| Titre | Provenance, stratigraphic and precise depositional age constraints for an outlier of the 1.9 to 1.8 Ga Nonacho Group, Rae craton, Northwest Territories, Canada |
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| Auteur | Neil, B J C; Gibson, H D; Pehrsson, S J; Martel, E; Thiessen, E J; Crowley, J L |
| Source | Precambrian Research vol. 352, 105999, 2020 p. 1-15, https://doi.org/10.1016/j.precamres.2020.105999  Accès ouvert |
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| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200595 |
| Éditeur | Elsevier B.V. |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.precamres.2020.105999 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Territoires du Nord-Ouest |
| SNRC | 75B; 75C; 75D; 75E; 75F; 75G |
| Lat/Long OENS | -112.6667 -106.3333 63.3333 60.3333 |
| Sujets | zircon; datations au zircon; minéraux détritiques; Groupe de Nonacho ; Craton de Rae ; Orogène de Taltson-Thelon; Sciences et technologie; stratigraphie; géochronologie; Protérozoïque |
| Illustrations | cartes de localisation; diagrammes; graphiques; tableaux |
| Diffusé | 2020 11 06 |
| Résumé | (disponible en anglais seulement)
The Nonacho Group comprises six formations of continental clastic rocks that were deposited between 1.91 and 1.83 Ga. The Nonacho Group is part of a broader
assemblage of conglomerate and sandstone that was deposited atop the Rae craton in response to the amalgamation of Laurentia and supercontinent Nuna, but the details of its tectonic setting are contentious. This paper documents an outlier of Nonacho
Group rocks ~50 km east of the main Nonacho basin. Field observations and LA-ICPMS (laser ablation inductively coupled plasma mass spectrometry) U-Pb detrital zircon geochronology are integrated with previous studies of the main basin to better
understand the group's depositional history, provenance and tectonic setting. The lithology and detrital zircon age spectra of the outlier allow for its correlation to the upper two formations of the Nonacho Group. CA-ID-TIMS (chemical abrasion
isotope dilution thermal ionization mass spectrometry) analyses of two fragments of the youngest detrital zircon provide a maximum depositional age of 1901.0 ± 0.9 Ma. A felsic volcanic cobble dated at ca. 2.38 Ga provides evidence of volcanism
during the Arrowsmith orogeny. Detrital zircon dates recovered from the outlier (ca. 3.4-3.0, 2.7, 2.5-2.3 and 2.0-1.9 Ga) are consistent with derivation from topography of the Taltson and/or Thelon orogens on the western margin of the Rae craton.
Taltson-Thelon (2.0 to 1.9 Ga) aged detritus is only abundant in the upper two formations of the Nonacho Group, marking a change in provenance from the lower formations. This change in provenance may have coincided with a period of renewed uplift and
the unroofing of Taltson-Thelon plutons. The detrital zircon provenance and depositional age of the Nonacho Group is consistent with models that link its deposition to the Taltson and/or Thelon orogens. However, tectonism associated with the 1.9 to
1.8 Ga Snowbird and Trans-Hudson orogens to the east could also have affected basin formation or the change in provenance from the lower to upper Nonacho Group. This study highlights the importance of CA-ID-TIMS in establishing accurate and precise
maximum depositional ages for sedimentary successions. |
| GEOSCAN ID | 327859 |
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