New insights into Arctic tectonics: u-pb, (u-th)/he, and hf isotopic data from the Franklinian Basin, Canadian Arctic islands

• Main Author: Anfinson, Owen Anthony
• Other Authors: Leier, Andrew
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Calgary 2012
• Subjects: Arctic; Greenland; East Greenland
• Online Access: http://hdl.handle.net/1880/105716; https://doi.org/10.11575/PRISM/4715

Bibliography: p. 37-46, 75-83, 97-101, 105-106, 110-113 Includes copies of copyright permission. Original copies with original Partial Copyright Licence. 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 ...