Cold-Based Glaciers

Lorrain, Réginald; Fitzsimons, Sean J.; Singh, V. P.; Singh, Paras B.; Haritashya, U. K.

doi:10.1007/978-90-481-2642-2_72

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…Consequently, the use of icings as an indicator of present polythermal glacier regimes is not supported by our study. This strengthens the argument that cold-based glacier dynamics have been oversimplified (Waller, 2001;Lorrain and Fitzsimons, 2011). Notably, icings at Scott…”

Section: Present Glacier Thermal Regimesupporting

confidence: 76%

Proglacial icings as indicators of glacier thermal regime: ice thickness changes and icing occurrence in Svalbard

Mallinson

Swift

Sole

2019

Geografiska Annaler: Series A, Physical Geography

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Proglacial icings (also known as naled or aufeis) are frequently observed in the forefields of polar glaciers. Their formation has been ascribed to the refreezing of upwelling groundwater that has originated from subglacial melt, and thus the presence of icings has been used as evidence of polythermal glacier regime. We provide an updated analysis of icing occurrence in Svalbard and test the utility of icings as an indicator of thermal regime by comparing icing presence with: (1) mean glacier thickness, as a proxy for present thermal regime; and (2) evidence of past surge activity, which is an indicator of past thermal regime. A total of 279 icings were identified from TopoSvalbard imagery covering the period 2008-2012, of which 143 corresponded to icings identified by Bukowska-Jania and Szafraniec (2005) from aerial photographs from 1990. Only 46% of icings observed in 2008-2012 were found to occur at glaciers with thicknesses consistent with a polythermal regime, meaning a large proportion were associated with glaciers predicted to be of a cold or transitional thermal regime. As a result, icing presence alone may be an unsuitable indicator of glacier regime. We further found that, of the 279 glaciers with icings, 63% of cold-based glaciers and 64% of transitional glaciers were associated with evidence of surge activity. We therefore suggest Proglacial icings as indicators of glacier thermal regime that proglacial icing formation in Svalbard may reflect historical (rather than present) thermal regime, and that icings possibly originate from groundwater effusion from subglacial taliks that persist for decades following glacier thinning and associated regime change.

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Section: Present Glacier Thermal Regimesupporting

confidence: 76%

Proglacial icings as indicators of glacier thermal regime: ice thickness changes and icing occurrence in Svalbard

Mallinson

Swift

Sole

2019

Geografiska Annaler: Series A, Physical Geography

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“…It means that between both lakes, there is no possibility of weathering processes that increase dissolved ions, as on the contrary, mineral precipitation should occur due to the lower TDS values. One possibility may be that some weathering processes may be acting at the base of the glacier as explained by Lorrain and Fitzsimons (2011), which modifies the hydrochemical signal.…”

Section: Lake Florencia's Water Source(s)mentioning

confidence: 99%

Dissolved major and trace geochemical dynamics in Antarctic lacustrine systems

et al. 2020

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Section: Research Articlementioning

confidence: 99%

“…Finally, concerning the interaction of the glacier with its underlying medium, it is modeled by assuming that they move jointly when the shear waves arrive at their common boundary. This assumption is valid for different kinds of glaciers, namely, the so called cold‐based or dry‐based glaciers, that is, those with their basal part entirely below the pressure melting point, and therefore with no liquid water occurring at the interface between the two media (Lorrain & Fitzsimons, ) and also for the more erosive “temperate” glaciers, for which thin water sheets or water‐filled holes with different shapes can exist between the glacier bottom and the rocks beneath, allowing the ice to slip and move relatively fast (Herman et al, ). It must be however noticed that in this second case some restrictions involving the frequency content of the signal and the water viscosity, among other parameters, must be taken into account for the “welded” boundary condition to be valid (Rokhlin & Wang, ).…”

Section: Introductionmentioning

confidence: 99%

SH Seismoelectric Response of a Glacier: An Analytic Study

2018

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In this work we derive the analytic solutions to the system of equations modeling, within the framework of Pride's theory, the seismic‐to‐electromagnetic conversions taking place in a glacial environment. Considering a one‐dimensional approach, we set a pure shear horizontal wave seismic source on top of an elastic medium representing the glacier, which overlies a porous medium fully saturated with water, representing the glacier bed. The obtained solutions allow to separately represent and analyze the induced electromagnetic responses, the so called coseismic waves, for both the electric and magnetic fields along with the signals originated at the glacier bottom, the electric interface response, and magnetic interface response. We also propose approximate solutions, useful to be used in a fast inversion algorithm. We analyze the characteristics of the induced electromagnetic signals and their dependence on the type of glacier bed, considering an unconsolidated one and a consolidated one. The main results of the present paper are manifold, on the one hand, the mentioned analytic solutions, on the other hand, that the electric interface response originated at the glacier bottom is proportional to the electric current density at this depth, and depends on textural and electrical properties of the basement. We also showed that the amplitude of the electric interface response is three orders of magnitude higher than the amplitude of the electric coseismic field. This fact reinforces the idea proposed in our previous works that it would be interesting to test shear horizontal seismoelectrics as a possible geophysical prospecting and monitoring tool.

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Cold-Based Glaciers

Cited by 8 publications

References 19 publications

Proglacial icings as indicators of glacier thermal regime: ice thickness changes and icing occurrence in Svalbard

Proglacial icings as indicators of glacier thermal regime: ice thickness changes and icing occurrence in Svalbard

Dissolved major and trace geochemical dynamics in Antarctic lacustrine systems

SH Seismoelectric Response of a Glacier: An Analytic Study

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