40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic
At the submerged margins of the North Atlantic, andesitic to dacitic and basaltic volcanic rocks occur together. The silicic rocks were derived by processes requiring the presence of continental crust (crustal anatexis and/or contamination of mafic magmas) while the majority of the basaltic lavas ha...
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1998
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Online Access: | http://dx.doi.org/10.1017/s0016756898008401 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756898008401 |
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crcambridgeupr:10.1017/s0016756898008401 2024-04-07T07:52:49+00:00 40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic SINTON, C. W. HITCHEN, K. DUNCAN, R. A. 1998 http://dx.doi.org/10.1017/s0016756898008401 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756898008401 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 135, issue 2, page 161-170 ISSN 0016-7568 1469-5081 Geology journal-article 1998 crcambridgeupr https://doi.org/10.1017/s0016756898008401 2024-03-08T00:34:15Z At the submerged margins of the North Atlantic, andesitic to dacitic and basaltic volcanic rocks occur together. The silicic rocks were derived by processes requiring the presence of continental crust (crustal anatexis and/or contamination of mafic magmas) while the majority of the basaltic lavas had little or no contact with continental crust. We report 40 Ar– 39 Ar incremental heating ages for several dacitic and basaltic rocks recovered from three offshore localities of the North Atlantic Igneous Province. Dacitic lavas and tuffs at the southeast Greenland margin and trachytic lavas in the Scottish Hebrides erupted contemporaneously with basaltic lavas at 62–61 Ma. In contrast, the silicic lavas from the northern Rockall Trough (offshore western Scotland) and the Vøring Plateau (offshore Norway) erupted at ∼55 Ma followed shortly by basaltic volcanism. At this time, silicic magmatism at the southeast Greenland margin had ceased and only oceanic basalts were erupted. Similarly, ∼55 Ma lavas on the southwest Rockall Plateau are wholly basaltic. The compositions of all of the dated silicic volcanic rocks are consistent with derivation from partial melting of either continental crust or sediments. The heat necessary for partial melting appears to have been provided by basaltic magmas. Therefore, the existence of the silicic rocks indicates the presence of continental crust as well as a stable tectonic environment that allowed the stagnation and pooling of basaltic melts within the crust. With this in mind, it is apparent that at 62–60 Ma, both western and eastern sides of the present North Atlantic margins were characterized by extensional environments within continental crust that were restrictive to the passage of mafic magmas. By 55 Ma, at the time of continental breakup, the proximal margins at southeast Greenland and the Rockall Plateau were devoid of continental crust. But the presence of 55 Ma silicic magmatism on the eastern North Atlantic margin can be attributed to a broader zone of magmatism and ... Article in Journal/Newspaper Greenland North Atlantic Cambridge University Press Greenland Norway Rockall Trough ENVELOPE(-15.036,-15.036,53.825,53.825) Vøring Plateau ENVELOPE(4.000,4.000,67.000,67.000) Rockall Plateau ENVELOPE(-18.833,-18.833,56.333,56.333) Geological Magazine 135 2 161 170 |
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Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Geology |
spellingShingle |
Geology SINTON, C. W. HITCHEN, K. DUNCAN, R. A. 40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
topic_facet |
Geology |
description |
At the submerged margins of the North Atlantic, andesitic to dacitic and basaltic volcanic rocks occur together. The silicic rocks were derived by processes requiring the presence of continental crust (crustal anatexis and/or contamination of mafic magmas) while the majority of the basaltic lavas had little or no contact with continental crust. We report 40 Ar– 39 Ar incremental heating ages for several dacitic and basaltic rocks recovered from three offshore localities of the North Atlantic Igneous Province. Dacitic lavas and tuffs at the southeast Greenland margin and trachytic lavas in the Scottish Hebrides erupted contemporaneously with basaltic lavas at 62–61 Ma. In contrast, the silicic lavas from the northern Rockall Trough (offshore western Scotland) and the Vøring Plateau (offshore Norway) erupted at ∼55 Ma followed shortly by basaltic volcanism. At this time, silicic magmatism at the southeast Greenland margin had ceased and only oceanic basalts were erupted. Similarly, ∼55 Ma lavas on the southwest Rockall Plateau are wholly basaltic. The compositions of all of the dated silicic volcanic rocks are consistent with derivation from partial melting of either continental crust or sediments. The heat necessary for partial melting appears to have been provided by basaltic magmas. Therefore, the existence of the silicic rocks indicates the presence of continental crust as well as a stable tectonic environment that allowed the stagnation and pooling of basaltic melts within the crust. With this in mind, it is apparent that at 62–60 Ma, both western and eastern sides of the present North Atlantic margins were characterized by extensional environments within continental crust that were restrictive to the passage of mafic magmas. By 55 Ma, at the time of continental breakup, the proximal margins at southeast Greenland and the Rockall Plateau were devoid of continental crust. But the presence of 55 Ma silicic magmatism on the eastern North Atlantic margin can be attributed to a broader zone of magmatism and ... |
format |
Article in Journal/Newspaper |
author |
SINTON, C. W. HITCHEN, K. DUNCAN, R. A. |
author_facet |
SINTON, C. W. HITCHEN, K. DUNCAN, R. A. |
author_sort |
SINTON, C. W. |
title |
40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
title_short |
40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
title_full |
40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
title_fullStr |
40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
title_full_unstemmed |
40 Ar– 39 Ar geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic |
title_sort |
40 ar– 39 ar geochronology of silicic and basic volcanic rocks on the margins of the north atlantic |
publisher |
Cambridge University Press (CUP) |
publishDate |
1998 |
url |
http://dx.doi.org/10.1017/s0016756898008401 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756898008401 |
long_lat |
ENVELOPE(-15.036,-15.036,53.825,53.825) ENVELOPE(4.000,4.000,67.000,67.000) ENVELOPE(-18.833,-18.833,56.333,56.333) |
geographic |
Greenland Norway Rockall Trough Vøring Plateau Rockall Plateau |
geographic_facet |
Greenland Norway Rockall Trough Vøring Plateau Rockall Plateau |
genre |
Greenland North Atlantic |
genre_facet |
Greenland North Atlantic |
op_source |
Geological Magazine volume 135, issue 2, page 161-170 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756898008401 |
container_title |
Geological Magazine |
container_volume |
135 |
container_issue |
2 |
container_start_page |
161 |
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170 |
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1795668317077241856 |