A Laboratory Study of Texture Development During Grain Size Sensitive Creep of Ice, with Applications to the Flow of Glaciers and Ice Sheets

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This award supports a project to conduct laboratory experiments to investigate textures formed in ice during superplastic flow. Superplastic flow has recently been discovered in the laboratory and can be considered a new flow mechanism for ice. A simple extrapolation of these new data for superplastic flow from laboratory to natural conditions suggests that glaciers and ice sheets flow via this mechanism. Furthermore, several grain-scale features in ice (e.g., crystal shape) produced during superplastic flow in the laboratory are remarkably similar to those observed in glaciers and ice sheets. Despite this exciting discovery, however, important questions remain before we can apply with full confidence these new flow data in mathematical models of glacier and ice sheet flow. The textures seen in laboratory studies will be compared with those observed in field studies of glaciers and ice sheets. These comparisons, coupled with comparisons of the new superplastic flow data from the laboratory with flow measurements from field studies, will provide a powerful method for further assessing the importance of superplastic flow in nature and thereby improve our understanding of glacier and ice sheet dynamics and global climate change. Experiments will be conducted by the PI and an undergraduate research assistant. Experimental results will be published in relevant refereed journals, presented at glaciology meetings and incorporated into coursework.