Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada
The Newfoundland Atlantic margin in Eastern Canada formed through protracted lithospheric extension, subsequent rifting, and ultimately, breakup. Mesozoic-Cenozoic magmatism on and offshore Newfoundland coincided with, and potentially resulted from, the concurrent rifting and breakup. In north-centr...
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crcansciencepubl:10.1139/cjes-2024-0087 2024-09-30T14:38:44+00:00 Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada Sandeman, Hamish A. Peace, Alexander L. 2024 http://dx.doi.org/10.1139/cjes-2024-0087 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0087 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-2024-0087 2024-09-12T04:13:26Z The Newfoundland Atlantic margin in Eastern Canada formed through protracted lithospheric extension, subsequent rifting, and ultimately, breakup. Mesozoic-Cenozoic magmatism on and offshore Newfoundland coincided with, and potentially resulted from, the concurrent rifting and breakup. In north-central Newfoundland, the alkali monzogabbroic Budgell Harbour and Dildo Pond stocks, an accompanying lamprophyre dyke swarm, and a peridotite sill of the Notre Dame Bay Magmatic Province are products of a punctuated alkaline magmatic pulse on the Newfoundland margin at ca. 148 Ma (Jurassic, Tithonian) with contemporaneous with rifting and the formation of offshore petroliferous basins. The stocks comprise coarsely modally layered phlogopite-ilmenite-magnetite-kaersutite olivine gabbro or essexite. The radially disposed lamprophyre dykes are aphyric to ilmenite-magnetite-diopside±olivine±kaersutite±phlogopite porphyritic camptonites containing common feldspathic- and/or carbonate-dominant ocelli. Silica-undersaturated (kirschsteinite), oxidized (esseneite, calderite) and incompatible-element-bearing minerals (barite, kainosite) form paragenetically late, small grains in the groundmass mantling other phases. Mineral chemistry, lithogeochemistry and Nd isotopic data indicate the rocks are similar to ocean island basalt and alkaline lamprophyres and were generated via low degrees of partial melting of a Neoproterozoic, weakly garnetiferous lithospheric mantle source. The intrusions occur along the intersections of broadly northeast-trending, inherited, Appalachian-cycle lithospheric scale faults with a prominent east-west step in the northeast Newfoundland MOHO along the northeast Newfoundland coast. The convergence of inherited structures with the topographic variation of the lithosphere-asthenosphere boundary likely focused decompression melting of the lithospheric mantle driven through distal, edge-driven upwelling associated with continued extension in the northwest Atlantic. Article in Journal/Newspaper Newfoundland Northwest Atlantic Ocean Island Canadian Science Publishing Canada Notre Dame Bay ENVELOPE(-54.998,-54.998,49.750,49.750) Canadian Journal of Earth Sciences |
institution |
Open Polar |
collection |
Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
The Newfoundland Atlantic margin in Eastern Canada formed through protracted lithospheric extension, subsequent rifting, and ultimately, breakup. Mesozoic-Cenozoic magmatism on and offshore Newfoundland coincided with, and potentially resulted from, the concurrent rifting and breakup. In north-central Newfoundland, the alkali monzogabbroic Budgell Harbour and Dildo Pond stocks, an accompanying lamprophyre dyke swarm, and a peridotite sill of the Notre Dame Bay Magmatic Province are products of a punctuated alkaline magmatic pulse on the Newfoundland margin at ca. 148 Ma (Jurassic, Tithonian) with contemporaneous with rifting and the formation of offshore petroliferous basins. The stocks comprise coarsely modally layered phlogopite-ilmenite-magnetite-kaersutite olivine gabbro or essexite. The radially disposed lamprophyre dykes are aphyric to ilmenite-magnetite-diopside±olivine±kaersutite±phlogopite porphyritic camptonites containing common feldspathic- and/or carbonate-dominant ocelli. Silica-undersaturated (kirschsteinite), oxidized (esseneite, calderite) and incompatible-element-bearing minerals (barite, kainosite) form paragenetically late, small grains in the groundmass mantling other phases. Mineral chemistry, lithogeochemistry and Nd isotopic data indicate the rocks are similar to ocean island basalt and alkaline lamprophyres and were generated via low degrees of partial melting of a Neoproterozoic, weakly garnetiferous lithospheric mantle source. The intrusions occur along the intersections of broadly northeast-trending, inherited, Appalachian-cycle lithospheric scale faults with a prominent east-west step in the northeast Newfoundland MOHO along the northeast Newfoundland coast. The convergence of inherited structures with the topographic variation of the lithosphere-asthenosphere boundary likely focused decompression melting of the lithospheric mantle driven through distal, edge-driven upwelling associated with continued extension in the northwest Atlantic. |
format |
Article in Journal/Newspaper |
author |
Sandeman, Hamish A. Peace, Alexander L. |
spellingShingle |
Sandeman, Hamish A. Peace, Alexander L. Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
author_facet |
Sandeman, Hamish A. Peace, Alexander L. |
author_sort |
Sandeman, Hamish A. |
title |
Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
title_short |
Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
title_full |
Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
title_fullStr |
Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
title_full_unstemmed |
Petrochemistry, mineralogy and Nd isotopic analyses of Tithonian alkaline lamprophyric intrusions, north-central Newfoundland, Canada |
title_sort |
petrochemistry, mineralogy and nd isotopic analyses of tithonian alkaline lamprophyric intrusions, north-central newfoundland, canada |
publisher |
Canadian Science Publishing |
publishDate |
2024 |
url |
http://dx.doi.org/10.1139/cjes-2024-0087 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0087 |
long_lat |
ENVELOPE(-54.998,-54.998,49.750,49.750) |
geographic |
Canada Notre Dame Bay |
geographic_facet |
Canada Notre Dame Bay |
genre |
Newfoundland Northwest Atlantic Ocean Island |
genre_facet |
Newfoundland Northwest Atlantic Ocean Island |
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-2024-0087 |
container_title |
Canadian Journal of Earth Sciences |
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1811641364788543488 |