K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications
Over 20 K–Ar ages and one 40 Ar/ 39 Ar incremental heating analysis of amphiboles from the Bay of Islands ophiolite complex and the Little Port Complex, western Newfoundland, are reported. Amphiboles were obtained from granitic rocks and amphibolites which outcrop in the northern part of the Little...
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Canadian Science Publishing
1976
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Online Access: | http://dx.doi.org/10.1139/e76-055 http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-055 |
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crcansciencepubl:10.1139/e76-055 2024-09-15T18:19:54+00:00 K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications Archibald, D. A. Farrar, E. 1976 http://dx.doi.org/10.1139/e76-055 http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-055 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 13, issue 4, page 520-529 ISSN 0008-4077 1480-3313 journal-article 1976 crcansciencepubl https://doi.org/10.1139/e76-055 2024-07-25T04:10:06Z Over 20 K–Ar ages and one 40 Ar/ 39 Ar incremental heating analysis of amphiboles from the Bay of Islands ophiolite complex and the Little Port Complex, western Newfoundland, are reported. Amphiboles were obtained from granitic rocks and amphibolites which outcrop in the northern part of the Little Port Complex, and from the sheeted dykes and gabbros and from the basal metamorphic aureole of the ophiolite. The results indicate that obduction of the ophiolite took place approximately 470 m.y. ago and that movement, associated with the emplacement of the Humber Arm allochthon, ceased after 455 m.y. BP. It is postulated that initial argon in amphiboles taken from the basal metamorphic aureole of the ophiolite has resulted in some anomalously high ages.Since the stratigraphic and paleontological relationships in the Bay of Islands are are well known, the dates for obduction and final movement represent additional geochronological reference points in the lower to middle Ordovician time scale. Article in Journal/Newspaper Newfoundland Canadian Science Publishing Canadian Journal of Earth Sciences 13 4 520 529 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Over 20 K–Ar ages and one 40 Ar/ 39 Ar incremental heating analysis of amphiboles from the Bay of Islands ophiolite complex and the Little Port Complex, western Newfoundland, are reported. Amphiboles were obtained from granitic rocks and amphibolites which outcrop in the northern part of the Little Port Complex, and from the sheeted dykes and gabbros and from the basal metamorphic aureole of the ophiolite. The results indicate that obduction of the ophiolite took place approximately 470 m.y. ago and that movement, associated with the emplacement of the Humber Arm allochthon, ceased after 455 m.y. BP. It is postulated that initial argon in amphiboles taken from the basal metamorphic aureole of the ophiolite has resulted in some anomalously high ages.Since the stratigraphic and paleontological relationships in the Bay of Islands are are well known, the dates for obduction and final movement represent additional geochronological reference points in the lower to middle Ordovician time scale. |
format |
Article in Journal/Newspaper |
author |
Archibald, D. A. Farrar, E. |
spellingShingle |
Archibald, D. A. Farrar, E. K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
author_facet |
Archibald, D. A. Farrar, E. |
author_sort |
Archibald, D. A. |
title |
K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
title_short |
K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
title_full |
K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
title_fullStr |
K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
title_full_unstemmed |
K–Ar ages of amphiboles from the Bay of Islands ophiolite and the Little Port Complex, western Newfoundland, and their geological implications |
title_sort |
k–ar ages of amphiboles from the bay of islands ophiolite and the little port complex, western newfoundland, and their geological implications |
publisher |
Canadian Science Publishing |
publishDate |
1976 |
url |
http://dx.doi.org/10.1139/e76-055 http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-055 |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 13, issue 4, page 520-529 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e76-055 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
13 |
container_issue |
4 |
container_start_page |
520 |
op_container_end_page |
529 |
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1810458264462163968 |