Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data
A Nd isotopic study was carried out on 1.9−1.8 Ga rocks from two parts of the Trans-Hudson Orogen in northern Canada. The first part is the Reindeer Lake Zone in the Churchill Province in Saskatchewan, where a variety of volcanic, granitoid, and sedimentary rocks are preserved in several lithotecton...
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1987
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crcansciencepubl:10.1139/e87-042 2024-04-28T08:14:27+00:00 Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data Chauvel, C. Arndt, N. T. Kielinzcuk, S. Thom, A. 1987 http://dx.doi.org/10.1139/e87-042 http://www.nrcresearchpress.com/doi/pdf/10.1139/e87-042 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 24, issue 3, page 396-406 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1987 crcansciencepubl https://doi.org/10.1139/e87-042 2024-04-09T06:56:31Z A Nd isotopic study was carried out on 1.9−1.8 Ga rocks from two parts of the Trans-Hudson Orogen in northern Canada. The first part is the Reindeer Lake Zone in the Churchill Province in Saskatchewan, where a variety of volcanic, granitoid, and sedimentary rocks are preserved in several lithotectonic belts that border a reworked Archean craton to the northwest. The second area comprises the Ottawa and Belcher islands, in Hudson Bay, and the Fox River volcanics, in Manitoba. These form part of the Circum-Superior Belt, a band of basaltic volcanics and sedimentary rocks that overlies the Archean Superior craton.From U–Pb zircon ages, Pb–Pb ages, and Sm–Nd ages, Nd initial isotopic compositions were calculated for all analyzed samples. In the Saskatchewan terrains, we obtained a large range of ε Nd values, from +5 to −8. The highest values (+4 to +5) come from two volcanic-dominated belts (Flin Flon and Western la Ronge), lower values (~+2) characterize intervening sediment-dominated domains (Eastern La Ronge, Glennie Lake, and Kisseynew), and still lower values (−1 to −4) were found in migmatitic and granitoid belts adjacent to the reworked Archean craton in the northwest. Each lithotectonic belt has its own characteristic, restricted range of ε Nd values, and, with few exceptions, there is no correlation between ε Nd and rock type; i.e., in individual belts, volcanics, granites, and sediments have very similar ε Nd values.In the Circum-Superior Belt, three lava flows from the Ottawa Islands have ε Nd values ranging from +4.5 to 0, and samples from the Belcher Islands have values ranging from +3.5 to −9.These results are explained by mixing between mantle-derived rocks and variable amounts of Archean continental crustal rocks. Assuming that 1.9 Ga ago the mantle had an ε Nd value of +5 and Archean crust had an ε Nd value of −12, we calculate proportions of Archean crustal material in Trans-Hudson rocks ranging from ~2 to 35 %, increasing systematically toward the Archean platform. The mean Archean component is ... Article in Journal/Newspaper Belcher Islands Churchill Hudson Bay Ottawa Islands Reindeer Lake Canadian Science Publishing Canadian Journal of Earth Sciences 24 3 396 406 |
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Canadian Science Publishing |
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General Earth and Planetary Sciences |
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General Earth and Planetary Sciences Chauvel, C. Arndt, N. T. Kielinzcuk, S. Thom, A. Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
topic_facet |
General Earth and Planetary Sciences |
description |
A Nd isotopic study was carried out on 1.9−1.8 Ga rocks from two parts of the Trans-Hudson Orogen in northern Canada. The first part is the Reindeer Lake Zone in the Churchill Province in Saskatchewan, where a variety of volcanic, granitoid, and sedimentary rocks are preserved in several lithotectonic belts that border a reworked Archean craton to the northwest. The second area comprises the Ottawa and Belcher islands, in Hudson Bay, and the Fox River volcanics, in Manitoba. These form part of the Circum-Superior Belt, a band of basaltic volcanics and sedimentary rocks that overlies the Archean Superior craton.From U–Pb zircon ages, Pb–Pb ages, and Sm–Nd ages, Nd initial isotopic compositions were calculated for all analyzed samples. In the Saskatchewan terrains, we obtained a large range of ε Nd values, from +5 to −8. The highest values (+4 to +5) come from two volcanic-dominated belts (Flin Flon and Western la Ronge), lower values (~+2) characterize intervening sediment-dominated domains (Eastern La Ronge, Glennie Lake, and Kisseynew), and still lower values (−1 to −4) were found in migmatitic and granitoid belts adjacent to the reworked Archean craton in the northwest. Each lithotectonic belt has its own characteristic, restricted range of ε Nd values, and, with few exceptions, there is no correlation between ε Nd and rock type; i.e., in individual belts, volcanics, granites, and sediments have very similar ε Nd values.In the Circum-Superior Belt, three lava flows from the Ottawa Islands have ε Nd values ranging from +4.5 to 0, and samples from the Belcher Islands have values ranging from +3.5 to −9.These results are explained by mixing between mantle-derived rocks and variable amounts of Archean continental crustal rocks. Assuming that 1.9 Ga ago the mantle had an ε Nd value of +5 and Archean crust had an ε Nd value of −12, we calculate proportions of Archean crustal material in Trans-Hudson rocks ranging from ~2 to 35 %, increasing systematically toward the Archean platform. The mean Archean component is ... |
format |
Article in Journal/Newspaper |
author |
Chauvel, C. Arndt, N. T. Kielinzcuk, S. Thom, A. |
author_facet |
Chauvel, C. Arndt, N. T. Kielinzcuk, S. Thom, A. |
author_sort |
Chauvel, C. |
title |
Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
title_short |
Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
title_full |
Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
title_fullStr |
Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
title_full_unstemmed |
Formation of Canadian 1.9 Ga old continental crust. I: Nd isotopic data |
title_sort |
formation of canadian 1.9 ga old continental crust. i: nd isotopic data |
publisher |
Canadian Science Publishing |
publishDate |
1987 |
url |
http://dx.doi.org/10.1139/e87-042 http://www.nrcresearchpress.com/doi/pdf/10.1139/e87-042 |
genre |
Belcher Islands Churchill Hudson Bay Ottawa Islands Reindeer Lake |
genre_facet |
Belcher Islands Churchill Hudson Bay Ottawa Islands Reindeer Lake |
op_source |
Canadian Journal of Earth Sciences volume 24, issue 3, page 396-406 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e87-042 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
24 |
container_issue |
3 |
container_start_page |
396 |
op_container_end_page |
406 |
_version_ |
1797580500048543744 |