Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland
A gravity survey was carried out to study the structure and geometry of craters and underlying diatremes formed in two major explosive basaltic fissure eruptions, the ~60 km long AD 871±2 Vatnaöldur and AD ~1477 Veiðivötn fissures in South Central Iceland, both belonging to the Bárðarbunga-Veiðivötn...
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ftskemman:oai:skemman.is:1946/15937 2023-05-15T16:49:10+02:00 Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland Giniaux, Jeanne M., 1989- Háskóli Íslands 2013-06 application/pdf http://hdl.handle.net/1946/15937 en eng http://hdl.handle.net/1946/15937 Jarðfræði Veiðivötn Vatnaöldur Gígar Eldgos Thesis Master's 2013 ftskemman 2022-12-11T06:59:43Z A gravity survey was carried out to study the structure and geometry of craters and underlying diatremes formed in two major explosive basaltic fissure eruptions, the ~60 km long AD 871±2 Vatnaöldur and AD ~1477 Veiðivötn fissures in South Central Iceland, both belonging to the Bárðarbunga-Veiðivötn volcanic system. A minor effusive phase at the end of the Veiðivötn eruption filled the bottom of the large phreatomagmatic craters from the main explosive phase, while the Vatnaöldur eruption was almost purely explosive. Six gravity profiles were surveyed across six explosive craters, using a LaCoste&Romberg gravimeter and kinematic GPS. Complete Bouguer anomalies were obtained by integrating the gravitational effects of the mass of the topography using a high-resolution DEM. Studies of the subsurface geometry and structures were made using 2.5-D forward gravity models. The results indicate 100-300 m deep diatreme structures at both Vatnaöldur and Veiðivötn. The purely explosive edifices at Vatnaöldur Innri are filled with relative low density unconsolidated water-saturated tephra, and have much narrower diatremes than those seen at the Veiðivötn fissure, which experienced a late effusive stage leading to lava-filling of the craters. It is proposed that softer subsurface at Veiðivötn led to wider diatremes than found at Vatnaöldur. At least at one of the craters in Vatnaöldur, the activity may have lasted long enough to lead to minor effusive activity, as a relatively high density body, assumed to be lava, fills the diatreme. Lýst er rannsókn á byggingu gíga og efsta hluta gosrásar í tveimur stórum tætigosum, Vatnaöldugosinu 871±2 og Veiðivatnagosinu ~1477. Báðar gossprungurnar tilheyra eldstöðvakerfi Bárðarbungu. Til að skoða innri gerð gíga og gosrásar voru sex snið mæld með þyngdarmæli, fjögur yfir gíga í Vatnaöldum og tvö yfir gíga í Veiðivötnum. Botn gíganna úr Veiðivatnagosinu er þakinn hrauni sem rann í lok þess. Í Vatnaöldum virðist hafa verið svo til hreint tætigos. Hæð mælistöðva var ákvörðuð með ... Thesis Iceland Skemman (Iceland) Botn ENVELOPE(16.030,16.030,68.179,68.179) Veiðivötn ENVELOPE(-18.798,-18.798,64.120,64.120) Vatnaöldur ENVELOPE(-18.896,-18.896,64.125,64.125) |
institution |
Open Polar |
collection |
Skemman (Iceland) |
op_collection_id |
ftskemman |
language |
English |
topic |
Jarðfræði Veiðivötn Vatnaöldur Gígar Eldgos |
spellingShingle |
Jarðfræði Veiðivötn Vatnaöldur Gígar Eldgos Giniaux, Jeanne M., 1989- Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
topic_facet |
Jarðfræði Veiðivötn Vatnaöldur Gígar Eldgos |
description |
A gravity survey was carried out to study the structure and geometry of craters and underlying diatremes formed in two major explosive basaltic fissure eruptions, the ~60 km long AD 871±2 Vatnaöldur and AD ~1477 Veiðivötn fissures in South Central Iceland, both belonging to the Bárðarbunga-Veiðivötn volcanic system. A minor effusive phase at the end of the Veiðivötn eruption filled the bottom of the large phreatomagmatic craters from the main explosive phase, while the Vatnaöldur eruption was almost purely explosive. Six gravity profiles were surveyed across six explosive craters, using a LaCoste&Romberg gravimeter and kinematic GPS. Complete Bouguer anomalies were obtained by integrating the gravitational effects of the mass of the topography using a high-resolution DEM. Studies of the subsurface geometry and structures were made using 2.5-D forward gravity models. The results indicate 100-300 m deep diatreme structures at both Vatnaöldur and Veiðivötn. The purely explosive edifices at Vatnaöldur Innri are filled with relative low density unconsolidated water-saturated tephra, and have much narrower diatremes than those seen at the Veiðivötn fissure, which experienced a late effusive stage leading to lava-filling of the craters. It is proposed that softer subsurface at Veiðivötn led to wider diatremes than found at Vatnaöldur. At least at one of the craters in Vatnaöldur, the activity may have lasted long enough to lead to minor effusive activity, as a relatively high density body, assumed to be lava, fills the diatreme. Lýst er rannsókn á byggingu gíga og efsta hluta gosrásar í tveimur stórum tætigosum, Vatnaöldugosinu 871±2 og Veiðivatnagosinu ~1477. Báðar gossprungurnar tilheyra eldstöðvakerfi Bárðarbungu. Til að skoða innri gerð gíga og gosrásar voru sex snið mæld með þyngdarmæli, fjögur yfir gíga í Vatnaöldum og tvö yfir gíga í Veiðivötnum. Botn gíganna úr Veiðivatnagosinu er þakinn hrauni sem rann í lok þess. Í Vatnaöldum virðist hafa verið svo til hreint tætigos. Hæð mælistöðva var ákvörðuð með ... |
author2 |
Háskóli Íslands |
format |
Thesis |
author |
Giniaux, Jeanne M., 1989- |
author_facet |
Giniaux, Jeanne M., 1989- |
author_sort |
Giniaux, Jeanne M., 1989- |
title |
Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
title_short |
Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
title_full |
Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
title_fullStr |
Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
title_full_unstemmed |
Gravity studies of the structure of the Vatnaöldur and Veiðivötn crater rows, South Central Iceland |
title_sort |
gravity studies of the structure of the vatnaöldur and veiðivötn crater rows, south central iceland |
publishDate |
2013 |
url |
http://hdl.handle.net/1946/15937 |
long_lat |
ENVELOPE(16.030,16.030,68.179,68.179) ENVELOPE(-18.798,-18.798,64.120,64.120) ENVELOPE(-18.896,-18.896,64.125,64.125) |
geographic |
Botn Veiðivötn Vatnaöldur |
geographic_facet |
Botn Veiðivötn Vatnaöldur |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
http://hdl.handle.net/1946/15937 |
_version_ |
1766039271563591680 |