A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden
Electrical resistivity tomography (ERT) is a commonly used geophysical method to investigate permafrost in the mountain environment, but few studies have employed this method in a permafrost affected peatland. For this thesis, 5 ERT profiles were measured over 17 palsas and peat-plateaus in a palsa...
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Uppsala universitet, Luft-, vatten- och landskapslära
2014
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ftuppsalauniv:oai:DiVA.org:uu-219932 2023-05-15T15:18:25+02:00 A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden Undersökning av palsar med hjälp av elektrisk resistivitetstomografi i Tavvavuoma, norra Sverige Marklund, Per 2014 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219932 eng eng Uppsala universitet, Luft-, vatten- och landskapslära Examensarbete vid Institutionen för geovetenskaper, 1650-6553 276 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219932 info:eu-repo/semantics/openAccess Palsas permafrost peat plateaus resistivity ert geophysics Tavvavuoma Palsar torvplatåer resistivitet geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap Student thesis info:eu-repo/semantics/bachelorThesis text 2014 ftuppsalauniv 2023-02-23T21:52:07Z Electrical resistivity tomography (ERT) is a commonly used geophysical method to investigate permafrost in the mountain environment, but few studies have employed this method in a permafrost affected peatland. For this thesis, 5 ERT profiles were measured over 17 palsas and peat-plateaus in a palsa peatland environment in Tavvavuoma, northern Sweden, where the primary aim was to investigate the depth to the base of permafrost under the mounds. These depths are also used to estimate the excess ice fraction (EIF), which is indicative of the proportion of segregation ice in the frozen core under the mounds. The internal structure of palsas and the spatial distribution of permafrost was also investigated from the inverted resistivity models. Permafrost thickness was found to range from 5 – 17 m, with the thickest permafrost in the west end of the study area. EIF values range between 0,04 to 0,58, with the lowest values in the same end as the deepest permafrost, where also low mound elevations are found. The deep permafrost combined with low mound elevations are suggested to be attributed to the presence of coarse grained (glaciofluvial) sediments where ice segregation formation is limited, thus small amounts of frost heave. Deep permafrost is possibly underlying at least two thermokarst depressions/fens in the area, which is suggested to obstruct their drainage. The height of the mounds was surprisingly found to decrease with permafrost thickness, a relationship that is likely to be an effect of the varied underlying sediment cover. This thesis demonstrates the applicability of ERT in peatland permafrost research, but also considers the limitations of the method. Elektrisk resistivitetstomografi (ERT) är en geofysisk metod som har använts flitigt vid undersökningar av alpin permafrost, men få studier har hittills tillämpat denna teknik vid undersökningar av permafrost i myrmarker. Under detta examensarbete på masternivå mättes 5 ERT-profiler över 17 palsar samt torvplatåer i ett palsmyrkomplex med sporadisk ... Bachelor Thesis Arctic Ice Norra Sverige Northern Sweden palsa palsas Peat permafrost Thermokarst Uppsala University: Publications (DiVA) Arctic Tavvavuoma ENVELOPE(20.860,20.860,68.520,68.520) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Palsas permafrost peat plateaus resistivity ert geophysics Tavvavuoma Palsar torvplatåer resistivitet geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap |
spellingShingle |
Palsas permafrost peat plateaus resistivity ert geophysics Tavvavuoma Palsar torvplatåer resistivitet geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap Marklund, Per A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
topic_facet |
Palsas permafrost peat plateaus resistivity ert geophysics Tavvavuoma Palsar torvplatåer resistivitet geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap |
description |
Electrical resistivity tomography (ERT) is a commonly used geophysical method to investigate permafrost in the mountain environment, but few studies have employed this method in a permafrost affected peatland. For this thesis, 5 ERT profiles were measured over 17 palsas and peat-plateaus in a palsa peatland environment in Tavvavuoma, northern Sweden, where the primary aim was to investigate the depth to the base of permafrost under the mounds. These depths are also used to estimate the excess ice fraction (EIF), which is indicative of the proportion of segregation ice in the frozen core under the mounds. The internal structure of palsas and the spatial distribution of permafrost was also investigated from the inverted resistivity models. Permafrost thickness was found to range from 5 – 17 m, with the thickest permafrost in the west end of the study area. EIF values range between 0,04 to 0,58, with the lowest values in the same end as the deepest permafrost, where also low mound elevations are found. The deep permafrost combined with low mound elevations are suggested to be attributed to the presence of coarse grained (glaciofluvial) sediments where ice segregation formation is limited, thus small amounts of frost heave. Deep permafrost is possibly underlying at least two thermokarst depressions/fens in the area, which is suggested to obstruct their drainage. The height of the mounds was surprisingly found to decrease with permafrost thickness, a relationship that is likely to be an effect of the varied underlying sediment cover. This thesis demonstrates the applicability of ERT in peatland permafrost research, but also considers the limitations of the method. Elektrisk resistivitetstomografi (ERT) är en geofysisk metod som har använts flitigt vid undersökningar av alpin permafrost, men få studier har hittills tillämpat denna teknik vid undersökningar av permafrost i myrmarker. Under detta examensarbete på masternivå mättes 5 ERT-profiler över 17 palsar samt torvplatåer i ett palsmyrkomplex med sporadisk ... |
format |
Bachelor Thesis |
author |
Marklund, Per |
author_facet |
Marklund, Per |
author_sort |
Marklund, Per |
title |
A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
title_short |
A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
title_full |
A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
title_fullStr |
A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
title_full_unstemmed |
A 2D Electrical Resistivity Survey of Palsas in Tavvavuoma, sub-arctic Sweden |
title_sort |
2d electrical resistivity survey of palsas in tavvavuoma, sub-arctic sweden |
publisher |
Uppsala universitet, Luft-, vatten- och landskapslära |
publishDate |
2014 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219932 |
long_lat |
ENVELOPE(20.860,20.860,68.520,68.520) |
geographic |
Arctic Tavvavuoma |
geographic_facet |
Arctic Tavvavuoma |
genre |
Arctic Ice Norra Sverige Northern Sweden palsa palsas Peat permafrost Thermokarst |
genre_facet |
Arctic Ice Norra Sverige Northern Sweden palsa palsas Peat permafrost Thermokarst |
op_relation |
Examensarbete vid Institutionen för geovetenskaper, 1650-6553 276 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219932 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766348609452769280 |