Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield
Massif-type anorthosites occur worldwide and were predominantly formed during the Paleo- to Mesoproterozoic Era, with an exceptionally large number emplaced in southeastern Laurentia, both within the Grenville Province and in the foreland of the Southeastern Churchill Province and North Atlantic Cra...
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2024
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crcansciencepubl:10.1139/cjes-2024-0021 2024-06-23T07:55:10+00:00 Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield Corrigan, David 2024 http://dx.doi.org/10.1139/cjes-2024-0021 https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2024-0021 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0021 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences ISSN 0008-4077 1480-3313 journal-article 2024 crcansciencepubl https://doi.org/10.1139/cjes-2024-0021 2024-06-13T04:10:49Z Massif-type anorthosites occur worldwide and were predominantly formed during the Paleo- to Mesoproterozoic Era, with an exceptionally large number emplaced in southeastern Laurentia, both within the Grenville Province and in the foreland of the Southeastern Churchill Province and North Atlantic Craton (Nain Province). Their secular nature infers that physical and chemical conditions necessary for their formation were optimized during that time period. A review of geochronological and ambient tectonic regimes that were operating during their emplacement suggests that they formed during four periods, ca. 1.65 Ga, ca. 1.45–1.30 Ga, ca. 1.16–1.14 Ga, and 1.08–1.01 Ga. The first two pulses overlap with continent–ocean convergence and subduction beneath the SE Laurentian margin. The last two pulses correlate with continent–continent collisional tectonics. We argue that higher mantle temperatures during the Proterozoic, as inferred in published models, were not sufficient, by themselves, to produce the necessary volume of basaltic underplate—a key factor in the generation of massif-type anorthosites—and that mantle re-fertilization through metasomatism and/or lateral accretion of oceanic lithosphere might have played a key role. High geothermal gradients acquired during the 2.0–1.2 Ga accretionary and continental arc phase may have helped sustain abnormally high temperatures during the 1.2–1.0 Ga collisional phase of the Grenville Province. Article in Journal/Newspaper North Atlantic Canadian Science Publishing Nain ENVELOPE(-61.695,-61.695,56.542,56.542) Canadian Journal of Earth Sciences |
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Open Polar |
collection |
Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Massif-type anorthosites occur worldwide and were predominantly formed during the Paleo- to Mesoproterozoic Era, with an exceptionally large number emplaced in southeastern Laurentia, both within the Grenville Province and in the foreland of the Southeastern Churchill Province and North Atlantic Craton (Nain Province). Their secular nature infers that physical and chemical conditions necessary for their formation were optimized during that time period. A review of geochronological and ambient tectonic regimes that were operating during their emplacement suggests that they formed during four periods, ca. 1.65 Ga, ca. 1.45–1.30 Ga, ca. 1.16–1.14 Ga, and 1.08–1.01 Ga. The first two pulses overlap with continent–ocean convergence and subduction beneath the SE Laurentian margin. The last two pulses correlate with continent–continent collisional tectonics. We argue that higher mantle temperatures during the Proterozoic, as inferred in published models, were not sufficient, by themselves, to produce the necessary volume of basaltic underplate—a key factor in the generation of massif-type anorthosites—and that mantle re-fertilization through metasomatism and/or lateral accretion of oceanic lithosphere might have played a key role. High geothermal gradients acquired during the 2.0–1.2 Ga accretionary and continental arc phase may have helped sustain abnormally high temperatures during the 1.2–1.0 Ga collisional phase of the Grenville Province. |
format |
Article in Journal/Newspaper |
author |
Corrigan, David |
spellingShingle |
Corrigan, David Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
author_facet |
Corrigan, David |
author_sort |
Corrigan, David |
title |
Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
title_short |
Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
title_full |
Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
title_fullStr |
Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
title_full_unstemmed |
Geodynamic setting of Proterozoic massif-type anorthosites in the Eastern Canadian Shield |
title_sort |
geodynamic setting of proterozoic massif-type anorthosites in the eastern canadian shield |
publisher |
Canadian Science Publishing |
publishDate |
2024 |
url |
http://dx.doi.org/10.1139/cjes-2024-0021 https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2024-0021 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0021 |
long_lat |
ENVELOPE(-61.695,-61.695,56.542,56.542) |
geographic |
Nain |
geographic_facet |
Nain |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Canadian Journal of Earth Sciences ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjes-2024-0021 |
container_title |
Canadian Journal of Earth Sciences |
_version_ |
1802647630875983872 |