| Titre | Shale and pyrite Re-Os ages from the Hornby Bay and Amundsen basins provide new chronological markers for Mesoproterozoic stratigraphic successions of northern Canada |
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| Auteur | Rainbird, R H ;
Rooney, A D; Creaser, R A; Skulski, T |
| Source | Earth and Planetary Science Letters vol. 548, 116492, 2020 p. 1-10, https://doi.org/10.1016/j.epsl.2020.116492 |
| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200341 |
| Éditeur | Elsevier B.V. |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.epsl.2020.116492 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Nunavut |
| SNRC | 86J; 86K; 86L; 86M; 86N; 86O |
| Lat/Long OENS | -119.6500 -114.7247 68.1386 66.1247 |
| Sujets | osmium; Bassin d'Amundsen ; Bassin d'Hornby Bay ; Bassin d'Elu ; Groupe de Dismal Lakes ; Supergroupe de Shaler ; Sciences et technologie; stratigraphie; Protérozoïque |
| Illustrations | cartes de localisation; échelles stratigraphiques; tableaux |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Corridor de Mackenzie |
| Diffusé | 2020 08 05 |
| Résumé | (disponible en anglais seulement)
Here we present Re-Os geochronological data from two carbonaceous shale units from the Hornby Bay and Amundsen basins that provide important chronological
markers for Mesoproterozoic stratigraphic successions within northern Canada. Shale from the basal Escape Rapids Formation yields a robust depositional age of 1067.3 ± 13.5 Ma for the lowermost Shaler Supergroup of Amundsen basin with a remarkably
unradiogenic initial 187Os/188Os value (0.15), implying that it derived from weathering of juvenile source material, such as basalt. Sedimentological features, indicative of large basin conditions, suggest deposition within an extensive epeiric sea
that was intermittently mixed with waters from an exterior ocean. This age, and the 720 Ma age of the uppermost Shaler Supergroup, constrain deposition of the ~4 km-thick succession to a period of approximately 350 myr, recording sedimentation
through a complete supercontinent cycle - amalgamation through to break-up of Rodinia. Further, it indicates that the Amundsen basin formed at the same time as the Borden, and Fury and Hecla basins on northern Baffin Island, and the Thule basin in
northwestern Greenland, and that these basins were perhaps connected as part of a much larger basin situated in the interior of Rodinia. Diagenetic pyrite from sandstone dykelets in carbonaceous shales of the Fort Confidence Formation yielded a Re-Os
model age of 1438 ± 8 Ma, providing a minimum age for deposition of the lower Dismal Lakes Group of the Hornby Bay basin. This age strengthens proposed regional correlation of the Hornby Bay basin with the large intracontinental Athabasca and Thelon
basins, located on the Rae craton to the southeast, and is evidence for a Laurentia-wide marine flooding episode ca. 1500 Ma. Both new ages place important constraints on newly discovered eukaryotic microfossils from the Shaler Supergroup and Dismal
Lakes Group and calibration points for critical chemostratigraphic data. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Présente deux nouveaux âges pour les roches sédimentaires précambriennes (schistes noirs) de la région de Coppermine, dans le nord du Canada.
Les âges ont été déterminés dans deux laboratoires différents spécialisés en géochronologie Re-Os. Les âges fournissent de nouveaux points d'étalonnage importants pour les coupes stratigraphiques qui n'étaient pas datées auparavant. Les résultats
nous permettent de faire des suggestions sur la corrélation de ces strates avec d'autres roches de cet âge au Canada et dans le monde. Ils nous fournissent également un âge plus précis pour les microfossiles nouvellement découverts, y compris les
plus anciens champignons fossiles de la Terre. |
| GEOSCAN ID | 327029 |
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