Internal Structure of Sandy Glacier, Southern Victoria Land, Antarctica

Dort, Wakefield

doi:10.1017/s0022143000019742

Cited by 10 publications

(6 citation statements)

References 4 publications

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“…An important outcome of differential ablation caused by surface sediment accumulation is the development of hollows, ice cliffs, ponds and streams (Dort, ; Iwata et al ., ) (Figure ). Such morphological and hydrological changes have implications for understanding and subsequently modelling drainage processes on glacier surfaces.…”

Section: Discussionmentioning

confidence: 99%

Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica

MacDonell

Fitzsimons

Mölg

2012

Hydrological Processes

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Cold‐based glaciers exist in low temperature and low humidity environments in which shortwave radiation is the largest source of energy to the glacier surface and the energy budget is very sensitive to the surface albedo. Consequently, the presence of relatively low volumes of debris on glacier surfaces has a significant impact on the timing, magnitude and rate of ablation at the surface. The aim of this study is to understand how the presence of sediment on the glacier surface at the start of the melt season can affect meltwater generation and delivery on a cold‐based glacier. A combination of field measurements, energy balance modelling and chemical mixing modelling were used on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica, between October 2005 and January 2006 to address this aim. In this system, sediment was transported onto the glacier surface during the winter months (March–October) by foehn winds, which reduced surface albedo at the start of the summer melt season. The areas of the glacier on which sediment accumulated began to melt earlier than other parts of the glacier and experienced a longer melt season. Over the study period, the total ablation on the dirty surfaces was nine times greater than for clean ice. Ablation on the dirty surfaces is dominated by melting, whereas sublimation dominates the clean ice. As the sediment was unevenly distributed over the glacier surface, the variation in melt amount and timing drove the development of a cryoconite hole system. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica

MacDonell

Fitzsimons

Mölg

2012

Hydrological Processes

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“…Distinctly different behavior can be inferred from observations in cold englacial debris bands with more densely packed debris. Among the most striking examples of this are the observations of Wakefield Dort, Jr. and colleagues at Sandy Glacier, Wright Valley, Antarctica [ Dort , ; Dort et al, ]. During a fortuitous visit in 1965, these authors found extensive exposures of interbedded glacier ice and frozen sand emerging near the glacier terminus.…”

Section: Field Observationsmentioning

confidence: 90%

“…The relatively small size and angular edges of the sandy blocks and the clear ductile distortion of the surrounding ice (visible due to alternating clear and bubbly ice layers) attest to the relatively strong, rigid behavior of the frozen sand. This figure is reproduced from Dort [] with permission from the International Glaciological Society and the photographer, Dr. Wakefiled Dort Jr.…”

Section: Field Observationsmentioning

confidence: 99%

Deformation of debris-ice mixtures

2014

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Mixtures of rock debris and ice are common in high-latitude and high-altitude environments and are thought to be widespread elsewhere in our solar system. In the form of permafrost soils, glaciers, and rock glaciers, these debris-ice mixtures are often not static but slide and creep, generating many of the landforms and landscapes associated with the cryosphere. In this review, a broad range of field observations, theory, and experimental work relevant to the mechanical interactions between ice and rock debris are evaluated, with emphasis on the temperature and stress regimes common in terrestrial surface and near-surface environments. The first-order variables governing the deformation of debris-ice mixtures in these environments are debris concentration, particle size, temperature, solute concentration (salinity), and stress. A key observation from prior studies, consistent with expectations, is that debris-ice mixtures are usually more resistant to deformation at low temperatures than their pure end-member components. However, at temperatures closer to melting, the growth of unfrozen water films at ice-particle interfaces begins to reduce the strengthening effect and can even lead to profound weakening. Using existing quantitative relationships from theoretical and experimental work in permafrost engineering, ice mechanics, and glaciology combined with theory adapted from metallurgy and materials science, a simple constitutive framework is assembled that is capable of capturing most of the observed dynamics. This framework highlights the competition between the role of debris in impeding ice creep and the mitigating effects of unfrozen water at debris-ice interfaces.

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“…The expected rapid response of snowpacks to atmospheric conditions could also make them a good proxy for short-term climate change. However, despite the important role buried snowpacks play in the Antarctic (Dort 1967), there is very little knowledge regarding the stability and durability of such snowpacks in the Dry Valleys.…”

Section: Introductionmentioning

confidence: 99%

Formation and evolution of buried snowpack deposits in Pearse Valley, Antarctica, and implications for Mars

et al. 2012

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Buried snowpack deposits are found within the McMurdo Dry Valleys of Antarctica, which offers the opportunity to study these layered structures of sand and ice within a polar desert environment. Four discrete buried snowpacks are studied within Pearse Valley, Antarctica, through in situ observations, sample analyses, O-H isotope measurements and numerical modelling of snowpack stability and evolution. The buried snowpack deposits evolve throughout the year and undergo deposition, melt, refreeze, and sublimation. We demonstrate how the deposition and subsequent burial of snow can preserve the snowpacks in the Dry Valleys. The modelled lifetimes of the buried snowpacks are dependent upon subsurface stratigraphy but are typically less than one year if the lag thickness is less than c. 7 cm and snow thickness is less than c. 10 cm, indicating that some of the Antarctic buried snowpacks form annually. Buried snowpacks in the Antarctic polar desert may serve as analogues for similar deposits on Mars and may be applicable to observations of the north polar erg, buried ice at the Mars Phoenix landing site, and observations of buried ice throughout the martian Arctic. Numerical modelling suggests that seasonal snows and subsequent burial are not required to preserve the snow and ice on Mars.

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Internal Structure of Sandy Glacier, Southern Victoria Land, Antarctica

Cited by 10 publications

References 4 publications

Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica

Seasonal sediment fluxes forcing supraglacial melting on the Wright Lower Glacier, McMurdo Dry Valleys, Antarctica

Deformation of debris-ice mixtures

Formation and evolution of buried snowpack deposits in Pearse Valley, Antarctica, and implications for Mars

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