Frost Mounds Formed by Degradation at Slope Mountain, Alaska, U.S.A.

Abstract

Stable, ice-cored frost mounds can form by differential ablation of seasonally developed massive ground ice. Although degradation frost mounds have no diagnostic mound morphology, these features can be identified by observing formative processes in the field and by examination of the mound core. Several field techniques were employed on massive ice-cored mounds which developed in a marsh near Slope Mountain, Alaska. Stratigraphic relationships within the mound core, ice petrofabrics, and ionic concentration patterns of ice crystals as they vary with core depth were correlated to the mound-forming processes, and indicate that these landforms are stable remnants of a sill-like massive ground ice plateau which has been differentially eroded by stream action. In addition, the core data and field observation can be used to infer the processes associated with massive ground-ice formation. It appears that a 1-m-thick, massive ice plateau develops in the marsh each winter due to the concordant injection and freez...