New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland
The complexity of the Krafla volcano and its geothermal system(s) has puzzled geoscientists for decades. New and old geoscientific studies are reviewed in order to shed some light on this complexity. The geological structure and history of the volcano is more complex than hitherto believed. The visi...
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ftdoajarticles:oai:doaj.org/article:369bd3a6dece4293b2e7f0aa70ecc42e 2023-05-15T16:50:53+02:00 New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland Knútur Árnason 2020-01-01T00:00:00Z https://doi.org/10.3390/geosciences10010034 https://doaj.org/article/369bd3a6dece4293b2e7f0aa70ecc42e EN eng MDPI AG https://www.mdpi.com/2076-3263/10/1/34 https://doaj.org/toc/2076-3263 2076-3263 doi:10.3390/geosciences10010034 https://doaj.org/article/369bd3a6dece4293b2e7f0aa70ecc42e Geosciences, Vol 10, Iss 1, p 34 (2020) krafla volcano geothermal systems conceptual models volcanology Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.3390/geosciences10010034 2022-12-31T12:00:13Z The complexity of the Krafla volcano and its geothermal system(s) has puzzled geoscientists for decades. New and old geoscientific studies are reviewed in order to shed some light on this complexity. The geological structure and history of the volcano is more complex than hitherto believed. The visible 110 ka caldera hosts, now buried, an 80 ka inner caldera. Both calderas are bisected by an ESE-WNW transverse low-density structure. Resistivity surveys show that geothermal activity has mainly been within the inner caldera but cut through by the ESE-WNW structure. The complexity of the geothermal system in the main drill field can be understood by considering the tectonic history. Isotope composition of the thermal fluids strongly suggests at least three different geothermal systems. Silicic magma encountered in wells K-39 and IDDP-1 indicates a hitherto overlooked heat transport mechanism in evolved volcanos. Basaltic intrusions into subsided hydrothermally altered basalt melt the hydrated parts, producing a buoyant silicic melt which migrates upwards forming sills at shallow crustal levels which are heat sources for the geothermal system above. This can explain the bimodal behavior of evolved volcanos like Krafla and Askja, with occasional silicic, often phreatic, eruptions but purely basaltic in-between. When substantial amounts of silicic intrusions/magma have accumulated, major basalt intrusion(s) may “ignite” them causing a silicic eruption. Article in Journal/Newspaper Iceland Directory of Open Access Journals: DOAJ Articles Askja ENVELOPE(-16.802,-16.802,65.042,65.042) Krafla ENVELOPE(-16.747,-16.747,65.713,65.713) Geosciences 10 1 34 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
krafla volcano geothermal systems conceptual models volcanology Geology QE1-996.5 |
spellingShingle |
krafla volcano geothermal systems conceptual models volcanology Geology QE1-996.5 Knútur Árnason New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
topic_facet |
krafla volcano geothermal systems conceptual models volcanology Geology QE1-996.5 |
description |
The complexity of the Krafla volcano and its geothermal system(s) has puzzled geoscientists for decades. New and old geoscientific studies are reviewed in order to shed some light on this complexity. The geological structure and history of the volcano is more complex than hitherto believed. The visible 110 ka caldera hosts, now buried, an 80 ka inner caldera. Both calderas are bisected by an ESE-WNW transverse low-density structure. Resistivity surveys show that geothermal activity has mainly been within the inner caldera but cut through by the ESE-WNW structure. The complexity of the geothermal system in the main drill field can be understood by considering the tectonic history. Isotope composition of the thermal fluids strongly suggests at least three different geothermal systems. Silicic magma encountered in wells K-39 and IDDP-1 indicates a hitherto overlooked heat transport mechanism in evolved volcanos. Basaltic intrusions into subsided hydrothermally altered basalt melt the hydrated parts, producing a buoyant silicic melt which migrates upwards forming sills at shallow crustal levels which are heat sources for the geothermal system above. This can explain the bimodal behavior of evolved volcanos like Krafla and Askja, with occasional silicic, often phreatic, eruptions but purely basaltic in-between. When substantial amounts of silicic intrusions/magma have accumulated, major basalt intrusion(s) may “ignite” them causing a silicic eruption. |
format |
Article in Journal/Newspaper |
author |
Knútur Árnason |
author_facet |
Knútur Árnason |
author_sort |
Knútur Árnason |
title |
New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
title_short |
New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
title_full |
New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
title_fullStr |
New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
title_full_unstemmed |
New Conceptual Model for the Magma-Hydrothermal-Tectonic System of Krafla, NE Iceland |
title_sort |
new conceptual model for the magma-hydrothermal-tectonic system of krafla, ne iceland |
publisher |
MDPI AG |
publishDate |
2020 |
url |
https://doi.org/10.3390/geosciences10010034 https://doaj.org/article/369bd3a6dece4293b2e7f0aa70ecc42e |
long_lat |
ENVELOPE(-16.802,-16.802,65.042,65.042) ENVELOPE(-16.747,-16.747,65.713,65.713) |
geographic |
Askja Krafla |
geographic_facet |
Askja Krafla |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Geosciences, Vol 10, Iss 1, p 34 (2020) |
op_relation |
https://www.mdpi.com/2076-3263/10/1/34 https://doaj.org/toc/2076-3263 2076-3263 doi:10.3390/geosciences10010034 https://doaj.org/article/369bd3a6dece4293b2e7f0aa70ecc42e |
op_doi |
https://doi.org/10.3390/geosciences10010034 |
container_title |
Geosciences |
container_volume |
10 |
container_issue |
1 |
container_start_page |
34 |
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1766040996043292672 |