Krzysztof (2017) On the potential for a bottom active layer below coastal permafrost: the impact of seawater on permafrost degradation imaged by electrical resistivity tomography (Hornsund, SW Spitsbergen Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.

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ABSTRACT. Glacier naledi are extrusive ice masses that appear in front of glaciers as a consequence of refreezing of meltwater seepage during the accumulation season. These structures provide a unique opportunity to understand subglacial drainage activity during the accumulation season; however, only few detailed studies have previously focused on their characteristics. Here, we investigated glacierderived naled assemblages in the proglacial zone of the polythermal glacier Werenskioldbreen (27.4 km 2 ) in SW Svalbard. We determined the spatial distribution of naledi using ground penetrating radar surveys. The main subglacial drainage pattern was related to a channel under the medial moraine, and three sources are linked to a distributed subglacial drainage network. The relation between atmospherically-corrected (Ca 2+ + Mg 2+) and (SO 4 2− ) in sub-naled waters was closely related to sulphide oxidation coupled with carbonate dissolution (r = 0.99; slope = 1.6). This is consistent with the local lithology, which is dominated by schist containing carbonates. We also found high carbonate saturation indices in pale white ice layers within the naled. We conclude that sulphide oxidation coupled with carbonate dissolution is the dominant chemical weathering process in the subglacial drainage system of Werenskioldbreen during the accumulation season.

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Soil piping leads to land degradation in almost all morphoclimatic regions. However, the detection of soil pipes is still a methodological challenge. Therefore, this study aims at testing ground penetrating radar (GPR) to identify soil pipes and to present the complexity of soil pipe networks. The GPR surveys were conducted at three sites in the Bieszczady Mountains (SE Poland), where pipes develop in Cambisols. In total, 36 GPR profiles longitudinal and transverse to piping systems were made and used to provide spatial visualization of pipe networks. Soil pipes were identified as reflection hyperbolas on radargrams, which were verified with the surface indicators of piping, i.e., sagging of the ground and the occurrence of pipe roof collapses. Antennas of 500 MHz and 800 MHz were tested, which made possible the penetration of the subsurface up to 3.2 m and 2 m, respectively. Concerning ground properties, antenna frequencies and processing techniques, there was a potential possibility to detect pipes with a minimum diameter of 3.5 cm (using the antenna of lower frequency), and 2.2 cm (with the antenna of higher frequency). The results have proved that soil pipes meander horizontally and vertically and their networks become more complicated and extensive down the slope. GPR is a useful method to detect soil pipes, although it requires field verification and the proper selection of antenna frequency.

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Talus slopes are a common sedimentary formation both in polar and high-mountain areas, but their development is still not sufficiently understood. This article discusses the environmental factors that have been influencing development of talus slopes since the deglaciation and their impact on the internal structure of slopes. Case studies of the slopes from SW Spitsbergen and the Tatra Mountains in Poland were compared in order to explore different evolution stages. Slopes’ structure was analysed using geophysical surveys based on two-dimensional electrical resistivity tomography (ERT) with a Wenner-Schlumberger array and an electrode spacing of 5 m, combined with geomorphological observations. The investigated talus slopes represent the paraglacial, periglacial and talus-alluvial environments. New data on the internal structure of talus slopes developing in the present or past glaciated areas adds to understanding talus slope evolution. There are many different views concerning the development of slopes during the paraglacial period, whose analysis seems to be crucial in the background of climate change and their record in slope structures. In addition, the study provided valuable information on the development and degradation of permafrost in slope materials.

The location of Svalbard at the interface between the warm Atlantic and cold Arctic oceans causes the terrestrial environment to be highly sensitive to contemporary climate warming. Talus slopes provide a component of glaciated areas that has been registering these changes on a scale of several thousand years. However, knowledge about their development during glacial recession is still limited. This paper fills this gap by providing unique data obtained by geophysical methods: electrical resistivity tomography (ERT) and ground-penetrating radar (GPR), regarding the talus slopes in Revdalen (SW Spitsbergen), which was last glaciated in the Neoglacial period. The results indicate that the thickness of talus slopes depends first of all on the size of the sediment supply area and only secondarily on the stage of development. The initial content of buried glacial ice in the talus deposits is differential and depends on both the rate of deglaciation and the local intensity of rock wall denudation. Over time, as a result of creep, the presence of massive ice is limited to ever lower parts of the slope. Above, there is aggradation of pore ice in delivered debris material. At the end of this stage, the buried glacial ice can form, or co-create together with pore ice, the core of subslope rock glaciers. The relatively long period since the beginning of the Revdalen deglaciation allowed a general model of the development of talus slopes in the polar environment to be prepared.