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Abstract

The analysis of climate changes in of the Tarfala valley and Kebnekaise Mts area, and changes within the range of the Scandinavian Glaciation shows that even in the warmest period of Holocene there were favourable environmental conditions for permafrost of the Pleistocene origin to be preserved in this area. The results of electrical resistivity surveys together with analysis of available publications indicate that two layers of permafrost can be distinguished in the Storglaciären forefield. The shallower, discountinuous, with thickness ca. 2–6 meters is connected to the current climate, The second, deeper located layer of permafrost, separated with talik, is older. Its thickness can reach dozens of metres and is probably the result of permafrost formation during Pleistocene. The occurrence of two-layered permafrost in the Tarfala valley in Kebnekaise area shows the evolution of mountain permafrost may be seen as analogous to that in Western Siberia. This means that the effect of climate changes gives a similar effect in permafrost formation and evolution in both altitudinal and latitudinal extent. The occurrence of two-layered permafrost in Scandes and Western Siberia plain indicates possible analogy in climatic evolution, and gives opportunity to understand them in uniform way.
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Authors and Affiliations

Wojciech Dobiński
Michał Glazer
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Abstract

Research on permafrost in the Abisko area of northern Sweden date from the 1950s. A mean annual air temperature of −3°C in the Abisko mountains (i.e. 1000 m a.s.l.) and −1°C beyond the mountain area at an altitude of around 400m suggests that both moun− tain and arctic permafrost occur there. Several geophysical surveys were performed by means of resistivity tomography (ERT) and electromagnetic mapping (EM). Wherever pos− sible the geophysical survey results were calibrated by digging tests pits. The results show that permafrost occurs extensively in the mountain areas, especially those above 900m a.s.l. and also sporadically at lower altitudes. At 400 m a.s.l. permafrost may be up to 30 m thick. Its thickness and extent are determined largely by the very variable local rock and soil con− ditions. Fossil permafrost is also likely to occur in this area.

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Authors and Affiliations

Wojciech Dobiński
ORCID: ORCID
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Abstract

This article presents the results of a geophysical survey from which detailed images of glacial and periglacial landforms and subsurface structures were obtained. Sediments and landforms on newly deglaciated terrain can be used to reconstruct the extent and character of glaciers in the past and add to the understanding of their response to climate and environmental changes. To derive spatial information from complex geomorphological terrain, joint interpretation of three non-intrusive geophysical methods were applied: Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and time-lapse Seismic Tomography. These were used to identify subsurface structures in the forefield of the retreating Hans Glacier in SW Spitsbergen, Svalbard. Three main zones were distinguished and described: outwash plain, terminal moraine from the last glacial maximum, and glacial forefield proximal to the glacier front. Geophysical profiles across these zones reveal information on glacio-fluvial sediment thickness and structure, ice thickness and structure, and bedrock topography. The freezing-thawing effect of the active layer has a strong and deep impact, as demonstrated by variations in VP (P-wave velocity) in the obtained outcomes. The results are discussed in the context of the current climate in Svalbard. This study provides a snapshot of ground parameters and the current state of the subsurface in southern Spitsbergen. The boundary between sediment-bedrock layers was estimated to be from 5 to 20 m in depth. It is the first such extensive description of periglacial structures in the forefield of the Hans Glacier, utilising the longest ERT profile (1500 m) in Svalbard together with deep GPR and precise seismic tomography.
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Authors and Affiliations

Artur Marciniak
1
ORCID: ORCID
Marzena Osuch
1
ORCID: ORCID
Tomasz Wawrzyniak
1
ORCID: ORCID
Bartosz Owoc
1
ORCID: ORCID
Wojciech Dobiński
2
ORCID: ORCID
Michał Glazer
2
Mariusz Majdański
1
ORCID: ORCID

  1. Institute of Geophysics, Polish Academy of Sciences, Warsaw, 01-452, Poland
  2. Faculty of Natural Sciences, University of Silesia, Sosnowiec, 41-200, Poland

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