Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland
SUMMARY The ‘Maelifell caldera’ is the name given to a separate collapse area situated on the southern margin of the main caldera of the Tertiary Alftafjordur volcano. It is 2 km in diameter and is made up of inward dipping welded tuffs, agglomerate (including patches of welded agglomerate), tufface...
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Cambridge University Press (CUP)
1969
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Online Access: | http://dx.doi.org/10.1017/s0016756800059306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800059306 |
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crcambridgeupr:10.1017/s0016756800059306 2024-09-15T18:14:00+00:00 Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland Blake, D. H. 1969 http://dx.doi.org/10.1017/s0016756800059306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800059306 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 106, issue 6, page 531-541 ISSN 0016-7568 1469-5081 journal-article 1969 crcambridgeupr https://doi.org/10.1017/s0016756800059306 2024-07-31T04:04:20Z SUMMARY The ‘Maelifell caldera’ is the name given to a separate collapse area situated on the southern margin of the main caldera of the Tertiary Alftafjordur volcano. It is 2 km in diameter and is made up of inward dipping welded tuffs, agglomerate (including patches of welded agglomerate), tuffaceous sediments and rhyolite and andesite lavas. The welded tuffs occur as thin pitchstone sheets and as much thicker felsitic masses: the former contain inclusions of basalt glass and are good examples of the simultaneous eruption of acid and basic magmas. It is suggested that the caldera represents the core of a parasitic volcano, beneath which there was a high level acid magma chamber, the immediate source of the local acid rocks. The magma chamber was intersected by numerous intrusions of basic magma, and these caused explosive eruptions and the emission of acid and basic magma to form thin pitchstone sheets. Decreased pressure in the magma chamber after eruptions caused repeated collapse within the cal Article in Journal/Newspaper Iceland Cambridge University Press Geological Magazine 106 6 531 541 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
SUMMARY The ‘Maelifell caldera’ is the name given to a separate collapse area situated on the southern margin of the main caldera of the Tertiary Alftafjordur volcano. It is 2 km in diameter and is made up of inward dipping welded tuffs, agglomerate (including patches of welded agglomerate), tuffaceous sediments and rhyolite and andesite lavas. The welded tuffs occur as thin pitchstone sheets and as much thicker felsitic masses: the former contain inclusions of basalt glass and are good examples of the simultaneous eruption of acid and basic magmas. It is suggested that the caldera represents the core of a parasitic volcano, beneath which there was a high level acid magma chamber, the immediate source of the local acid rocks. The magma chamber was intersected by numerous intrusions of basic magma, and these caused explosive eruptions and the emission of acid and basic magma to form thin pitchstone sheets. Decreased pressure in the magma chamber after eruptions caused repeated collapse within the cal |
format |
Article in Journal/Newspaper |
author |
Blake, D. H. |
spellingShingle |
Blake, D. H. Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
author_facet |
Blake, D. H. |
author_sort |
Blake, D. H. |
title |
Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
title_short |
Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
title_full |
Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
title_fullStr |
Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
title_full_unstemmed |
Welded tuffs and the Maelifell caldera, Alftafjordur volcano, south-eastern Iceland |
title_sort |
welded tuffs and the maelifell caldera, alftafjordur volcano, south-eastern iceland |
publisher |
Cambridge University Press (CUP) |
publishDate |
1969 |
url |
http://dx.doi.org/10.1017/s0016756800059306 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800059306 |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Geological Magazine volume 106, issue 6, page 531-541 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756800059306 |
container_title |
Geological Magazine |
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106 |
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6 |
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531 |
op_container_end_page |
541 |
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1810451788023726080 |