The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study

Legacy U–Pb isotopic data are reported for the Mesoarchean Central Slave Cover Group and Neoarchean Yellowknife greenstone belt, Slave craton, Northwest Territories, Canada. In two locations north of the City of Yellowknife, exposures of cover group rocks occur beneath mafic volcanic and subvolcanic...

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Published in:Canadian Journal of Earth Sciences
Main Authors: Ketchum, John W.F., Bleeker, Wouter, Falck, Hendrik, Jackson, Valerie A.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 2024
Subjects:
Online Access:http://dx.doi.org/10.1139/cjes-2024-0028
https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2024-0028
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spelling crcansciencepubl:10.1139/cjes-2024-0028 2024-09-30T14:40:27+00:00 The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study Ketchum, John W.F. Bleeker, Wouter Falck, Hendrik Jackson, Valerie A. 2024 http://dx.doi.org/10.1139/cjes-2024-0028 https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2024-0028 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0028 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-2024-0028 2024-09-19T04:09:48Z Legacy U–Pb isotopic data are reported for the Mesoarchean Central Slave Cover Group and Neoarchean Yellowknife greenstone belt, Slave craton, Northwest Territories, Canada. In two locations north of the City of Yellowknife, exposures of cover group rocks occur beneath mafic volcanic and subvolcanic units traditionally assigned to the basal Chan Formation of the Kam Group. Both cover group occurrences contain felsic volcanic tuff units that yield eruption ages of 2853 + 2/−1.5 Ma and 2826 ± 1.5 Ma. The younger tuff is underlain by felsic volcaniclastic schist with a dominant, basement-aged detrital zircon population that was deposited after 2840 ± 6 Ma. Near the south end of the exposed greenstone belt, a felsic tuff within the Octopus Formation provides an age of 2699 ± 3 Ma, confirming that this formation is not part of the Central Slave Cover Group. A pillowed basalt flow within the Chan Formation is cut by a composite gabbro dyke dated as 2738 +3.5/−3 Ma. However, a more general ca. 2730–2740 Ma age interpretation for this dyke may be appropriate due to the potential for complex lead loss behaviour in the dated baddeleyite fractions. Younger U–Pb zircon and monazite ages reported herein (2710–2706 Ma) contribute to our understanding of felsic magmatic and gold-mineralizing events that influenced later development of the Yellowknife greenstone belt. Although the depositional history of the autochthonous Central Slave Cover Group is becoming better known, questions remain regarding the age and tectonomagmatic affinity of adjacent mafic volcanic rocks traditionally assigned to the Kam Group and correlative assemblages. Are some of these rocks actually part of the Central Slave Cover Group? Article in Journal/Newspaper Northwest Territories Yellowknife Canadian Science Publishing Canada Northwest Territories Yellowknife Canadian Journal of Earth Sciences
institution Open Polar
collection Canadian Science Publishing
op_collection_id crcansciencepubl
language English
description Legacy U–Pb isotopic data are reported for the Mesoarchean Central Slave Cover Group and Neoarchean Yellowknife greenstone belt, Slave craton, Northwest Territories, Canada. In two locations north of the City of Yellowknife, exposures of cover group rocks occur beneath mafic volcanic and subvolcanic units traditionally assigned to the basal Chan Formation of the Kam Group. Both cover group occurrences contain felsic volcanic tuff units that yield eruption ages of 2853 + 2/−1.5 Ma and 2826 ± 1.5 Ma. The younger tuff is underlain by felsic volcaniclastic schist with a dominant, basement-aged detrital zircon population that was deposited after 2840 ± 6 Ma. Near the south end of the exposed greenstone belt, a felsic tuff within the Octopus Formation provides an age of 2699 ± 3 Ma, confirming that this formation is not part of the Central Slave Cover Group. A pillowed basalt flow within the Chan Formation is cut by a composite gabbro dyke dated as 2738 +3.5/−3 Ma. However, a more general ca. 2730–2740 Ma age interpretation for this dyke may be appropriate due to the potential for complex lead loss behaviour in the dated baddeleyite fractions. Younger U–Pb zircon and monazite ages reported herein (2710–2706 Ma) contribute to our understanding of felsic magmatic and gold-mineralizing events that influenced later development of the Yellowknife greenstone belt. Although the depositional history of the autochthonous Central Slave Cover Group is becoming better known, questions remain regarding the age and tectonomagmatic affinity of adjacent mafic volcanic rocks traditionally assigned to the Kam Group and correlative assemblages. Are some of these rocks actually part of the Central Slave Cover Group?
format Article in Journal/Newspaper
author Ketchum, John W.F.
Bleeker, Wouter
Falck, Hendrik
Jackson, Valerie A.
spellingShingle Ketchum, John W.F.
Bleeker, Wouter
Falck, Hendrik
Jackson, Valerie A.
The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
author_facet Ketchum, John W.F.
Bleeker, Wouter
Falck, Hendrik
Jackson, Valerie A.
author_sort Ketchum, John W.F.
title The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
title_short The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
title_full The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
title_fullStr The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
title_full_unstemmed The Yellowknife greenstone belt and underlying Central Slave Cover Group, Slave craton, Canada: constraints and questions arising from a U–Pb dating study
title_sort yellowknife greenstone belt and underlying central slave cover group, slave craton, canada: constraints and questions arising from a u–pb dating study
publisher Canadian Science Publishing
publishDate 2024
url http://dx.doi.org/10.1139/cjes-2024-0028
https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2024-0028
https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2024-0028
geographic Canada
Northwest Territories
Yellowknife
geographic_facet Canada
Northwest Territories
Yellowknife
genre Northwest Territories
Yellowknife
genre_facet Northwest Territories
Yellowknife
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-2024-0028
container_title Canadian Journal of Earth Sciences
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