Debris transport by Loch Lomond Readvance glaciers in Northern Scotland: Basin form and the within‐valley asymmetry of lateral moraines

Benn, Douglas I.

doi:10.1002/jqs.3390040305

Cited by 57 publications

(42 citation statements)

References 39 publications

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“…A similar frozen margin is presently constructing discontinuous debris bands along the glacier snout. The clast form data for both Fremri-and InnriHagajökull reveal lateral moraine asymmetry (Benn, 1989), consistent with the contrasting expanses of steep bedrock slopes above the glacier surfaces.…”

Section: Discussionmentioning

confidence: 77%

Controlled moraine development and debris transport pathways in polythermal plateau icefields: examples from Tungnafellsjökull, Iceland

Evans

2010

Earth Surf Processes Landf

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A modern landsystems analogue for plateau icefi eld glaciation is presented, based upon Tungnafellsjökull in the arid, cold interior of Iceland. Landform mapping and intensive clast form analysis on three separate forelands occupied during the Little Ice Age reveal variability in the morphology of moraines and the degree of clast modifi cation, which is interpreted as a function of the complex interplay between: (a) the effi cacy of glacial erosion; (b) passive versus active debris transfer mechanisms; and (c) the volume of debris provision for ice-marginal freeze-on mechanisms. A steep outlet bounded by rockwalls produced a landform assemblage and debris transport signature typical of valley glaciers, whereas two unconfi ned outlets produced a landform-sediment imprint typical of polythermal conditions. This comprises subglacial bedforms, relating to the initiation of warm-based ice by strain heating below icefalls at the plateau edge, terminating at arcs of ice-cored (controlled) moraine representative of frozen snout conditions. Patterns in clast form data on the unrestricted forelands refl ect the characteristics of glacier dynamics and thermal regimes at the margin of a plateau icefi eld, where bedrock steps of suffi cient size to initiate strain heating and bedrock abrasion and plucking are located only a short distance from the marginal freeze-on conditions of a snout creating debris-rich folia and controlled moraine. Additional englacial debris may well have been carried to the glacier margin through the development of ogives and englacial thrusting at the base of the icefall, thereby explaining the occurrence of striae on clasts that have otherwise been little modifi ed by glacial abrasion.

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Section: Discussionmentioning

confidence: 77%

Controlled moraine development and debris transport pathways in polythermal plateau icefields: examples from Tungnafellsjökull, Iceland

Evans

2010

Earth Surf Processes Landf

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“…Because the formation conditions of debris covered glaciers are affected by topographic variables such as aspect (Benn, 1989;Nagai et al, 2013) and steepness (Scherler et al, 2011), we examined the relationships between debris thickness and slope aspect and steepness in each RGI region. Because the debris-covered area was small, and it was difficult to investigate its geographical distribution, we excluded Iceland and Svalbard from the analysis.…”

Section: Geographical Characteristics Of Debris Distributionmentioning

confidence: 99%

A global high-resolution map of debris on glaciers derived from multi-temporal ASTER images

Sasaki

Noguchi

Zhang

et al. 2016

Preprint

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Abstract. Supraglacial debris affects the response of glaciers to climate change by altering the reflectivity of solar radiation and conductive heat flux. To accurately assess the contribution of glacier melts to sea level rise, water resources and natural 10 hazards, it is important to account for the effects of debris. However, due to the practical difficulties of global-scale field measurements, information regarding the spatial distribution of the thickness and thermal properties of debris on glaciers is limited; hence, the effects of debris on glacier melting are not explicitly taken into account in current global glacier models. In this study, we developed a dataset of the thermal resistance of debris on glaciers at 90-m resolution derived from multi-temporal satellite images and satellite-derived radiation data at the global scale, excluding Greenland, Antarctica, and some of the Arctic. 15We found that supraglacial debris covered 16.8% of the entire analyzed glacial area. The highest debris cover percentage occurred in New Zealand, and the lowest was in Iceland. The area of thick debris (which suppresses glacier melting) was about two times that of thin debris (which accelerates glacier melting), indicating that the insulation effect of debris to inhibit glacier melting may dominate at the global scale. The distribution of debris was also related to the slope aspect of glaciers. Despite the limitations of this study, the resulting global distribution of the thermal resistance of debris can be incorporated into global 20 glacier models, and hence it provides a solid basis for evaluating the effects of debris on glacial melting.

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“…The two large moraines in Srath Tarabhan are not symmetrical across the valley either, being significantly better developed on the northern side of the glen. Although moraine asymmetry of valley glaciers may be accounted for by differential debris input from valleyside rockwalls (Benn 1989), this does not seem likely for either Srath Tarabhan or Glen Lyon, considering that exposed rock faces exist on both sides of both these valleys. Many valleys show no morainic landforms at all, while in contrast the northwestern flanks of Beinn an Dothaidh and Beinn Achaladair are dominated by such features.…”

Section: Deglaciationmentioning

confidence: 99%

Evaluating Younger Dryas glacier reconstructions in part of the western Scottish Highlands: a combined empirical and theoretical approach

Golledge

Hubbard²

2005

Boreas

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2005 (August): Evaluating Younger Dryas glacier reconstructions in part of the western Scottish Highlands: a combined empirical and theoretical approach. Boreas, Vol. 34, pp. 274-286. Oslo. ISSN 0300-9483.Current understanding of the Younger Dryas (Loch Lomond Stadial) ice cap in Scotland is dominated by reconstructions derived solely from field evidence. We use an area in the western Scottish Highlands to evaluate three examples of this approach by comparing the proposed glacier reconstructions with new empirical data and the predictions of a high-resolution numerical model. Particular emphasis is placed on accurately determining the maximum surface altitude attained by the ice cap, dominant palaeo-iceflow directions and the style of ice-cap recession. By combining new geomorphological and sedimentological data with model predictions, we present a revised interpretation of the build-up and decay of Loch Lomond Stadial ice in the study area -one that suggests a maximum ice-surface altitude of c. 900 m a.s.l., east and southeastward iceflow and active recession of a dynamic margin. Good agreement between the new field-based interpretation and the predictions of the numerical model validates the latter and by implication extends confidence in its veracity beyond the study area.

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Debris transport by Loch Lomond Readvance glaciers in Northern Scotland: Basin form and the within‐valley asymmetry of lateral moraines

Cited by 57 publications

References 39 publications

Controlled moraine development and debris transport pathways in polythermal plateau icefields: examples from Tungnafellsjökull, Iceland

Controlled moraine development and debris transport pathways in polythermal plateau icefields: examples from Tungnafellsjökull, Iceland

A global high-resolution map of debris on glaciers derived from multi-temporal ASTER images

Evaluating Younger Dryas glacier reconstructions in part of the western Scottish Highlands: a combined empirical and theoretical approach

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