Origin and de‐icing of multiple generations of ice‐cored moraines at Brúarjökull, Iceland

Schomacker, Anders; Kjær, Kurt H.

doi:10.1080/03009480701213554

Cited by 63 publications

(47 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Schomacker and Kjaer (2008) reported 0.9 m a -1 of mean annual surface lowering for the ice-cored moraines of Holmströmbreen in the period . Values of a similar magnitude were also presented for several Icelandic glaciers: 0.015-0.80 m a -1 for ice-cored moraines of Kvíárjökull (Bennett and Evans, 2012), 0.10-0.18 m a -1 for Brúarjökull (Schomacker and Kjaer, 2007), and 0.3-1.4 m a -1 for Kötlujökull (Krüger and Kjaer, 2000).…”

Section: Short-term Versus Long-term Dead-ice Meltingmentioning

confidence: 81%

“…Still, our knowledge about the quantitative aspect of the ice-cored moraines' degradation remains unsatisfactory (Schomacker, 2008). In many Arctic and mountain environments, ice-cored moraines constitute a significant proportion of the ice within the catchments (Schomacker and Kjaer, 2007;Schomacker, 2008). For example, in 2004, the volume of the dead-ice in the distal part of Holmströmbreen, Spitsbergen, was estimated by Schomacker and Kjaer (2008) to be 3.54 km 3 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

Ewertowski

Tomczyk

2015

Geomorphology

View full text Add to dashboard Cite

Extensive ice-cored moraine complexes are common elements, marking the last advance of many Svalbard glaciers. Sediment gravity flows are among the most dynamic processes, transforming these landforms. The short-term (yearly and weekly) dynamics of mass-wasting processes were studied in a cm-scale using repetitive topographic scanning. We monitored several active sites on the forelands of two glaciers, Ebbabreen and Ragnarbreen, both of which are located near the Petuniabukta at the northern end of Billefjorden in Spitsbergen.The surveys indicate high dynamic rates of landforms' transformation. The mean annual volume loss of sediments and dead-ice for the most active parts of the moraines was up to 1.8 m a -1 . However, most of the transformation occurred during summer, with the short-term values of mean elevation changes as high as −104 mm day −1 . In comparison, the dynamics of the other (i.e. non-active) parts of the ice-cored moraines were much lower, namely, the mean annual lowering (attributed mainly to dead-ice downwasting) was up to 0.3 m a -1 , whereas lowering during summer was up to 8 mm day −1 . Our results indicate that in the case of the studied glaciers, backwasting was much more effective than downwasting in terms of landscape transformation in the glacier forelands. However, despite the high activity of localised mass movement processes, the overall short-term dynamics of ice-cored moraines for the studied glaciers were relatively low. We suggest that as long as debris cover is sufficiently thick (thicker than the permafrost's active layer depths), the mass movement activity would occur only under specific topographic conditions and/or due to occurrence of external meltwater sources and slope undercutting. In other areas, ice-cored moraines remain a stable landsystem component in a yearly to decadal time-scale. Graphical abstractPlease cite this article as: Ewertowski, Marek W., Tomczyk, Aleksandra M., Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard, Geomorphology 234 (2015): 211-227,

show abstract

Section: Short-term Versus Long-term Dead-ice Meltingmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

Ewertowski

Tomczyk

2015

Geomorphology

View full text Add to dashboard Cite

show abstract

“…The spatial patterns and regional distributions of these ridge networks have more recently been employed by Evans et al ( , 2008Evans et al ( , 2014 to propose that they originate by the squeezing of subglacial till into basal crevasses formed during glacier surging, as identified on modern surging glaciers ( Fig. 2A; Sharp, 1985a, b;Rea, 1999, 2003;Evans et al, 2007;Schomacker and Kjaer, 2007).…”

Section: Characteristics Of Crevasse-squeeze Ridge (Csr) Corridorsmentioning

confidence: 99%

Crevasse-squeeze ridge corridors: Diagnostic features of late-stage palaeo-ice stream activity

2016

View full text Add to dashboard Cite

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. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

show abstract

“…Where glaciers have significant debris cover at their margins, they can sometimes lead to the formation of ice-cored moraines (Lukas, 2011). The cores of such deposits often continue to melt for decades to millennia after deposition (Carrara, 1975;Driscoll, 1980;Everest and Bradwell, 2003;Schomacker and Kjaer, 2007;Lüthgens et al, 2011). During this period, moraine surfaces are gradually lowered to a point where features may be difficult (or impossible) to identify (though the identification of such moraines might be promoted as thermokarst lakes develop on their surfaces -see section 4.2.3).…”

Section: Supply Of Debris To Glacier Marginsmentioning

confidence: 99%

A review of topographic controls on moraine distribution

2014

View full text Add to dashboard Cite

Ice-marginal moraines are often used to reconstruct the dimensions of former ice masses, which are then used as proxies for palaeoclimate. This approach relies on the assumption that the distribution of moraines in the modern landscape is an accurate reflection of former ice margin positions during climatically controlled periods of ice margin stability. However, the validity of this assumption is open to question, as a number of additional, nonclimatic factors are known to influence moraine distribution. This review considers the role played by topography in this process, with specific focus on moraine formation, preservation, and ease of identification (topoclimatic controls are not considered). Published literature indicates that the importance of topography in regulating moraine distribution varies spatially, temporally, and as a function of the ice mass type responsible for moraine deposition. In particular, in the case of ice sheets and ice caps ( > 1000 km 2 ), one potentially important topographic control on where in a landscape moraines are deposited is erosional feedback, whereby subglacial erosion causes ice masses to become less extensive over successive glacial cycles. For the marine-terminating outlets of such ice masses, fjord geometry also exerts a strong control on where moraines are deposited, promoting their deposition in proximity to valley narrowings, bends, bifurcations, where basins are shallow, and/or in the vicinity of topographic bumps. Moraines formed at the margins of ice sheets and ice caps are likely to be large and readily identifiable in the modern landscape. In the case of icefields and valley glaciers (10-1000 km 2 ), erosional feedback may well play some role in regulating where moraines are deposited, but other factors, including variations in accumulation area topography and the propensity for moraines to form at topographic pinning points, are also likely to be important. This is particularly relevant where land-terminating glaciers extend into piedmont zones (unconfined plains, adjacent to mountain ranges) where large and readily identifiable moraines can be deposited. In the case of cirque glaciers (< 10 km 2 ), erosional feedback is less important, but factors such as topographic controls on the accumulation of redistributed snow and ice and the availability of surface debris, regulate glacier dimensions and thereby determine where moraines are deposited. In such cases, moraines are likely to be small and particularly susceptible to post-depositional modification, sometimes making them difficult to identify in the modern landscape. Based on this review, we suggest that, despite often being difficult to identify, quantify, and mitigate, topographic controls on moraine distribution should be explicitly considered when reconstructing the dimensions of palaeoglaciers and that moraines should be judiciously chosen before being used as indirect proxies for palaeoclimate (i.e., palaeoclimatic inferences should only be drawn from moraines when topographic controls on mora...

show abstract

Origin and de‐icing of multiple generations of ice‐cored moraines at Brúarjökull, Iceland

Cited by 63 publications

References 53 publications

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard

Crevasse-squeeze ridge corridors: Diagnostic features of late-stage palaeo-ice stream activity

A review of topographic controls on moraine distribution

Contact Info

Product

Resources

About