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Baltican crustal provenance for Cambrian-Ordovician sandstones of the Alexander Terrane, North American Cordillera; evidence from detrital zircon U-Pb geochronology and Hf isotope geochemistry

Luke P. Beranek, Cees R. van Staal, William C. McClelland, Steve Israel and Mitch G. Mihalynuk
Baltican crustal provenance for Cambrian-Ordovician sandstones of the Alexander Terrane, North American Cordillera; evidence from detrital zircon U-Pb geochronology and Hf isotope geochemistry
Journal of the Geological Society of London (January 2013) 170 (1): 7-18

Abstract

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.


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: 170
Serial Issue: 1
Title: Baltican crustal provenance for Cambrian-Ordovician sandstones of the Alexander Terrane, North American Cordillera; evidence from detrital zircon U-Pb geochronology and Hf isotope geochemistry
Affiliation: Geological Survey of Canada, Vancouver, BC, United States
Pages: 7-18
Published: 201301
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 89
Accession Number: 2013-018225
Categories: Structural geologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Supplemental information/data is available in the online version of this article
Illustration Description: illus. incl. strat. cols., geol. sketch maps
N42°00'00" - N84°00'00", W141°00'00" - W52°00'00"
N52°30'00" - N75°00'00", E82°00'00" - E139°00'00"
Secondary Affiliation: University of Iowa, USA, United StatesYukon Geological Survey, CAN, CanadaBritish Columbia Geological Survey, CAN, Canada
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201312
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