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Equifinality and preservation potential of complex eskers

Storrar, Robert D.; Ewertowski, Marek; Tomczyk, Aleksandra M.; Barr, Iestyn D.; Livingstone, Stephen J.; Ruffell, Alastair; Stoker, Ben J.; Evans, David J.A.

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Robert D. Storrar

Marek Ewertowski

Aleksandra M. Tomczyk

Iestyn D. Barr

Stephen J. Livingstone

Alastair Ruffell

Ben J. Stoker


Eskers are useful for reconstructing meltwater drainage systems of glaciers and ice sheets. However, our process understanding of eskers suffers from a disconnect between sporadic detailed morpho‐sedimentary investigations of abundant large‐scale ancient esker systems, and a small number of modern analogues where esker formation has been observed. This paper presents the results of detailed field and high‐resolution remote sensing studies into two esker systems that have recently emerged at Hørbyebreen, Svalbard, and one at Breiðamerkurjökull, Iceland. Despite the different glaciological settings (polythermal valley glacier vs. active temperate piedmont lobe), in all cases a distinctive planform morphology has developed, where ridges are orientated in two dominant directions corresponding to the direction of ice flow and the shape of the ice margin. These two orientations in combination form a cross‐cutting and locally rectilinear pattern. One set of ridges at Hørbyebreen is a hybrid of eskers and geometric ridges formed during a surge and/or jökulhlaup event. The other sets of ridges are eskers formed time‐transgressively at a retreating ice margin. The similar morphology of esker complexes formed in different ways on both glacier forelands implies equifinality, meaning that care should be taken when interpreting Quaternary esker patterns. The eskers at Hørbyebreen contain substantial ice‐cores with a high ice:sediment ratio, suggesting that they would be unlikely to survive after ice melt. The Breiðamerkurjökull eskers emerged from terrain characterized by buried ice that has melted out. Our observations lead us to conclude that eskers may reflect a wide range of processes at dynamic ice margins, including significant paraglacial adjustments. This work, as well as previous studies, confirms that constraints on esker morphology include: topographic setting (e.g. confined valley or broad plain); sediment and meltwater availability (including surges and jökulhlaups); position of formation (supraglacial, englacial or subglacial); and ice‐marginal dynamics such as channel abandonment, the formation of outwash heads or the burial and/or exhumation of dead ice.


Storrar, R. D., Ewertowski, M., Tomczyk, A. M., Barr, I. D., Livingstone, S. J., Ruffell, A., …Evans, D. J. (2020). Equifinality and preservation potential of complex eskers. Boreas: An International Journal of Quaternary Research, 49(1), 211-231.

Journal Article Type Article
Acceptance Date Aug 30, 2019
Online Publication Date Oct 14, 2019
Publication Date Jan 31, 2020
Deposit Date Oct 15, 2019
Publicly Available Date Oct 14, 2020
Journal Boreas
Print ISSN 0300-9483
Electronic ISSN 1502-3885
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 49
Issue 1
Pages 211-231


Accepted Journal Article (5 Mb)

Copyright Statement
This is the accepted version of the following article: Storrar, Robert D., Ewertowski, Marek, Tomczyk, Aleksandra M., Barr, Iestyn D., Livingstone, Stephen J., Ruffell, Alastair, Stoker, Ben J. & Evans, David J. A. (2020). Equifinality and preservation potential of complex eskers. Boreas 49(1): 211-231, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.

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