Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland
Four major NE trending postglacial volcanic and tectonic fissure swarms (volcanic systems) occur on the Reykjanes Peninsula, and the westernmost three are the main subject of this paper. Two main types of basaltic volcanoes are associated with these systems: shields of picrite and olivine tholeiite...
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ftoceanrep:oai:oceanrep.geomar.de:37444 2023-05-15T16:52:03+02:00 Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland Gudmundsson, Agust 2012 text https://oceanrep.geomar.de/id/eprint/37444/ https://oceanrep.geomar.de/id/eprint/37444/1/scan_2017-04-05_13-27-49r.1111.pdf https://doi.org/10.1029/JB091iB12p12711 en eng AGU https://oceanrep.geomar.de/id/eprint/37444/1/scan_2017-04-05_13-27-49r.1111.pdf Gudmundsson, A. (2012) Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland. Journal of Geophysical Research: Solid Earth, 91 (B12). pp. 12711-12721. DOI 10.1029/JB091iB12p12711 <https://doi.org/10.1029/JB091iB12p12711>. doi:10.1029/JB091iB12p12711 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2012 ftoceanrep https://doi.org/10.1029/JB091iB12p12711 2023-04-07T15:32:34Z Four major NE trending postglacial volcanic and tectonic fissure swarms (volcanic systems) occur on the Reykjanes Peninsula, and the westernmost three are the main subject of this paper. Two main types of basaltic volcanoes are associated with these systems: shields of picrite and olivine tholeiite and tholeiite fissures. The average volume of 26 shields is 1.11 km3, and the total production is 29 km3, whereas the corresponding figures for lavas from 101 volcanic fissures are 0.11 km3 and 11 km3. The tectonic fractures are either tension fractures or normal faults of widths up to 20 m, throws up to 10 m, and lengths up to several kilometers. The volcanism and tectonics can be explained by magmatic pressure changes in ellipsoidal magma reservoirs located beneath the fissure swarms. A magmatic pressure increase of the order of 10 MPa is found to be sufficient for an excess uplift of the order of several meters, which is all that is needed to account for the fractures and measured dilation in the fissure swarms. It is concluded that most shield volcanoes, in particular the picrite shields and the large olivine tholeiite shields, formed during the early postglacial period and that their formation was facilitated by the stress field generated as a result of rapid uplift and bending of the crust above the reservoirs. Since that time the reservoirs have become independent systems, the volcanism has been confined to fissures, and the production rate has decreased significantly. During typical fissure eruptions (0.015 km3), only the uppermost several hundred meters of the source reservoir, depending on its magma content, supply magma to the eruption. Article in Journal/Newspaper Iceland OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Journal of Geophysical Research: Solid Earth 91 B12 12711 12721 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Four major NE trending postglacial volcanic and tectonic fissure swarms (volcanic systems) occur on the Reykjanes Peninsula, and the westernmost three are the main subject of this paper. Two main types of basaltic volcanoes are associated with these systems: shields of picrite and olivine tholeiite and tholeiite fissures. The average volume of 26 shields is 1.11 km3, and the total production is 29 km3, whereas the corresponding figures for lavas from 101 volcanic fissures are 0.11 km3 and 11 km3. The tectonic fractures are either tension fractures or normal faults of widths up to 20 m, throws up to 10 m, and lengths up to several kilometers. The volcanism and tectonics can be explained by magmatic pressure changes in ellipsoidal magma reservoirs located beneath the fissure swarms. A magmatic pressure increase of the order of 10 MPa is found to be sufficient for an excess uplift of the order of several meters, which is all that is needed to account for the fractures and measured dilation in the fissure swarms. It is concluded that most shield volcanoes, in particular the picrite shields and the large olivine tholeiite shields, formed during the early postglacial period and that their formation was facilitated by the stress field generated as a result of rapid uplift and bending of the crust above the reservoirs. Since that time the reservoirs have become independent systems, the volcanism has been confined to fissures, and the production rate has decreased significantly. During typical fissure eruptions (0.015 km3), only the uppermost several hundred meters of the source reservoir, depending on its magma content, supply magma to the eruption. |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, Agust |
spellingShingle |
Gudmundsson, Agust Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
author_facet |
Gudmundsson, Agust |
author_sort |
Gudmundsson, Agust |
title |
Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
title_short |
Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
title_full |
Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
title_fullStr |
Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
title_full_unstemmed |
Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland |
title_sort |
mechanical aspects of postglacial volcanism and tectonics of the reykjanes peninsula, southwest iceland |
publisher |
AGU |
publishDate |
2012 |
url |
https://oceanrep.geomar.de/id/eprint/37444/ https://oceanrep.geomar.de/id/eprint/37444/1/scan_2017-04-05_13-27-49r.1111.pdf https://doi.org/10.1029/JB091iB12p12711 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Reykjanes |
geographic_facet |
Reykjanes |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
https://oceanrep.geomar.de/id/eprint/37444/1/scan_2017-04-05_13-27-49r.1111.pdf Gudmundsson, A. (2012) Mechanical aspects of postglacial volcanism and tectonics of the Reykjanes Peninsula, southwest Iceland. Journal of Geophysical Research: Solid Earth, 91 (B12). pp. 12711-12721. DOI 10.1029/JB091iB12p12711 <https://doi.org/10.1029/JB091iB12p12711>. doi:10.1029/JB091iB12p12711 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1029/JB091iB12p12711 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
91 |
container_issue |
B12 |
container_start_page |
12711 |
op_container_end_page |
12721 |
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1766042176500793344 |