| Titre | The age and provenance of the Lay Range assemblage provides an indirect record of basement to north-central Quesnellia, British Columbia |
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| Auteur | Ootes, L; Ferri, F; Milidragovic, D ; Wall, C |
| Source | Geological fieldwork 2021: a summary of field activities and current research; British Columbia Geological Survey Geological Fieldwork Paper 2022-01, 2022 p. 31-44  Accès ouvert |
| Liens | Online - En ligne (PDF, 3.88 MB)
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| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210442 |
| Éditeur | British Columbia Geological Survey |
| Document | publication en série |
| Lang. | anglais |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Colombie-Britannique |
| SNRC | 94C/12 |
| Lat/Long OENS | -126.0000 -125.8667 56.6333 56.5167 |
| Sujets | datations au uranium-plomb; rapports uranium-plomb; hafnium; analyses des éléments en trace; répartition des éléments en trace; géochimie des éléments en trace; datations au zircon; antecedents de
sedimentation; cycles sédimentaires; origine; minéraux détritiques; antécédents tectoniques; magmatisme; soulèvement de la croûte; lithostratigraphie; biostratigraphie; Archéen; Terrane de Quesnel ; Assemblage de Lay Range ; Terrane de Quesnellia ;
stratigraphie; géochronologie; paléontologie; Sciences et technologie; Nature et environnement; Phanérozoïque; Paléozoïque; Permien; Carbonifère; Dévonien; Ordovicien; Cambrien; Précambrien; Protérozoïque |
| Illustrations | cartes de localisation; échelles stratigraphiques; tableaux; photographies; cartes géologiques généralisées; graphiques; diagrammes de distribution des éléments |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux L'ouest de la Cordillère |
| Diffusé | 2022 01 31 |
| Résumé | (disponible en anglais seulement)
The Lay Range assemblage, the lowest exposed lithostratigraphic unit of north-central Quesnellia, is separated into lower sedimentary and upper mafi c tuff
divisions. Fossil and field evidence indicates deposition of the lower sedimentary division during the Late Mississippian to Middle Pennsylvanian and of the upper mafic tuff division during the Middle Pennsylvanian to early Permian. A quartz
sandstone and polymictic pebble conglomerate from the lower part of the lower sedimentary division yield detrital zircon U-Pb ages between 360 and 290 Ma (Carboniferous to early Permian), with a range of older detrital zircons from ca. 3600 to 890 Ma
(Archean and Proterozoic). A small population of zircons ranges from 450 to 390 Ma (n=4; Ordovician to Devonian). The Carboniferous detrital zircons have mostly juvenile EHf(t), indicating that the parental magmas did not interact with older crust.
Few zircons are more evolved and were derived from parental magmas that interacted with or melted from crust as old as middle Mesoproterozoic. The combined EHf(t) and trace element compositions of detrital zircon are consistent with formation in a
juvenile arc during the Carboniferous. Comparison of Lay Range detrital zircon U-Pb, Hf, and trace element systematics indicate a similar timing of arc magmatism with eastern Stikinia and Wrangellia, but little relationship to ancient North America
or Yukon-Tanana terrane. The older detrital zircons (Archean through Paleozoic) were sourced from a fringing landmass, possibly a continental oceanic plateau, that had little to no role in the petrogenesis of the Carboniferous magmas. The spread of
ages in the Lay Range assemblage zircon distributions likely records multiple cycles of deposition, uplift, erosion, transport, and sedimentation. One possibility is that the fringing landmass was calved from the Neoproterozoic through Cambrian
western North American passive margin. |
| Sommaire | (Résumé en langage clair et simple, non publié)
L'âge et l'affinité du socle avec l'arc insulaire exotique terrane Quesnellia sont mal connus, mais on suppose qu'ils dérivent d'une croûte
nord-américaine atténuée. Les nouvelles données isotopiques (U/Pb et Hf) et d'éléments traces du zircon et de la division sédimentaire inférieure de l'assemblage de Lay Range (carbonifère) limitent l'âge des strates les plus exposées du centre du
Quesnellia, et indiquent la formation dans un arc volcanique juvénile avec contribution limitée d'une masse continentale qui contenait du zircon d'âge archéen à paléozoïque. |
| GEOSCAN ID | 329292 |
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