地球主要冰的变形方式和速率 表取决于其地理和地理位置的复杂相互作用， 气候环境，以及它们的内部动态。 在西方 南极冰盖，众所周知，快速移动的冰流 与大面积的停滞冰交替， 流和非流之间的距离可能相当窄。 在这些横向剪切边缘， 对冰流动力学的控制必须显示出显著的差异。 这项研究将探讨地球物理的差异， 西海岸西海岸沿着有冰流和停滞的山脊 南极洲 冰将被电磁探测， 地震波来推断内部温度和晶体 冰的结构，以及旧的比例（威斯康星州 冰河时代）冰，因为它是已知的，冰流动规律取决于 温度呈指数变化， 在它们的六边形面的平面中比在它们的六边形面的平面中更能抵抗变形， 在其他方向，旧的冰可能更容易变形 比地质年代更近的冰要多。 雷达测量 衍射图样和显微记录的分析 地震可以用来显示冰盖的底部 都被冻在了下面的基岩上