Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content

With the aim of monitoring the dynamics of the Livingston Island ice cap, the Departament de Geodinàmica i Geofísica of the Universitat de Barcelona began ye a r ly surveys in the austral summer of 1994-95 on Johnsons Glacier. During this field campaign 10 shallow ice cores were sampled with a manua...

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Autores: Furdada i Bellavista, Glòria, Pourchet, M., Vilaplana, Joan Manuel
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:1999
País:España
Recursos:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositório:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/33148
Acesso em linha:https://hdl.handle.net/2445/33148
Access Level:Acceso aberto
Palavra-chave:Glaceres
Geomorfologia glacial
Livingston (Shetland del Sud : Illa)
Antàrtida
Glaciers
Glacial landforms
Livingston Island (South Shetland Islands)
Antarctica
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spelling Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs contentFurdada i Bellavista, GlòriaPourchet, M.Vilaplana, Joan ManuelGlaceresGeomorfologia glacialLivingston (Shetland del Sud : Illa)AntàrtidaGlaciersGlacial landformsLivingston Island (South Shetland Islands)AntarcticaWith the aim of monitoring the dynamics of the Livingston Island ice cap, the Departament de Geodinàmica i Geofísica of the Universitat de Barcelona began ye a r ly surveys in the austral summer of 1994-95 on Johnsons Glacier. During this field campaign 10 shallow ice cores were sampled with a manual ve rtical ice-core drilling machine. The objectives were: i) to detect the tephra layer accumulated on the glacier surface, attributed to the 1970 Deception Island pyroclastic eruption, today interstratified; ii) to verify wheter this layer might serve as a reference level; iii) to measure the 1 3 7Cs radio-isotope concentration accumulated in the 1965 snow stratum; iv) to use the isochrone layer as a mean of verifying the age of the 1970 tephra layer; and, v) to calculate both the equilibrium line of the glacier and average mass balance over the last 28 years (1965-1993). The stratigr a p hy of the cores, their cumulative density curves and the isothermal ice temperatures recorded confi rm that Johnsons Glacier is a temperate glacier. Wi n d, solar radiation heating and liquid water are the main agents controlling the ve rtical and horizontal redistribution of the volcanic and cryoclastic particles that are sedimented and remain interstratified within the g l a c i e r. It is because of this redistribution that the 1970 tephra layer does not always serve as a ve ry good reference level. The position of the equilibrium line altitude (ELA) in 1993, obtained by the 1 3 7Cs spectrometric analysis, varies from about 200 m a.s.l. to 250 m a.s.l. This indicates a rising trend in the equilibrium line altitude from the beginning of the 1970s to the present day. The va rying slope orientation of Johnsons Glacier relative to the prevailing NE wind gives rise to large local differences in snow accumulation, which locally modifies the equilibrium line altitude. In the cores studied, 1 3 7Cs appears to be associated with the 1970 tephra laye r. This indicates an intense ablation episode throughout the sampled area (at least up to 330 m a.s.l), which probably occurred synchronically to the 1970 tephra deposition or later. A rough estimate of the specific mass balance reveals a considerable accumulation gradient related to the increase with altitude.Universitat de Barcelona (UB). Institut de Cièncias de la Terra Jaume Almera (ICTJA)2012201219992012info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersion12 p.application/pdfhttps://hdl.handle.net/2445/33148Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésReproducció del document publicat a: http://www.raco.cat/index.php/ActaGeologica/article/view/75660Acta Geologica Hispanica, 1999, vol. 34, num. 4, p. 391-402(c) Furdada i Bellavista, Glòria et al., 1999info:eu-repo/semantics/openAccessoai:recercat.cat:2445/331482026-05-29T05:05:01Z
dc.title.none.fl_str_mv Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
title Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
spellingShingle Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
Furdada i Bellavista, Glòria
Glaceres
Geomorfologia glacial
Livingston (Shetland del Sud : Illa)
