Fireweed Rock Glacier: Geophysical Survey and Flow Modeling

火草岩冰川：地球物理调查和流动模拟

• 批准号: 9806648
• 负责人: Keith Echelmeyer
• 金额: $ 11.57万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9806648&HistoricalAwards=false
• 关键词: Fireweed; Rock; Glacier; Geophysical; Survey

Rock glaciers are the largest and most pronounced mountain permafrost landforms. Recently, scientific interest in rock glaciers has dramatically increased due to the geotechnical problems and natural hazards they pose, their potential for archiving past and present geologic conditions in alpine environments, their significance in the hydrologic cycle, and their role as a debris transport mechanism. Knowledge of rock glaciers' internal composition and rheology is important for addressing these topics. Our understanding of internal structures of rock glaciers is often speculative because rock glaciers are difficult to inspect internally. This is a unique opportunity to document the internal composition and structure in a complete transverse cross-section through the Fireweed Rock Glacier, Wrangell Mountains, Alaska because the entire snout was recently catastrophically calved. This rock glacier consists of a debris-covered m(lange. The ice matrix, which accounts for about one-half of the ice-rock, displays prominent flow signatures. The Fireweed Rock Glacier is also unique in that it has a high flow rate. The Principal Investigator will take advantage of this unique opportunity to investigate the structure and flow mechanics of the Fireweed Rock Glacier. The first objective will be to perform a complete geophysical survey of the glacier. Geophysical techniques will be calibrated using known geometry and structure at the exposed terminus section, and then extend up glacier to provide a detailed picture of the internal structure and geometry. The second objective will be to develop a numerical model of rock glacier flow by analyzing velocity measurements and the geometry determined by the geophysical survey. The results should significantly improve the application of geophysical survey techniques to rock glaciers and mountain permafrost and lead to a better understanding of the rheological laws for the ice-rock mixtures that compose rock glaciers and frozen ground.

岩石冰川是最大和最明显的山地永久冻土地貌。 最近，科学界对岩石冰川的兴趣急剧增加，这是由于岩石冰川带来的岩土工程问题和自然灾害，它们在高山环境中存档过去和现在地质条件的潜力，它们在水文循环中的重要性，以及它们作为碎片运输机制的作用。 了解岩石冰川的内部成分和流变学对于解决这些问题很重要。 我们对岩石冰川内部结构的理解往往是推测性的，因为岩石冰川内部很难检查。 这是一个独特的机会，通过一个完整的横截面记录的内部组成和结构，通过火草岩冰川，兰格尔山脉，阿拉斯加，因为整个鼻子最近灾难性地崩解。 这个岩石冰川由一个被碎屑覆盖的m（lange。 约占冰岩一半的冰基质显示出显著的流动特征。 火草岩冰川的独特之处还在于它具有高流速。 首席研究员将利用这一独特的机会，调查火草岩冰川的结构和流动力学。 第一个目标是对冰川进行全面的地球物理调查。 地球物理技术将使用已知的几何形状和结构在暴露的终端部分进行校准，然后延伸到冰川，以提供内部结构和几何形状的详细图片。 第二个目标是通过分析速度测量和地球物理调查确定的几何形状，建立岩石冰川流动的数值模型。 这些结果将大大改善地球物理调查技术在岩石冰川和山地永久冻土中的应用，并有助于更好地了解构成岩石冰川和冻土的冰岩混合物的流变学规律。