Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology
Miles Canyon basalt is an informal term used to describe numerous exposures of young alkaline olivine basalt flows in southern Yukon. The volcanic rocks are part of the Northern Cordilleran volcanic province. K-Ar and Ar-Ar whole-rock dates indicate that the Miles Canyon succession of flows at the W...
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crcansciencepubl:10.1139/e99-049 2023-12-17T10:51:26+01:00 Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology Hart, Craig JR Villeneuve, Mike 1999 http://dx.doi.org/10.1139/e99-049 http://www.nrcresearchpress.com/doi/pdf/10.1139/e99-049 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 36, issue 9, page 1495-1507 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1999 crcansciencepubl https://doi.org/10.1139/e99-049 2023-11-19T13:39:03Z Miles Canyon basalt is an informal term used to describe numerous exposures of young alkaline olivine basalt flows in southern Yukon. The volcanic rocks are part of the Northern Cordilleran volcanic province. K-Ar and Ar-Ar whole-rock dates indicate that the Miles Canyon succession of flows at the Whitehorse Rapids are clearly Late Miocene in age (ca. 8.4 Ma). The largest exposure of the Miles Canyon basalt occurs at the Alligator Lake volcanic complex where two nearly concordant Pliocene Ar-Ar dates indicate eruption at ca. 3.2 Ma. K-Ar analyses from other sites yield dates of 2.4 and 7.1 Ma and indicate an episodic Neogene volcanic history for the region. There is no evidence of Quaternary or postglacial volcanism. The dates are older than assumed by previous workers, and in some cases the K-Ar dates are strongly discordant from Ar-Ar determinations. More accurate Ar-Ar determinations may result from the method's ability to select smaller amounts of better material for analysis. Excess 40 Ar was not encountered. As a result, the accuracy of any single or several discordant K-Ar determinations for Neogene subaerial volcanic rocks, particularly low-K rocks such as basalts, should be questioned and resulting interpretations made with caution. Models accounting for the eruption of the Northern Cordilleran volcanic province lavas have typically relied upon extension along north-trending faults that were generated by stresses along the continental margin. However, we consider a slab window model which better accounts for the initiation and distribution of northern Cordilleran Neogene volcanic activity. Article in Journal/Newspaper Whitehorse Yukon Canadian Science Publishing (via Crossref) Yukon Canada Whitehorse Rapids ENVELOPE(-135.044,-135.044,60.694,60.694) Miles Canyon ENVELOPE(-135.034,-135.034,60.666,60.666) Alligator Lake ENVELOPE(-135.354,-135.354,60.385,60.385) Canadian Journal of Earth Sciences 36 9 1495 1507 |
institution |
Open Polar |
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Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Hart, Craig JR Villeneuve, Mike Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
topic_facet |
General Earth and Planetary Sciences |
description |
Miles Canyon basalt is an informal term used to describe numerous exposures of young alkaline olivine basalt flows in southern Yukon. The volcanic rocks are part of the Northern Cordilleran volcanic province. K-Ar and Ar-Ar whole-rock dates indicate that the Miles Canyon succession of flows at the Whitehorse Rapids are clearly Late Miocene in age (ca. 8.4 Ma). The largest exposure of the Miles Canyon basalt occurs at the Alligator Lake volcanic complex where two nearly concordant Pliocene Ar-Ar dates indicate eruption at ca. 3.2 Ma. K-Ar analyses from other sites yield dates of 2.4 and 7.1 Ma and indicate an episodic Neogene volcanic history for the region. There is no evidence of Quaternary or postglacial volcanism. The dates are older than assumed by previous workers, and in some cases the K-Ar dates are strongly discordant from Ar-Ar determinations. More accurate Ar-Ar determinations may result from the method's ability to select smaller amounts of better material for analysis. Excess 40 Ar was not encountered. As a result, the accuracy of any single or several discordant K-Ar determinations for Neogene subaerial volcanic rocks, particularly low-K rocks such as basalts, should be questioned and resulting interpretations made with caution. Models accounting for the eruption of the Northern Cordilleran volcanic province lavas have typically relied upon extension along north-trending faults that were generated by stresses along the continental margin. However, we consider a slab window model which better accounts for the initiation and distribution of northern Cordilleran Neogene volcanic activity. |
format |
Article in Journal/Newspaper |
author |
Hart, Craig JR Villeneuve, Mike |
author_facet |
Hart, Craig JR Villeneuve, Mike |
author_sort |
Hart, Craig JR |
title |
Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
title_short |
Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
title_full |
Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
title_fullStr |
Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
title_full_unstemmed |
Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40 Ar/ 39 Ar and K-Ar geochronology |
title_sort |
geochronology of neogene alkaline volcanic rocks (miles canyon basalt), southern yukon territory, canada: the relative effectiveness of laser 40 ar/ 39 ar and k-ar geochronology |
publisher |
Canadian Science Publishing |
publishDate |
1999 |
url |
http://dx.doi.org/10.1139/e99-049 http://www.nrcresearchpress.com/doi/pdf/10.1139/e99-049 |
long_lat |
ENVELOPE(-135.044,-135.044,60.694,60.694) ENVELOPE(-135.034,-135.034,60.666,60.666) ENVELOPE(-135.354,-135.354,60.385,60.385) |
geographic |
Yukon Canada Whitehorse Rapids Miles Canyon Alligator Lake |
geographic_facet |
Yukon Canada Whitehorse Rapids Miles Canyon Alligator Lake |
genre |
Whitehorse Yukon |
genre_facet |
Whitehorse Yukon |
op_source |
Canadian Journal of Earth Sciences volume 36, issue 9, page 1495-1507 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e99-049 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
36 |
container_issue |
9 |
container_start_page |
1495 |
op_container_end_page |
1507 |
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1785576694278520832 |