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TitreBaltican crustal provenance for Cambrian - Ordovician sandstones of the Alexander terrane, North American Cordillera: evidence from detrital zircon U-Pb geochronology and Hf isotope geochemistry
AuteurBeranek, L P; van Staal, C R; McClelland, W C; Israel, S; Mihalynuk, M G
SourceJournal of the Geological Society vol. 170, 2013 p. 7-18, https://doi.org/10.1144/jgs2012-028
Année2013
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120180
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1144/jgs2012-028
Mediapapier; en ligne; numérique
Formatspdf
ProvinceColombie-Britannique; Yukon
SNRC92; 93C; 93D; 93E; 103; 104; 114; 105C; 105D; 105E; 115A; 115B; 115C
Lat/Long OENS-148.0000 -90.0000 62.0000 32.0000
Sujetsisotopes; rapports isotopiques; rapports uranium-plomb; études de la croûte; evolution de la croûte; mouvements de la croûte; roches sédimentaires; grès; origine; Terrane d'Alexander ; Cordillère; géochronologie; géochimie; Paléozoïque; Ordovicien; Cambrien
Illustrationslocation maps; histograms; stratigraphic columns
ProgrammeGisements polymétalliques - nord-ouest de la Cordillère canadienne (Yukon et Colombie-Britannique), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Detrital zircon U-Pb geochronology and hf isotope geochemistry allow us to decipher the crustal provenance of Cambrian - Ordovician backarc basin strata of the Alexander terrane, North American Cordillera, and evaluate models for its origin and displacement history relative to Baltica, Gondwana, Siberia, and Laurentia. Quartzose shallow-marine sandstones of the Alexander terrane contain a range of Neoproterozoic to Neoarchaean detrital zircons with the most dominant age groupings c. 565 - 760, 1000 - 1250, 1450, and 1650 Ma. Subordinate volcaniclastic sandstones yield Cambrian and Ordovician detrital zircons with a prominent age peak at 477 Ma. The detrital zircon age signatures resemble coeval strata in the Eurasian high Arctic, and in combination with faunal and palaeomagnetic constraints suggest provenance from local magmatic rocks and the Timanide orogenic belt and Fennoscandian Shield of NE Baltica. The hf isotopic compositions of Palaeozoic to Neoarchaean detrital zircons strongly favour Baltican crustal sources instead of similar-aged domains of Gondwana. The Alexander terrane formed part of an arc system that fringed the Uralian passive margin, and its position in the Uralian Seaway allowed faunal exchange between the Siberian and Baltican platforms. The available evidence suggests that the Alexander terrane originated in the Northern hemisphere and migrated to the palaeo-Pacific Ocean by travelling around northern Laurentia.
GEOSCAN ID291777