posted on 2018-06-19, 10:12authored byD.J.A. Evans, Marek Ewertowski, Chris Orton, David GrahamDavid Graham
A surficial geology and geomorphology map of the forelands of the Sandfellsjökull and Oldufellsjökull piedmont lobes of the east Mýrdalsjökull ice cap is used to characterise the historical and modern landscape imprint in a glacial landsystems context. This serves as a modern analogue
for palaeoglaciological reconstructions of ice cap systems that operated outlet lobes of contrasting dynamics, but the subtle variability in process-form regimes is encoded in the geomorphology. The landsystems of the two piedmont lobes reflect significantly different process-form regimes, and hence contrasting historical glacier dynamics, despite the fact that they are nourished by the
same ice cap. The Sandfellsjökull landsystem displays the diagnostic criteria for active temperate glacier operation, including arcuate assemblages of inset minor push moraines and associated flutings, kame terrace and ice-dammed lake deposits, linear sandar directed by overridden moraine arcs, and since 1945, features, such as ice-cored, pitted, and glacially pushed outwash fans that are linked to englacial esker networks representative of recession into an overdeepening. Moraine plan forms have also changed from weakly crenulated and discontinuous curvilinear ridges to
sawtooth features and crevasse-squeeze ridges and till eskers in response to changing proglacial drainage conditions. The Oldufellsjökull landsystem displays subtle signatures of jökulhlaup-driven
surges, including sparse and widely spaced moraine clusters that are separated by exceptionally long flutings. The subtlety of the surge imprint at Oldufellsjökull was recognised only by comparison with
nearby Sandfellsjökull, suggesting that palaeo-surging has likely been under-estimated in the ancient landform record. Hence, the simple imprint of sparse and widely spaced moraine clusters that are
separated by exceptionally long flutings should be included as possible surge-diagnostic criteria.
Funding
This research was funded by the Royal Geographical Society, the Carnegie Trust and the Royal Scottish Geographical Society and the Marie Curie Intra European Fellowship (Grant no. 299130).
History
School
Social Sciences
Department
Geography and Environment
Published in
Geosciences
Volume
8
Issue
6
Citation
EVANS, D.J.A. ... et al., 2018. The glacial geomorphology of the ice cap Piedmont Lobe landsystem of East Myrdalsjokull, Iceland. Geosciences, 8(6): 194.
This work is made available according to the conditions of the Creative Commons Attribution 4.0 Unported (CC BY 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/
Acceptance date
2018-05-28
Publication date
2018-05-30
Notes
This is an Open Access Article. It is published by MDPI under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/