Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada
An Archaean carbonatite-bearing alkaline complex, the Grays Bay alkaline complex, has been mapped in the Slave Province of northwestern Canada. It consists of five sequentially emplaced phases: a melanocratic syenite, a carbonatite and silico-carbonatite, a pegmatitic biotite syenite and fine-graine...
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fthighwire:oai:open-archive.highwire.org:petrology:39/11-12/1975 2023-05-15T16:22:52+02:00 Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada Villeneuve, M. E. Relf, C. 1998-11-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/39/11-12/1975 https://doi.org/10.1093/petroj/39.11-12.1975 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/39/11-12/1975 http://dx.doi.org/10.1093/petroj/39.11-12.1975 Copyright (C) 1998, Oxford University Press Articles TEXT 1998 fthighwire https://doi.org/10.1093/petroj/39.11-12.1975 2018-04-07T06:23:21Z An Archaean carbonatite-bearing alkaline complex, the Grays Bay alkaline complex, has been mapped in the Slave Province of northwestern Canada. It consists of five sequentially emplaced phases: a melanocratic syenite, a carbonatite and silico-carbonatite, a pegmatitic biotite syenite and fine-grained biotite–clinopyroxene–plagioclase gabbro dykes The entire complex is tightly folded in concert with late Archaean regional upright folding. A minimum age of 2605.8+2.8/–2.5 Ma for the melanocratic syenite is determined by U/Pb dating of titanite, an alteration product o primary ilmenite. A single concordant zircon from the same unit, interpreted as xenocrystic, places an upper age limit of ∼2.67 Ga. Monazite from the carbonatite yields an age of 2594.8 ±2.0 Ma, indicating that a minimum of 6.5 my passed between the intrusion of syenite and carbonatite magmas. A second carbonatite-bearing complex in the southwestern Slave Province, the Leith Lake carbonatite, was dated by U/Pb titanite at 2591.8+3.3/–2.8 Ga, within error of the Grays Bay alkaline complex. The synchroneity between the two widely separated complexes suggests that intrusion of these bodies may have been a pan-Slave Province event. The carbonatite complexes are temporally coincident with two major tectonic events in the Slave Province: (1) emplacement of voluminous, crustally derived monzogranite to granodiorite plutons between ∼2.61 and 2.59 Ga; (2) deposition of polymictic conglomerate after ∼2.60 Ga within localized fault-bounded basins. Both events are represented in the Grays Bay area. The duration of uplift and conglomerate deposition is poorly defined, but coincident deformation of conglomerates, the alkaline complexes and granitic plutons suggests a terminal compressive event after 2.59 Ga. Text Grays Bay HighWire Press (Stanford University) Canada Leith ENVELOPE(-62.800,-62.800,-64.867,-64.867) Grays Bay ENVELOPE(-111.053,-111.053,67.818,67.818) Leith Lake ENVELOPE(-119.218,-119.218,65.692,65.692) Journal of Petrology 39 11-12 1975 1986 |
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HighWire Press (Stanford University) |
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English |
topic |
Articles |
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Articles Villeneuve, M. E. Relf, C. Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
topic_facet |
Articles |
description |
An Archaean carbonatite-bearing alkaline complex, the Grays Bay alkaline complex, has been mapped in the Slave Province of northwestern Canada. It consists of five sequentially emplaced phases: a melanocratic syenite, a carbonatite and silico-carbonatite, a pegmatitic biotite syenite and fine-grained biotite–clinopyroxene–plagioclase gabbro dykes The entire complex is tightly folded in concert with late Archaean regional upright folding. A minimum age of 2605.8+2.8/–2.5 Ma for the melanocratic syenite is determined by U/Pb dating of titanite, an alteration product o primary ilmenite. A single concordant zircon from the same unit, interpreted as xenocrystic, places an upper age limit of ∼2.67 Ga. Monazite from the carbonatite yields an age of 2594.8 ±2.0 Ma, indicating that a minimum of 6.5 my passed between the intrusion of syenite and carbonatite magmas. A second carbonatite-bearing complex in the southwestern Slave Province, the Leith Lake carbonatite, was dated by U/Pb titanite at 2591.8+3.3/–2.8 Ga, within error of the Grays Bay alkaline complex. The synchroneity between the two widely separated complexes suggests that intrusion of these bodies may have been a pan-Slave Province event. The carbonatite complexes are temporally coincident with two major tectonic events in the Slave Province: (1) emplacement of voluminous, crustally derived monzogranite to granodiorite plutons between ∼2.61 and 2.59 Ga; (2) deposition of polymictic conglomerate after ∼2.60 Ga within localized fault-bounded basins. Both events are represented in the Grays Bay area. The duration of uplift and conglomerate deposition is poorly defined, but coincident deformation of conglomerates, the alkaline complexes and granitic plutons suggests a terminal compressive event after 2.59 Ga. |
format |
Text |
author |
Villeneuve, M. E. Relf, C. |
author_facet |
Villeneuve, M. E. Relf, C. |
author_sort |
Villeneuve, M. E. |
title |
Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
title_short |
Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
title_full |
Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
title_fullStr |
Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
title_full_unstemmed |
Tectonic Setting of 2.6 Ga Carbonatites in the Slave Province, NW Canada |
title_sort |
tectonic setting of 2.6 ga carbonatites in the slave province, nw canada |
publisher |
Oxford University Press |
publishDate |
1998 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/39/11-12/1975 https://doi.org/10.1093/petroj/39.11-12.1975 |
long_lat |
ENVELOPE(-62.800,-62.800,-64.867,-64.867) ENVELOPE(-111.053,-111.053,67.818,67.818) ENVELOPE(-119.218,-119.218,65.692,65.692) |
geographic |
Canada Leith Grays Bay Leith Lake |
geographic_facet |
Canada Leith Grays Bay Leith Lake |
genre |
Grays Bay |
genre_facet |
Grays Bay |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/39/11-12/1975 http://dx.doi.org/10.1093/petroj/39.11-12.1975 |
op_rights |
Copyright (C) 1998, Oxford University Press |
op_doi |
https://doi.org/10.1093/petroj/39.11-12.1975 |
container_title |
Journal of Petrology |
container_volume |
39 |
container_issue |
11-12 |
container_start_page |
1975 |
op_container_end_page |
1986 |
_version_ |
1766010997603041280 |