Glaciohydrologic supercooling at Matanuska Glacier results in abundant and conspicuous summer ice growth even when air temperatures are constantly and significantly above freezing. Ice grows as frazil ice and anchor ice. Frazil ice grows unattached in high-velocity discharge water. Anchor ice grows at vent orifices, in subglacial conduits and canals, in moulins, and in fractures. Anchor ice can grow as large, debris-free platy crystals or, more commonly, as fine-grained, debris-rich laminated ice. To date, these types of summer ice growth have been reported at few glaciers and studied in detail at the Matanuska Glacier but we anticipate that glaciohydrologic supercooling and the associated ice growth are operating at numerous other glaciers with the appropriate geometries. The objective of this paper is to provide a photographic atlas, and brief explanation, of the ice growth forms and features observed at the Matanuska Glacier. We hope that it will enable other researchers to recognize the evidences of glaciohydrologic supercooling at additional glaciers and eventually establish glaciohydrologic supercooling, and the associated basal freeze-on, as a major debris entrainment and transportation mechanism.
|Number of pages
|Special Paper of the Geological Society of America
|Published - Jan 1 1999
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