eCite Digital Repository

Dilatant till facilitates ice-stream flow in northeast Greenland

Citation

Christianson, K and Peters, LE and Alley, RB and Anandakrishnan, S and Jacobel, RW and Riverman, KL and Muto, A and Keisling, BA, Dilatant till facilitates ice-stream flow in northeast Greenland, Earth and Planetary Science Letters, 401 pp. 57-69. ISSN 0012-821X (2014) [Refereed Article]

Copyright Statement

Copyright 2014 Elsevier B.V

DOI: doi:10.1016/j.epsl.2014.05.060

Abstract

We present radio-echo sounding (RES), global positioning system (GPS), and active-source seismic data across the central portion of the Northeast Greenland Ice Stream (NEGIS). NEGIS widens downglacier from a small region of high geothermal flux near the ice divide. Our data reveal high-porosity (40+%) water-saturated till lubricating the ice stream. Ice accelerates and thins as it flows into NEGIS, producing marginal troughs in surface topography. These troughs create steep gradients in the subglacial hydropotential that generate parallel "sticky" and "slippery" bands beneath the shear margins. The low-porosity "sticky" sediment bands limit ice entrainment across the margins and thus restrict further widening, producing the long, narrow, and relatively stable ice stream. However, the observed relations among surface elevation, basal water routing, broad sedimentary drape, and till dilatancy suggest that rapid shifts in ice dynamics are possible, including rapid transmission of ocean forcing inland. The source and routing of the subglacial till are unclear, but our data help constrain hypotheses.

Item Details

Item Type:Refereed Article
Keywords:ice dynamics, subglacial environment, radio glaciology, seismology
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Glaciology
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
Author:Peters, LE (Dr Leo Peters)
ID Code:103750
Year Published:2014
Web of Science® Times Cited:21
Deposited By:IMAS Research and Education Centre
Deposited On:2015-10-27
Last Modified:2017-10-30
Downloads:0

Repository Staff Only: item control page