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Glacial Geomorphology Recording Glacier Recession Since the Little Ice Age.', Journal of Maps., 13 (2)

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Glacial Geomorphology Recording Glacier Recession Since the Little Ice Age.', Journal of Maps., 13 (2) Durham Research Online Deposited in DRO: 02 May 2017 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Evans, David J. A. and Ewertowski, Marek and Orton, Chris (2017) 'Skaftafellsj¤okull,Iceland : glacial geomorphology recording glacier recession since the Little Ice Age.', Journal of maps., 13 (2). pp. 358-368. Further information on publisher's website: https://doi.org/10.1080/17445647.2017.1310676 Publisher's copyright statement: c 2017 The Author(s). Published by Informa UK Limited, trading as Taylor Francis Group on behalf of Journal of Maps This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk Journal of Maps ISSN: (Print) 1744-5647 (Online) Journal homepage: http://www.tandfonline.com/loi/tjom20 Skaftafellsjökull, Iceland: glacial geomorphology recording glacier recession since the Little Ice Age David J. A. Evans, Marek Ewertowski & Chris Orton To cite this article: David J. A. Evans, Marek Ewertowski & Chris Orton (2017) Skaftafellsjökull, Iceland: glacial geomorphology recording glacier recession since the Little Ice Age, Journal of Maps, 13:2, 358-368, DOI: 10.1080/17445647.2017.1310676 To link to this article: http://dx.doi.org/10.1080/17445647.2017.1310676 © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps View supplementary material Published online: 27 Apr 2017. Submit your article to this journal Article views: 18 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tjom20 Download by: [Durham University Library] Date: 02 May 2017, At: 07:13 JOURNAL OF MAPS, 2017 VOL. 13, NO. 2, 358–368 http://dx.doi.org/10.1080/17445647.2017.1310676 SCIENCE Skaftafellsjökull, Iceland: glacial geomorphology recording glacier recession since the Little Ice Age David J. A. Evansa, Marek Ewertowski b and Chris Ortona aDepartment of Geography, Durham University, Durham, UK; bFaculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznan, Poland ABSTRACT ARTICLE HISTORY A 1:5700 scale map of the recently deglaciated foreland of Skaftafellsjökull, Iceland as it Received 5 August 2016 appeared in 2007, depicts a typical active temperate glacial landsystem with a clear pattern Revised 20 March 2017 of sequentially changing push moraine morphologies, including remarkable hairpin-shaped Accepted 21 March 2017 moraines, indicative of spatial and temporal variability in process-form regimes in glacier KEYWORDS sub-marginal settings. Similar to other Icelandic glacier forelands, this demonstrates that the Active temperate glacial piedmont glacier lobes of the region have developed strong longitudinal crevassing and landsystem; Skaftafellsjökull; well-developed ice-marginal pecten during their historical recession from the Little Ice Age push moraines maximum moraines, likely driven by extending ice flow and poorly drained sub-marginal conditions typical of the uncovering of overdeepenings. Additionally, the localized development of a linear tract of kame and kettle topography is interpreted as the geomorphic and sedimentary signature of thrust stacked and gradually melting debris-rich glacier ice, a feature hitherto unrecognized in the Icelandic active temperate lobe landsystem signature. 1. Introduction future if ice recession continues at its present rate (cf. Bennett, Evans, Carbonneau, & Twigg, 2010; Chandler The aim of the mapping project presented here was to et al., 2015, 2016; Evans et al., 2015; Phillips, Finlayson, assess, at the scale of 1:5700 (Main Map), the spatial Bradwell, Everest, & Jones, 2014; Phillips, Finlayson, & distribution of post-Little Ice Age glacial sediment– Jones, 2013). landform associations on the Skaftafellsjökull foreland (Figure 1), southern Iceland and to thereby test the hypothesis that the active temperate piedmont lobes 2. Methods of map production of the southern Vatnajökull and Öræfajökull ice caps have produced similar landsystem signatures that The Skaftafellsjökull snout and its foreland