Supercooled meltwater discharge from Skeiðarárjökull and Skaftafellsjökull and associated glacial debris entrainment

Introduction Glaciers and ice sheets entrain large quantities of sediment and processes by which they do so continue to be debated. Knowledge of glacial sediment entrainment processes is crucial to understanding past and present sediment fluxes and the sedimentary record. Glaciohydraulic supercooling has been identified as an active sediment entrainment mechanism at glaciers in Alaska(e.g. Lawson et al., 1998; Evenson et al., 1999) and was subsequently documented at several temperate Icelandic glaciers (e.g. Roberts et al., 2002; Tweed et al., 2005; Cook et al., 2007, 2010;Larson et al., 2010). It has also been suggested that that rapid discharge of supercooled meltwaterfrom the base of over-deepened ice sheet basins during the Quaternary constitutes a plausible mechanism for entraining extensive amounts of sediment in the Laurentide Ice Sheet (Alley et al.,1998, 1999; Roberts et al., 2002; Larson et al., 2006). There has been a tendency for the process tobe uncritically accepted and the controls on the spatial and temporal variability of glaciohydraulic supercooling have yet to be thoroughly investigated; even at sites that fulfil the physical requirements to enable the process to occur, researchers report inconsistency in the presence offield evidence and the supercooled signature in meltwater temperature measurements (e.g. Tweed et al., 2005). Over the last fifteen years there has been robust debate regarding i) the link between glaciohydraulic supercooling and the formation of thick sequences of basal ice (e.g. Cook et al.,2007; Larson et al., 2010; Cook et al., 2010, 2011), iii) the potential for silt dominance in basal ice sequences to be used as a diagnostic indicator of the process (e.g. Evenson et al., 1999; Larson etal., 2006; Cook et al., 2011, 2012) and iii) the degree to which landform-sediment assemblages can be attributed to super cooling (e.g. Larson et al., 2006; Evans, 2009). Some of these issues are considered elsewhere in this volume. Here we summarise evidence of super cooling from Skeiðarárjökull and Skaftafellsjökull during a range of hydrological conditions and present evidence of associated glacial sediment entrainment

The screams all sound the same : the music of Of Monsters and Men and the Icelandic imaginary as geographical discourse

Over the last two decades, a substantial body of geographical research has emerged examining the mutually generative relations between music, space, place, landscape, identity and locality. This work has revealed the complex ways in which specific geographical identities and imaginaries can be reinforced and created through differences in sound, through lyrics, and through the acts and meanings of making music. Yet, these identities and imaginaries can also perform important economic functions, representing geographical discourses that musicians can employ to develop distinctiveness to make themselves marketable, particularly in the context of a heavily-saturated contemporary global music market. In this paper, we examine this with specific relation to the Icelandic band, Of Monsters and Men. We provide an account of how references to landscape and folklore in the band’s music, lyrics and imagery represent not only expressions of intimate connections with local landscape, cultural identity and lived experience, but also embody awareness of a pre-existing Icelandic imaginary. The use of folk music instruments, cultural references and motifs, we argue, acts to legitimise the band’s use of this imaginary. Further, we highlight explicit attempts to brand Icelandic music under a single ‘label’ as representative of the way in which this Icelandic imaginary comes to represent a powerful, if potentially homogenising, geographical discourse to mark out Icelandic music in a crowded global music market

Students as co-learners - reviewing a decade of the Geography Research Assistantship

Increasing attention is focusing on the creation of academic spaces in which students can engage with research and inquiry. This paper reports on the Geography Research Assistantship (GRA) module developed and implemented in Geography at Staffordshire University and reviews its contribution to student learning over the last decade. The GRA offers final year undergraduate students the opportunity to work as research assistants to members of staff and external collaborators. The experiences of students, staff and external collaborators involved in a range of research assistantships over the last ten years are reviewed and the main benefits, challenges and impacts of the initiative are analysed. The GRA engenders co-learning environments, characterised by engagement in the iterative practices of research and inquiry and the development of confidence, internal authority and self-authorship. Some students experience unease in adjusting to the liminal learning spaces inherent in the GRA and there are tensions in the exclusivity of the initiative. Evidence underscores the value of cultivating co-learning relationships and environments for mutual benefit and we encourage others to identify opportunities for adopting similar initiatives

The screams all sound the same : the music of Of Monsters and Men and the Icelandic imaginary as geographical discourse

Over the last two decades, a substantial body of geographical research has emerged examining the mutually generative relations between music, space, place, landscape, identity and locality. This work has revealed the complex ways in which specific geographical identities and imaginaries can be reinforced and created through differences in sound, through lyrics, and through the acts and meanings of making music. Yet, these identities and imaginaries can also perform important economic functions, representing geographical discourses that musicians can employ to develop distinctiveness to make themselves marketable, particularly in the context of a heavily-saturated contemporary global music market. In this paper, we examine this with specific relation to the Icelandic band, Of Monsters and Men. We provide an account of how references to landscape and folklore in the band’s music, lyrics and imagery represent not only expressions of intimate connections with local landscape, cultural identity and lived experience, but also embody awareness of a pre-existing Icelandic imaginary. The use of folk music instruments, cultural references and motifs, we argue, acts to legitimise the band’s use of this imaginary. Further, we highlight explicit attempts to brand Icelandic music under a single ‘label’ as representative of the way in which this Icelandic imaginary comes to represent a powerful, if potentially homogenising, geographical discourse to mark out Icelandic music in a crowded global music market

