Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories
Geochronological and Pb isotopic studies were carried out to constrain the petrogenesis, emplacement age(s), and relationships of the Little Nahanni pegmatite group to other granitoids in the region. A U–Pb age of 81.6 ± 0.5 Ma for columbite was obtained. K–Ar ages for micas were determined to be 65...
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1995
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crcansciencepubl:10.1139/e95-162 2024-09-15T18:26:37+00:00 Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories Mauthner, M. H. F. Mortensen, J. K. Groat, L. A. Ercit, T. S. 1995 http://dx.doi.org/10.1139/e95-162 http://www.nrcresearchpress.com/doi/pdf/10.1139/e95-162 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 32, issue 12, page 2090-2097 ISSN 0008-4077 1480-3313 journal-article 1995 crcansciencepubl https://doi.org/10.1139/e95-162 2024-08-29T04:08:47Z Geochronological and Pb isotopic studies were carried out to constrain the petrogenesis, emplacement age(s), and relationships of the Little Nahanni pegmatite group to other granitoids in the region. A U–Pb age of 81.6 ± 0.5 Ma for columbite was obtained. K–Ar ages for micas were determined to be 65.4 ± 4.0 Ma for muscovite and 65.8 ± 3.4 and 65 ± 3 Ma for lepidolite. The U–Pb age is interpreted as the emplacement age for the pegmatites, and the K–Ar ages are interpreted to be the timing of a thermal event responsible for resetting the K–Ar mica system. The U–Pb columbite age is 8–13 Ma younger than the average age of the plutons in the Selwyn plutonic suite and indicates that these pegmatites represent a magmatic event that has not been previously recognized. Likewise, the K–Ar ages point to a later thermal event not previously recognized in this area. The results of our studies demonstrate the utility of the U–Pb columbite geochronometer in dating relatively young pegmatite systems. Article in Journal/Newspaper Northwest Territories Canadian Science Publishing Canadian Journal of Earth Sciences 32 12 2090 2097 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
Geochronological and Pb isotopic studies were carried out to constrain the petrogenesis, emplacement age(s), and relationships of the Little Nahanni pegmatite group to other granitoids in the region. A U–Pb age of 81.6 ± 0.5 Ma for columbite was obtained. K–Ar ages for micas were determined to be 65.4 ± 4.0 Ma for muscovite and 65.8 ± 3.4 and 65 ± 3 Ma for lepidolite. The U–Pb age is interpreted as the emplacement age for the pegmatites, and the K–Ar ages are interpreted to be the timing of a thermal event responsible for resetting the K–Ar mica system. The U–Pb columbite age is 8–13 Ma younger than the average age of the plutons in the Selwyn plutonic suite and indicates that these pegmatites represent a magmatic event that has not been previously recognized. Likewise, the K–Ar ages point to a later thermal event not previously recognized in this area. The results of our studies demonstrate the utility of the U–Pb columbite geochronometer in dating relatively young pegmatite systems. |
format |
Article in Journal/Newspaper |
author |
Mauthner, M. H. F. Mortensen, J. K. Groat, L. A. Ercit, T. S. |
spellingShingle |
Mauthner, M. H. F. Mortensen, J. K. Groat, L. A. Ercit, T. S. Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
author_facet |
Mauthner, M. H. F. Mortensen, J. K. Groat, L. A. Ercit, T. S. |
author_sort |
Mauthner, M. H. F. |
title |
Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
title_short |
Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
title_full |
Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
title_fullStr |
Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
title_full_unstemmed |
Geochronology of the Little Nahanni pegmatite group, Selwyn Mountains, southwestern Northwest Territories |
title_sort |
geochronology of the little nahanni pegmatite group, selwyn mountains, southwestern northwest territories |
publisher |
Canadian Science Publishing |
publishDate |
1995 |
url |
http://dx.doi.org/10.1139/e95-162 http://www.nrcresearchpress.com/doi/pdf/10.1139/e95-162 |
genre |
Northwest Territories |
genre_facet |
Northwest Territories |
op_source |
Canadian Journal of Earth Sciences volume 32, issue 12, page 2090-2097 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e95-162 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
32 |
container_issue |
12 |
container_start_page |
2090 |
op_container_end_page |
2097 |
_version_ |
1810467137213431808 |