ARCUS | Arctic Research Consortium of the United States

6th Annual ARCUS Award for Arctic Research Excellence


Submitted by   Matthew J. Roberts
Authors   Matthew J. Roberts, F.S. Tweed, A.J. Russell, Ó. Knudsen, D.E. Lawson, G.J. Larson, E.B. Evenson, and H. Björnsson
Category   Physical Science
Title   Glaciohydraulic supercooling in Iceland
Affiliation   Department of Geography, Staffordshire University, Staffordshire, UK

Abstract

We present evidence of glaciohydraulic supercooling under jökulhlaup and ablationdominated conditions from two temperate Icelandic glaciers. Observations show that freezing of sediment-laden meltwater leads to intraglacial debris entrainment during normal and extreme hydrological regimes. Intraglacial frazil ice propagation under normal ablationdominated conditions can trap copious volumes of sediment, which forms anomalously thick outcrops of debris-rich ice. Glaciohydraulic supercooling plays an important role in intraglacial debris entrainment and should be given more attention in models of basal ice development. Extreme jökulhlaup conditions can result in significant intraglacial sediment accretion by supercooling, which may explain the concentration of englacial sediments deposited in Heinrich layers in the North Atlantic during the last glaciation.