Antàrtida
Glaciers
Glacial landforms
Livingston Island (South Shetland Islands)
Antarctica
title_short Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
title_full Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
title_fullStr Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
title_full_unstemmed Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
title_sort Study of Johnsons Glacier (Livingston Island, Antarctica) by means of shallow ice cores and their tephra and by analysis of 137Cs content
dc.creator.none.fl_str_mv Furdada i Bellavista, Glòria
Pourchet, M.
Vilaplana, Joan Manuel
author Furdada i Bellavista, Glòria
author_facet Furdada i Bellavista, Glòria
Pourchet, M.
Vilaplana, Joan Manuel
author_role author
author2 Pourchet, M.
Vilaplana, Joan Manuel
author2_role author
author
dc.subject.none.fl_str_mv Glaceres
Geomorfologia glacial
Livingston (Shetland del Sud : Illa)
Antàrtida
Glaciers
Glacial landforms
Livingston Island (South Shetland Islands)
Antarctica
topic Glaceres
Geomorfologia glacial
Livingston (Shetland del Sud : Illa)
Antàrtida
Glaciers
Glacial landforms
Livingston Island (South Shetland Islands)
Antarctica
description With the aim of monitoring the dynamics of the Livingston Island ice cap, the Departament de Geodinàmica i Geofísica of the Universitat de Barcelona began ye a r ly surveys in the austral summer of 1994-95 on Johnsons Glacier. During this field campaign 10 shallow ice cores were sampled with a manual ve rtical ice-core drilling machine. The objectives were: i) to detect the tephra layer accumulated on the glacier surface, attributed to the 1970 Deception Island pyroclastic eruption, today interstratified; ii) to verify wheter this layer might serve as a reference level; iii) to measure the 1 3 7Cs radio-isotope concentration accumulated in the 1965 snow stratum; iv) to use the isochrone layer as a mean of verifying the age of the 1970 tephra layer; and, v) to calculate both the equilibrium line of the glacier and average mass balance over the last 28 years (1965-1993). The stratigr a p hy of the cores, their cumulative density curves and the isothermal ice temperatures recorded confi rm that Johnsons Glacier is a temperate glacier. Wi n d, solar radiation heating and liquid water are the main agents controlling the ve rtical and horizontal redistribution of the volcanic and cryoclastic particles that are sedimented and remain interstratified within the g l a c i e r. It is because of this redistribution that the 1970 tephra layer does not always serve as a ve ry good reference level. The position of the equilibrium line altitude (ELA) in 1993, obtained by the 1 3 7Cs spectrometric analysis, varies from about 200 m a.s.l. to 250 m a.s.l. This indicates a rising trend in the equilibrium line altitude from the beginning of the 1970s to the present day. The va rying slope orientation of Johnsons Glacier relative to the prevailing NE wind gives rise to large local differences in snow accumulation, which locally modifies the equilibrium line altitude. In the cores studied, 1 3 7Cs appears to be associated with the 1970 tephra laye r. This indicates an intense ablation episode throughout the sampled area (at least up to 330 m a.s.l), which probably occurred synchronically to the 1970 tephra deposition or later. A rough estimate of the specific mass balance reveals a considerable accumulation gradient related to the increase with altitude.
publishDate 1999
dc.date.none.fl_str_mv 1999
2012
2012
2012
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/33148
url https://hdl.handle.net/2445/33148
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció del document publicat a: http://www.raco.cat/index.php/ActaGeologica/article/view/75660
Acta Geologica Hispanica, 1999, vol. 34, num. 4, p. 391-402
dc.rights.none.fl_str_mv (c) Furdada i Bellavista, Glòria et al., 1999
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) Furdada i Bellavista, Glòria et al., 1999
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 12 p.
application/pdf
dc.publisher.none.fl_str_mv Universitat de Barcelona (UB). Institut de Cièncias de la Terra Jaume Almera (ICTJA)
publisher.none.fl_str_mv Universitat de Barcelona (UB). Institut de Cièncias de la Terra Jaume Almera (ICTJA)
dc.source.none.fl_str_mv Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812429

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