Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia
The Marble Mountain area of west-central Cape Breton Island is underlain mainly by granitoid rocks of the Marble Mountain, Big Brook, and West Bay plutons, migmatitic gneisses of the Lime Hill gneissic complex, and low-grade metasedimentaiy rocks of the Malagawatch Formation. The Late Precambrian Ma...
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Atlantic Geoscience Society
1994
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ftuninewbrunojs:oai:ojs.journals.lib.unb.ca:article/2119 2023-05-15T15:46:45+02:00 Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia Justino, Mario F. Barr, Sandra M. 1994-03-01 application/pdf https://journals.lib.unb.ca/index.php/ag/article/view/2119 eng eng Atlantic Geoscience Society https://journals.lib.unb.ca/index.php/ag/article/view/2119/2483 https://journals.lib.unb.ca/index.php/ag/article/view/2119 Copyright (c) 2015 Atlantic Geology Atlantic Geoscience; Vol. 30 No. 1 (1994) 2564-2987 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion research-article 1994 ftuninewbrunojs 2022-07-11T11:41:57Z The Marble Mountain area of west-central Cape Breton Island is underlain mainly by granitoid rocks of the Marble Mountain, Big Brook, and West Bay plutons, migmatitic gneisses of the Lime Hill gneissic complex, and low-grade metasedimentaiy rocks of the Malagawatch Formation. The Late Precambrian Marble Mountain and Big Brook plutons are composed of homblende-biotite tonalite to granodioritc. These plutons underwent similar but separate evolutionary histories involving fractionation of plagioclase and hornblende ± biotitc. They display penological similarities to Cordilleran I-type suites, as exemplified by the Peninsular Ranges Batholith, and are interpreted to have formed by partial melting of a mainly basaltic source, and to represent the root zone of a primitive volcanic arc at a convergent plate margin. In contrast, the West Bay Pluton consists of megacrystic monzogranite and associated, probably co-genetic, granitic porphyritic dykes. The pluton is a felsic granite with I-type mineralogy but displays evolutionary trends distinct from typical felsic I-, S-, and A-type granites. The tectonic setting is interpreted to be post-orogenic, and the magma may have formed by a high degree of partial melting of a mainly crust al source. The age of the West Bay Pluton is uncertain, but may be Early Ordovician, based on penological similarity to other granitic plutons in the Bras d'Or terrane which have yielded U-Pb (zircon) ages of ca. 495 Ma. RÉSUMÉ La région du mont Marble du centre-ouest de l'ile-du-Cap-Breton comprend principalement des roches granitiques des plutons du mont Marble, du ruisseau Big et de la baie Ouest, des gneiss migmatitiques du complcxc gneissique de la colline Hill et des roches métasédimentaires de faible grade de la Formation de Mallagawatch. Les plutons du mont Marble et du ruisseau Big, du précambrien tardif sont composés de tonalite a hornblende et biotitc et de granodiorite. Ces plutons ont connu des évolutions ... Article in Journal/Newspaper Breton Island University of New Brunswick: Centre for Digital Scholarship Journals Breton Island ENVELOPE(141.383,141.383,-66.800,-66.800) West Bay ENVELOPE(-36.584,-36.584,-54.237,-54.237) Big Brook ENVELOPE(-56.148,-56.148,51.517,51.517) Atlantic Geology 30 1 |
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Open Polar |
collection |
University of New Brunswick: Centre for Digital Scholarship Journals |
op_collection_id |
ftuninewbrunojs |
language |
English |
description |
The Marble Mountain area of west-central Cape Breton Island is underlain mainly by granitoid rocks of the Marble Mountain, Big Brook, and West Bay plutons, migmatitic gneisses of the Lime Hill gneissic complex, and low-grade metasedimentaiy rocks of the Malagawatch Formation. The Late Precambrian Marble Mountain and Big Brook plutons are composed of homblende-biotite tonalite to granodioritc. These plutons underwent similar but separate evolutionary histories involving fractionation of plagioclase and hornblende ± biotitc. They display penological similarities to Cordilleran I-type suites, as exemplified by the Peninsular Ranges Batholith, and are interpreted to have formed by partial melting of a mainly basaltic source, and to represent the root zone of a primitive volcanic arc at a convergent plate margin. In contrast, the West Bay Pluton consists of megacrystic monzogranite and associated, probably co-genetic, granitic porphyritic dykes. The pluton is a felsic granite with I-type mineralogy but displays evolutionary trends distinct from typical felsic I-, S-, and A-type granites. The tectonic setting is interpreted to be post-orogenic, and the magma may have formed by a high degree of partial melting of a mainly crust al source. The age of the West Bay Pluton is uncertain, but may be Early Ordovician, based on penological similarity to other granitic plutons in the Bras d'Or terrane which have yielded U-Pb (zircon) ages of ca. 495 Ma. RÉSUMÉ La région du mont Marble du centre-ouest de l'ile-du-Cap-Breton comprend principalement des roches granitiques des plutons du mont Marble, du ruisseau Big et de la baie Ouest, des gneiss migmatitiques du complcxc gneissique de la colline Hill et des roches métasédimentaires de faible grade de la Formation de Mallagawatch. Les plutons du mont Marble et du ruisseau Big, du précambrien tardif sont composés de tonalite a hornblende et biotitc et de granodiorite. Ces plutons ont connu des évolutions ... |
format |
Article in Journal/Newspaper |
author |
Justino, Mario F. Barr, Sandra M. |
spellingShingle |
Justino, Mario F. Barr, Sandra M. Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
author_facet |
Justino, Mario F. Barr, Sandra M. |
author_sort |
Justino, Mario F. |
title |
Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
title_short |
Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
title_full |
Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
title_fullStr |
Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
title_full_unstemmed |
Petrology, petrogenesis and tectonic setting of plutonic rocks in the North Mountain area, west-central Cape Breton Island, Nova Scotia |
title_sort |
petrology, petrogenesis and tectonic setting of plutonic rocks in the north mountain area, west-central cape breton island, nova scotia |
publisher |
Atlantic Geoscience Society |
publishDate |
1994 |
url |
https://journals.lib.unb.ca/index.php/ag/article/view/2119 |
long_lat |
ENVELOPE(141.383,141.383,-66.800,-66.800) ENVELOPE(-36.584,-36.584,-54.237,-54.237) ENVELOPE(-56.148,-56.148,51.517,51.517) |
geographic |
Breton Island West Bay Big Brook |
geographic_facet |
Breton Island West Bay Big Brook |
genre |
Breton Island |
genre_facet |
Breton Island |
op_source |
Atlantic Geoscience; Vol. 30 No. 1 (1994) 2564-2987 |
op_relation |
https://journals.lib.unb.ca/index.php/ag/article/view/2119/2483 https://journals.lib.unb.ca/index.php/ag/article/view/2119 |
op_rights |
Copyright (c) 2015 Atlantic Geology |
container_title |
Atlantic Geology |
container_volume |
30 |
container_issue |
1 |
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1766381453985185792 |