Skaftafellsjökull, Iceland: glacial geomorphology recording glacier recession since the Little Ice Age

Abstract

Citation for published item:ivnsD hvid tF eF nd iwertowskiD wrek nd yrtonD ghris @PHIUA 9kftfellsj¤ okullD selnd X glil geomorphology reording glier reession sine the vittle se egeF9D tournl of mpsFD IQ @PAF ppF QSVEQTVF Further information on publisher's website: Use policyThe 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. A 1:5700 scale map of the recently deglaciated foreland of Skaftafellsjökull, Iceland as it appeared in 2007, depicts a typical active temperate glacial landsystem with a clear pattern of sequentially changing push moraine morphologies, including remarkable hairpin-shaped moraines, indicative of spatial and temporal variability in process-form regimes in glacier sub-marginal settings. Similar to other Icelandic glacier forelands, this demonstrates that the piedmont glacier lobes of the region have developed strong longitudinal crevassing and well-developed ice-marginal pecten during their historical recession from the Little Ice Age 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. ARTICLE HISTORY

Sub-annual moraine formation at an active temperate Icelandic glacier

“…The process-form regime responsible for the formation of the push/squeeze moraines at Fjallsjökull, along with the associated crevasse-squeeze ridges, is comparable to that observed at other Icelandic active temperate outlet glaciers (e.g. Sharp, 1984;Evans and Hiemstra, 2005;Chandler et al, 2016a;Evans et al, 2016aEvans et al, , 2017Evans and Ewertowski, 2018;Evans et al, 2018c). Our sedimentological data are also in general agreement with seminal work by Price (1970), who proposed that squeezing of water-soaked tills from beneath the glacier margin was responsible for moraine formation at Fjallsjökull.…”

“…We therefore interpret LF 1 as a subglacial traction till, as in other ice-marginal/annual moraines elsewhere in Iceland (e.g. Sharp, 1984;Bradwell, 2004a;Evans and Hiemstra, 2005;Chandler et al, 2016a;Evans et al, 2017Evans et al, , 2018a. The loose character of the upper diamictic facies (LF 2), its internal stratification and its conformity with the lower contact and moraine surface slope are consistent with a glaciogenic debris flow deposit (cf.…”

“…As noted above, the combination of ice-marginal squeezing and pushing, together with submarginal freeze-on in some situations, has been widely recognized as contributing to minor/annual moraine formation at Icelandic outlet glaciers (cf. Sharp, 1984;Boulton, 1986;Evans and Hiemstra, 2005;Chandler et al, 2016a;Evans et al, 2016aEvans et al, , 2017. However, the operation of these submarginal and ice-marginal processes over a single seasonal cycle is usually linked to the construction of a single submarginal till wedge and push/squeeze moraine per year (cf.…”

“…Annual moraines are particularly prevalent in Iceland, and long sequences of (presumed) annual moraines are ubiquitous on the low-lying forelands of the maritime outlets of Öraefajökull and Vatnajökull, southeast Iceland (e.g. Thórarinsson, 1967;Price, 1970;Sharp, 1984;Boulton, 1986;Evans and Twigg, 2002;Evans and Hiemstra, 2005;Chandler et al, 2016aChandler et al, , 2016bChandler et al, , 2016Evans et al, 2016aEvans et al, , 2017Evans et al, , 2019a. With their distinctive, intricate 'sawtooth' or crenulated planforms, these annual moraine sequences are spectacular phenomena and a characteristic signature of the active temperate glacial landsystem (cf.…”

The glacial landsystem of a tropical glacier: Charquini Sur, Bolivian Andes

“…The boulder walls within M8, M9 and MA are also consistent with minor frontal re-advances into a boulder field and the bulldozing of small ridges. Flutings are visible between the MB ridges, similar to the landform pattern observed at active temperate glacier margins in Iceland (Evans and Twigg, 2002;Evans, 2003b;Chandler et al, 2016aChandler et al, , 2016bEvans et al, 2016aEvans et al, , 2016bEvans et al, , 2017. The presence of annual moraines suggests that, up to 2005 at least, Charquini Sur had a seasonally-oscillating active margin.…”