U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska
The Bokan Mountain arfvedsonite–aegirine granite is the only peralkaline acid intrusion actually known on the margin of the Canadian Cordillera. It is the end product of a peralkaline magmatic evolution and is characterized by genetically associated concentrations of U and Th. The U–Pb method on zir...
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Canadian Science Publishing
1983
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crcansciencepubl:10.1139/e83-021 2024-04-07T07:55:34+00:00 U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska Saint-Andre, Bruno de Lancelot, Joël R. Collot, Bernard 1983 http://dx.doi.org/10.1139/e83-021 http://www.nrcresearchpress.com/doi/pdf/10.1139/e83-021 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 20, issue 2, page 236-245 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1983 crcansciencepubl https://doi.org/10.1139/e83-021 2024-03-08T00:37:30Z The Bokan Mountain arfvedsonite–aegirine granite is the only peralkaline acid intrusion actually known on the margin of the Canadian Cordillera. It is the end product of a peralkaline magmatic evolution and is characterized by genetically associated concentrations of U and Th. The U–Pb method on zircons has been used to date two samples: one from a barren peralkaline granite and one from a low-grade U–Th mineralized albitite. A typological study has revealed two genetically different populations of zircons in the barren granite. The upper intercept age of 171 ± 5 Ma obtained on a concordia diagram dates the emplacement of the peralkaline granite. Acid wash experiments on zircons have allowed us to remove important quantities of common lead; this point is discussed as well as the abnormally low Pb content of the feldspar extracted from the barren granite.A Jurassic period of magmatic activity must be integrated into the geological history of Prince of Wales Island. Peralkaline magmatism may have occurred when the Alexander Terrane rifted away from its more southerly area of origin. Article in Journal/Newspaper Prince of Wales Island Alaska Canadian Science Publishing Prince of Wales Island ENVELOPE(-99.001,-99.001,72.668,72.668) Canadian Journal of Earth Sciences 20 2 236 245 |
institution |
Open Polar |
collection |
Canadian Science Publishing |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Saint-Andre, Bruno de Lancelot, Joël R. Collot, Bernard U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
topic_facet |
General Earth and Planetary Sciences |
description |
The Bokan Mountain arfvedsonite–aegirine granite is the only peralkaline acid intrusion actually known on the margin of the Canadian Cordillera. It is the end product of a peralkaline magmatic evolution and is characterized by genetically associated concentrations of U and Th. The U–Pb method on zircons has been used to date two samples: one from a barren peralkaline granite and one from a low-grade U–Th mineralized albitite. A typological study has revealed two genetically different populations of zircons in the barren granite. The upper intercept age of 171 ± 5 Ma obtained on a concordia diagram dates the emplacement of the peralkaline granite. Acid wash experiments on zircons have allowed us to remove important quantities of common lead; this point is discussed as well as the abnormally low Pb content of the feldspar extracted from the barren granite.A Jurassic period of magmatic activity must be integrated into the geological history of Prince of Wales Island. Peralkaline magmatism may have occurred when the Alexander Terrane rifted away from its more southerly area of origin. |
format |
Article in Journal/Newspaper |
author |
Saint-Andre, Bruno de Lancelot, Joël R. Collot, Bernard |
author_facet |
Saint-Andre, Bruno de Lancelot, Joël R. Collot, Bernard |
author_sort |
Saint-Andre, Bruno de |
title |
U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
title_short |
U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
title_full |
U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
title_fullStr |
U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
title_full_unstemmed |
U–Pb geochronology of the Bokan Mountain peralkaline granite, southeastern Alaska |
title_sort |
u–pb geochronology of the bokan mountain peralkaline granite, southeastern alaska |
publisher |
Canadian Science Publishing |
publishDate |
1983 |
url |
http://dx.doi.org/10.1139/e83-021 http://www.nrcresearchpress.com/doi/pdf/10.1139/e83-021 |
long_lat |
ENVELOPE(-99.001,-99.001,72.668,72.668) |
geographic |
Prince of Wales Island |
geographic_facet |
Prince of Wales Island |
genre |
Prince of Wales Island Alaska |
genre_facet |
Prince of Wales Island Alaska |
op_source |
Canadian Journal of Earth Sciences volume 20, issue 2, page 236-245 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e83-021 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
20 |
container_issue |
2 |
container_start_page |
236 |
op_container_end_page |
245 |
_version_ |
1795672802794143744 |