Deglaciation and proglacial lakes

Glaciers and ice sheets are important constituents of the Earth's land surface. Current worldwide retreat of glaciers has implications for the environment and for civilisation. There are a range of geomorphic changes occurring in cold environments and it is anticipated that these will be accentuated as a consequence of climate change. In particular, the number and size of proglacial lakes is currently increasing as a result of deglaciation and their significance for the physical environment and for society is becoming increasingly apparent. This article provides an overview of the major interdependent relationships between climate change, glaciers and proglacial lake development. In particular, it describes the key processes and impacts associated with proglacial lake evolution with reference to examples drawn from the European Alps, North America, the Himalayas, the Andes, Greenland, New Zealand and Icelan

Assessing the landscape visual quality of Shar Planina, North Macedonia

Context Landscape quality assessment provides a contextual basis for integrating cultural ecosystem services within landscape management and policy. However, measuring landscape visual quality remains a challenge; especially in the Balkans with its complex environmental and socio-cultural history. Objectives In response, we present a first assessment of landscape visual quality across Shar Planina, North Macedonia and test the transferability of a visual quality assessment method (VQI) originally developed to evaluate Northwest European landscapes. Methods This study includes remote (GIS) and field assessment. The latter produced quality measures which were summarized, scaled and weighted into an index (0 – 1.0) and served as a ground-truth dataset for subsequent GIS assessment. To assess how spatial scale affects the VQI and what scale is most appropriate to capture perceived landscape quality, the remote assessment was applied at scales ranging from 1 to 5 km2 and results were then correlated to field assessment results. Results Values for the field VQI range from 0.2 to 0.82 whilst the values from the remote assessment applied at 1 km2 range from 0.1 to 0.74 and increase to 0.77, 0.84 and 0.86 at 2 km2, 3 km2 and 5 km2 respectively. Strongest correlation between the GIS and the field assessment was observed at 2 km2, which captured detail whilst remaining appropriate to the perceived landscape. Conclusions Our research allows consideration of this cultural ecosystem service within the wider conservation efforts on Shar Planina and provides methodological guidelines for assessments of visual quality of mountainous landscapes elsewhere in the region

Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier

The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable ‘cap’ of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m−2 day−1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m−2 day−1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (−60.2‰ to −7.6‰ for δ13CCH4 and −324.3‰ to +161.1‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere

Ice-Dammed Lake Drainage Evolution at Russell Glacier, West Greenland

KEY POINTS/HIGHLIGHTSTwo rapid ice-dammed lake drainage events gauged and ice dam geometry measured.A melt enlargement model is developed to examine the evolution of drainage mechanism(s).Lake temperature dominated conduit melt enlargement and we hypothesize a flotation trigger.Glaciological and hydraulic factors that control the timing and mechanisms of glacier lake outburst floods (GLOFs) remain poorly understood. This study used measurements of lake level at 15 min intervals and known lake bathymetry to calculate lake outflow during two GLOF events from the northern margin of Russell Glacier, west Greenland. We used measured ice surface elevation, interpolated subglacial topography and likely conduit geometry to inform a melt enlargement model of the outburst evolution. The model was tuned to best-fit the hydrograph rising limb and timing of peak discharge in both events; it achieved Mean Absolute Errors of <5%. About one third of the way through the rising limb, conduit melt enlargement became the dominant drainage mechanism. Lake water temperature, which strongly governed the enlargement rate, preconditioned the high peak discharge and short duration of these floods. We hypothesize that both GLOFs were triggered by ice dam flotation, and localized hydraulic jacking sustained most of their early-stage outflow, explaining the particularly rapid water egress in comparison to that recorded at other ice-marginal lakes. As ice overburden pressure relative to lake water hydraulic head diminished, flow became confined to a subglacial conduit. This study has emphasized the inter-play between ice dam thickness and lake level, drainage timing, lake water temperature and consequently rising stage lake outflow and flood evolution

Ice‐marginal proglacial lakes across Greenland: Present status and a possible future

Ice-marginal lakes can affect glacier dynamics but are ignored in studies of the evolution of the Greenland ice sheet (GrIS) and of peripheral mountain glaciers and ice caps (PGICs). Here we show that lakes occupy 10 % of the GrIS ice margin and occur on 5 % of PGICs. Ice velocity at the GrIS margin is enhanced by ∼ 25 % at lakes versus on land. Mean ice discharge into lakes is ∼ 4.9 Gt.yr, which is ∼1 % of ice discharged through marine termini. We locate thousands of subglacial overdeepenings within which 7,404 km2 of future lakes could form, all of which will be ice-marginal at some time. Future lakes in the west and east will be restricted to the margin of the GrIS and within alpine valleys, respectively. This status and possible future leads us to contend that lakes should be incorporated into projections of Greenland ice loss

Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier

The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable ‘cap’ of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m-2 day-1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m-2 day-1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (-60.2 ‰ to -7.6 ‰ for δ13CCH4 and -324.3 ‰ to +161.1 ‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere