Melt Generation and Movement beneath Theistareykir, NE Iceland
A detailed study of the volume and composition of all the lavas from the Theistareykir segment of the Northern Volcanic Zone of Iceland was designed to study basaltic melt generation and movement beneath a spreading ridge. The trace element compositions of the lavas are variable, and those of melt i...
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2001
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fthighwire:oai:open-archive.highwire.org:petrology:42/2/321 2023-05-15T16:47:35+02:00 Melt Generation and Movement beneath Theistareykir, NE Iceland SLATER, LUCY McKENZIE, DAN GRÖNVOLD, KARL SHIMIZU, NOBU 2001-02-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/42/2/321 https://doi.org/10.1093/petrology/42.2.321 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/42/2/321 http://dx.doi.org/10.1093/petrology/42.2.321 Copyright (C) 2001, Oxford University Press ARTICLES TEXT 2001 fthighwire https://doi.org/10.1093/petrology/42.2.321 2013-05-27T16:33:47Z A detailed study of the volume and composition of all the lavas from the Theistareykir segment of the Northern Volcanic Zone of Iceland was designed to study basaltic melt generation and movement beneath a spreading ridge. The trace element compositions of the lavas are variable, and those of melt inclusions in olivine, clinopyroxene and plagioclase phenocrysts even more so. We show that this variability can be produced by mixing instantaneous melts produced by isentropic decompression of mantle whose initial potential temperature is 1480°C, and that the calculated volume and composition of the average melt is consistent with geophysical and petrological observations. Pressure and temperature estimates suggest that the phenocrysts form in the upper mantle, at depths of 30–40 km, and trap melts formed at greater depths. Some mixing of the instantaneous melts occurs before the melt is trapped, and more mixing occurs before the lavas are erupted. A similar model can account for the composition of melt inclusions from the FAMOUS area of the Mid-Atlantic Ridge, and from the Gorda and Juan de Fuca Ridges. Text Iceland HighWire Press (Stanford University) Mid-Atlantic Ridge Journal of Petrology 42 2 321 354 |
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HighWire Press (Stanford University) |
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language |
English |
topic |
ARTICLES |
spellingShingle |
ARTICLES SLATER, LUCY McKENZIE, DAN GRÖNVOLD, KARL SHIMIZU, NOBU Melt Generation and Movement beneath Theistareykir, NE Iceland |
topic_facet |
ARTICLES |
description |
A detailed study of the volume and composition of all the lavas from the Theistareykir segment of the Northern Volcanic Zone of Iceland was designed to study basaltic melt generation and movement beneath a spreading ridge. The trace element compositions of the lavas are variable, and those of melt inclusions in olivine, clinopyroxene and plagioclase phenocrysts even more so. We show that this variability can be produced by mixing instantaneous melts produced by isentropic decompression of mantle whose initial potential temperature is 1480°C, and that the calculated volume and composition of the average melt is consistent with geophysical and petrological observations. Pressure and temperature estimates suggest that the phenocrysts form in the upper mantle, at depths of 30–40 km, and trap melts formed at greater depths. Some mixing of the instantaneous melts occurs before the melt is trapped, and more mixing occurs before the lavas are erupted. A similar model can account for the composition of melt inclusions from the FAMOUS area of the Mid-Atlantic Ridge, and from the Gorda and Juan de Fuca Ridges. |
format |
Text |
author |
SLATER, LUCY McKENZIE, DAN GRÖNVOLD, KARL SHIMIZU, NOBU |
author_facet |
SLATER, LUCY McKENZIE, DAN GRÖNVOLD, KARL SHIMIZU, NOBU |
author_sort |
SLATER, LUCY |
title |
Melt Generation and Movement beneath Theistareykir, NE Iceland |
title_short |
Melt Generation and Movement beneath Theistareykir, NE Iceland |
title_full |
Melt Generation and Movement beneath Theistareykir, NE Iceland |
title_fullStr |
Melt Generation and Movement beneath Theistareykir, NE Iceland |
title_full_unstemmed |
Melt Generation and Movement beneath Theistareykir, NE Iceland |
title_sort |
melt generation and movement beneath theistareykir, ne iceland |
publisher |
Oxford University Press |
publishDate |
2001 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/42/2/321 https://doi.org/10.1093/petrology/42.2.321 |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/42/2/321 http://dx.doi.org/10.1093/petrology/42.2.321 |
op_rights |
Copyright (C) 2001, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/42.2.321 |
container_title |
Journal of Petrology |
container_volume |
42 |
container_issue |
2 |
container_start_page |
321 |
op_container_end_page |
354 |
_version_ |
1766037682532646912 |