Basal conditions and ice dynamics inferred from radar-derived internal stratigraphy of the northeast Greenland ice stream

We analyze the internal stratigraphy in radio-echo sounding data of the northeastGreenland ice stream to infer past and present ice dynamics. In the upper reaches of the ice stream, wepropose that shear-margin steady-state folds in internal reflecting horizons (IRHs) form due to theinfluence of ice...

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Bibliographic Details
Published in:Annals of Glaciology
Main Authors: Keisling, BA, Christianson, K, Alley, RB, Peters, LE, Christian, JEM, Anandakrishnan, S, Riverman, KL, Muto, A, Jacobel, RW
Format: Article in Journal/Newspaper
Language:English
Published: Int Glaciol Soc 2014
Subjects:
Earth Sciences
Physical Geography and Environmental Geoscience
Glaciology
Greenland
Annals of Glaciology
Online Access:https://doi.org/10.3189/2014AoG67A090
http://ecite.utas.edu.au/103753
Description
Summary:We analyze the internal stratigraphy in radio-echo sounding data of the northeastGreenland ice stream to infer past and present ice dynamics. In the upper reaches of the ice stream, wepropose that shear-margin steady-state folds in internal reflecting horizons (IRHs) form due to theinfluence of ice flow over spatially varying basal lubrication. IRHs are generally lower in the ice streamthan outside, likely because of greater basal melting in the ice stream from enhanced geothermal fluxand heat of sliding. Strain-rate modeling of IRHs deposited during the Holocene indicates no recentmajor changes in ice-stream vigor or extent in this region. Downstream of our survey, IRHs are disruptedas the ice flows into a prominent overdeepening. When combined with additional data from otherstudies, these data suggest that upstream portions of the ice stream are controlled by variations in basallubrication whereas downstream portions are confined by basal topography.

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