New insights into Arctic tectonics: u-pb, (u-th)/he, and hf isotopic data from the Franklinian Basin, Canadian Arctic islands
Date
2012
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Abstract
More than 2300 detrital zircon uranium-lead (U-Pb) ages, 32 6Hf/177Hf (£Hf) isotopic values, 37 apatite helium (AHe) ages, and 72 zircon helium (ZHe) ages represent the first in-depth geochronologic and thermochronologic study of Franklinian Basin strata in the Canadian Arctic and provide new insight on >500 M.y. of geologic history along the northern Laurentian margin (modern orientation). Detrital zircon U-Pb age data demonstrate that the Franklinian Basin succession is composed of strata with three distinctly different provenance signatures. Neoproterozoic and Lower Cambrian formations contain detrital zircon populations consistent with derivation from Archean to Paleoproterozoic gneisses and granites of the west Greenland-northeast Canadian Shield. Lower Silurian to Middle Devonian strata are primarily derived from foreland basin strata of the East Greenland Caledonides (Caledonian orogen). Middle Devonian to Upper Devonian strata also contain detrital zircon populations interpreted as being primarily northerly derived from the continental landmass responsible for the Ellesmerian Orogen ( often referred to as Crockerland). U-Pb age data from basal turbidites of the Middle to Upper Devonian elastic succession suggest Crockerland contributed sediment to the northern Laurentian margin by early-Middle Devonian time and that prior to the Ellesmerian Orogeny Crockerland had a comparable geologic history to the northern Baltica Craton. Detrital zircon U-Pb ages in Upper Devonian strata suggest Crockerland became the dominant source by the end of Franklinian Basin sedimentation.
Mean £Hf values from Paleozoic detrital zircon derived from Crockerland suggest the zircons were primarily formed in either an island arc or continental arc built
on accreted oceanic crust setting. ZHe cooling ages from Middle and Upper Devonian strata were not buried deeper than 7 km since deposition and suggest Crockerland was partially exhumed during the Caledonian Orogen. AHe cooling ages are partially reset since deposition and experienced varying burial histories depending on stratigraphic and geographic location within the basin. AHe ages from Middle Devonian strata from the western margin of the basin indicate episodes of exhumation associated with elastic influxes of sediment into the Sverdrup Basin during the Late Jurassic-Early Cretaceous and Late Cretaceous.
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Bibliography: p. 37-46, 75-83, 97-101, 105-106, 110-113
Includes copies of copyright permission. Original copies with original Partial Copyright Licence.
Includes copies of copyright permission. Original copies with original Partial Copyright Licence.
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Citation
Anfinson, O. A. (2012). New insights into Arctic tectonics: u-pb, (u-th)/he, and hf isotopic data from the Franklinian Basin, Canadian Arctic islands (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4715