Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec
The Cape Smith volcanic fold belt extends across the Ungava Peninsula of Quebec, and is part of the Aphebian Circum-Ungava geosyncline. The contact with the Superior Province to the south is an unconformity, but the relationship with gneisses to the north has been obscured by Proterozoic metamorphis...
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1983
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crcansciencepubl:10.1139/e83-072 2024-09-15T18:40:03+00:00 Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec Doig, Ronald 1983 http://dx.doi.org/10.1139/e83-072 http://www.nrcresearchpress.com/doi/pdf/10.1139/e83-072 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 20, issue 5, page 821-829 ISSN 0008-4077 1480-3313 journal-article 1983 crcansciencepubl https://doi.org/10.1139/e83-072 2024-07-25T04:10:08Z The Cape Smith volcanic fold belt extends across the Ungava Peninsula of Quebec, and is part of the Aphebian Circum-Ungava geosyncline. The contact with the Superior Province to the south is an unconformity, but the relationship with gneisses to the north has been obscured by Proterozoic metamorphism and deformation. Rb–Sr isochrons obtained from these gneisses yield ages ranging from 2934 to 2569 Ma, in part a result of the scale of sampling. Units interpreted to be granitic intrusions and migmatites yield ages of about 2750 Ma. All initial ratios are low (0.701–0.703) but seem to define an evolutionary path consistent with generation by melting of sialic crust with a Rb/Sr ratio of 0.14.Dominantly quartz-rich metasediments occur throughout the area of reworked Archean gneisses, and are tentatively considered to be temporally equivalent to the Proterozoic Cape Smith fold belt rocks.The simplest evolutionary model for this part of the Circum-Ungava belt would consist of a deep Proterozoic sedimentary basin to the north deposited on and deformed with Archean crust. The Cape Smith rocks would represent in part rift-related volcanism at the margin of the basin. There is no requirement for the opening of a broad ocean or for a suture between colliding Archean cratons. Article in Journal/Newspaper Ungava peninsula Smith Rocks Canadian Science Publishing Canadian Journal of Earth Sciences 20 5 821 829 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
description |
The Cape Smith volcanic fold belt extends across the Ungava Peninsula of Quebec, and is part of the Aphebian Circum-Ungava geosyncline. The contact with the Superior Province to the south is an unconformity, but the relationship with gneisses to the north has been obscured by Proterozoic metamorphism and deformation. Rb–Sr isochrons obtained from these gneisses yield ages ranging from 2934 to 2569 Ma, in part a result of the scale of sampling. Units interpreted to be granitic intrusions and migmatites yield ages of about 2750 Ma. All initial ratios are low (0.701–0.703) but seem to define an evolutionary path consistent with generation by melting of sialic crust with a Rb/Sr ratio of 0.14.Dominantly quartz-rich metasediments occur throughout the area of reworked Archean gneisses, and are tentatively considered to be temporally equivalent to the Proterozoic Cape Smith fold belt rocks.The simplest evolutionary model for this part of the Circum-Ungava belt would consist of a deep Proterozoic sedimentary basin to the north deposited on and deformed with Archean crust. The Cape Smith rocks would represent in part rift-related volcanism at the margin of the basin. There is no requirement for the opening of a broad ocean or for a suture between colliding Archean cratons. |
format |
Article in Journal/Newspaper |
author |
Doig, Ronald |
spellingShingle |
Doig, Ronald Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
author_facet |
Doig, Ronald |
author_sort |
Doig, Ronald |
title |
Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
title_short |
Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
title_full |
Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
title_fullStr |
Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
title_full_unstemmed |
Rb–Sr isotopic study of Archean gneisses north of the Cape Smith fold belt, Ungava, Quebec |
title_sort |
rb–sr isotopic study of archean gneisses north of the cape smith fold belt, ungava, quebec |
publisher |
Canadian Science Publishing |
publishDate |
1983 |
url |
http://dx.doi.org/10.1139/e83-072 http://www.nrcresearchpress.com/doi/pdf/10.1139/e83-072 |
genre |
Ungava peninsula Smith Rocks |
genre_facet |
Ungava peninsula Smith Rocks |
op_source |
Canadian Journal of Earth Sciences volume 20, issue 5, page 821-829 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e83-072 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
20 |
container_issue |
5 |
container_start_page |
821 |
op_container_end_page |
829 |
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1810484365568770048 |