Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination
Silurian to Devonian granites within the Gander Zone of the Appalachian Central Mobile Belt in northeastern Newfoundland formed adjacent to the former Gondwanan continental margin following terminal closure of the Iapetus Ocean. Comparison of geochemical and isotopic characteristics of the granites...
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Online Access: | http://dx.doi.org/10.1139/e99-116 http://www.nrcresearchpress.com/doi/pdf/10.1139/e99-116 |
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crcansciencepubl:10.1139/e99-116 2024-09-15T18:19:55+00:00 Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination Schofield, David I D'Lemos, Richard S 2000 http://dx.doi.org/10.1139/e99-116 http://www.nrcresearchpress.com/doi/pdf/10.1139/e99-116 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 37, issue 4, page 535-547 ISSN 0008-4077 1480-3313 journal-article 2000 crcansciencepubl https://doi.org/10.1139/e99-116 2024-08-01T04:10:00Z Silurian to Devonian granites within the Gander Zone of the Appalachian Central Mobile Belt in northeastern Newfoundland formed adjacent to the former Gondwanan continental margin following terminal closure of the Iapetus Ocean. Comparison of geochemical and isotopic characteristics of the granites with their host migmatites and metasediments, amphibolite, and orthogneiss constrain their potential source. Nd and Sr isotopic compositions indicate that no single source or binary mixing product could have produced the granites. Instead, we show that they result from multicomponent mixing involving a contribution from unexposed crystalline basement, mantle or underplate, and variable contamination by supracrustal host rocks. The timing and composition of granite magmatism do not exhibit collisional orogenic, subduction-related, or continental rifting characteristics. Hence, we relate magmatism to lithospheric melting following delamination of an orogenic keel. This process provides the influx of mantle-derived magma into fertile crust and hence promotes lower crustal melting and primary magma mixing. Article in Journal/Newspaper Newfoundland Canadian Science Publishing Canadian Journal of Earth Sciences 37 4 535 547 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Silurian to Devonian granites within the Gander Zone of the Appalachian Central Mobile Belt in northeastern Newfoundland formed adjacent to the former Gondwanan continental margin following terminal closure of the Iapetus Ocean. Comparison of geochemical and isotopic characteristics of the granites with their host migmatites and metasediments, amphibolite, and orthogneiss constrain their potential source. Nd and Sr isotopic compositions indicate that no single source or binary mixing product could have produced the granites. Instead, we show that they result from multicomponent mixing involving a contribution from unexposed crystalline basement, mantle or underplate, and variable contamination by supracrustal host rocks. The timing and composition of granite magmatism do not exhibit collisional orogenic, subduction-related, or continental rifting characteristics. Hence, we relate magmatism to lithospheric melting following delamination of an orogenic keel. This process provides the influx of mantle-derived magma into fertile crust and hence promotes lower crustal melting and primary magma mixing. |
format |
Article in Journal/Newspaper |
author |
Schofield, David I D'Lemos, Richard S |
spellingShingle |
Schofield, David I D'Lemos, Richard S Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
author_facet |
Schofield, David I D'Lemos, Richard S |
author_sort |
Schofield, David I |
title |
Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
title_short |
Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
title_full |
Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
title_fullStr |
Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
title_full_unstemmed |
Granite petrogenesis in the Gander Zone, NE Newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
title_sort |
granite petrogenesis in the gander zone, ne newfoundland: mixing of melts from multiple sources and the role of lithospheric delamination |
publisher |
Canadian Science Publishing |
publishDate |
2000 |
url |
http://dx.doi.org/10.1139/e99-116 http://www.nrcresearchpress.com/doi/pdf/10.1139/e99-116 |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 37, issue 4, page 535-547 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e99-116 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
37 |
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4 |
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535 |
op_container_end_page |
547 |
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1810458269357965312 |