were record temporally changing, climatically and topogra- mapped using colour aerial photographs taken by the phically controlled glacial process-form regimes (cf. Airborne Research and Survey Facility (ARSF) of the Chandler, Evans, & Roberts, 2016; Chandler, Evans, Natural Environment Research Council UK in 2007. Roberts, Ewertowski, & Clayton, 2015; Evans & Coordinates for ground control points (GCP) were col- Orton, 2014; Evans, Ewertowski, & Orton, 2015; Jóns- lected in September 2013 using dGPS over the glacier son et al., 2016). More specifically, the occurrence on foreland (27 points) and on the surrounding hill sum- these glacier forelands of widespread sawtooth mor- mits (24 points). Twenty-six points were used as GCP aines with unusually long limbs/crevasse infills (Figure to establish absolute orientation for the generation of 1; Evans et al., 2015; Evans, Nelson, & Webb, 2010; an orthophotograph and digital elevation model Price, 1970) has been linked to the intensive develop- (DEM). Internal error for this GCP in 3D space was ment of longitudinal crevassing in lobate snouts, oper- 0.73 m (x-error = 0.23 m; y-error = 0.29 m, z-error = ating only over the most recent decades of ice recession 0.63 m). A further 25 points were utilized as indepen- and hence apparently linked to extending ice flow and dent checkpoints to assess the errors. The error in 3D poorly drained sub-marginal conditions. Such con- space based on these 23 checkpoints was 0.85 m (x- ditions appear to have prevailed since recession into error = 0.32; y-error = 0.46 m; z-error = 0.65 m). A prominent overdeepenings (Cook & Swift, 2012) total of four photographs were orthorectified and located behind overridden moraine arcs and are there- mosaicked using Agisoft Photoscan Professional Edi- fore likely to dominate for several decades into the tion. Mapping was then undertaken on a coloured CONTACT David J. A. Evans [email protected] Department of Geography, Durham University, South Road, Durham DH1 3LE, UK © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. JOURNAL OF MAPS 359 Figure 1. Aerial view of the Skaftafellsjökull snout and foreland in 2012 showing the more recent push moraines and their sawtooth planform and localized superimposition. The superimposition of numerous moraines dating from the 1960s through the 1990s and culminating in the early mid-1990s readvance, are visible in the middle of the image. Also well illustrated in this view is the radial crevassing and pecten of the glacier margin. ink film overlain on the orthophotograph and involved limits at around 1870–1890 AD, although the 1960s– the simultaneous interpretation of surface materials 1990s were decades of slower recession, with some gla- and landforms based on ground truth fieldwork in ciers undergoing significant readvances (Figure 2; the summers of 2012–2014 and the desk top viewing Boulton, 1986; Bradwell, Sigurðsson, & Everest, 2013; of stereoscopic images. The orthophotograph proces- Hannesdóttir, Björnsson, Pálsson, Aðalgeirsdóttir, & sing and contour generation were both performed in Guðmundsson, 2015). Overall, the active temperate ESRI ArcGIS. Contours were overlain on the surficial nature of these glaciers (cf. Evans & Twigg, 2002)is geology and geomorphology and are spaced differently manifest in short annual readvances during overall according to the general topography so that the more recession in response to the winter period of reduced subdued terrain of the glacier foreland was contour ablation, giving rise to the emplacement of inset spaced at 5-m intervals below 200 m a.s.l. and the sequences of push moraines (Boulton, 1986; Chandler higher relief mountain sides at the lateral margins of et al., 2015, 2016). In terms of general recession, Icelan- the glacier at 20 m intervals above 200 m a.s.l. The dic glaciers are thought to be particularly sensitive to mountain sides are depicted by the orthophotograph inter-annual variations in summer average air temp- image and have not been mapped, as they contain no eratures to which they have a very rapid response glacial deposits but comprise instead bedrock outcrops
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