Journal article
Reinterpretation of a major terrane boundary in the northern Svalbard Caledonides based on metamorphic fingerprinting of rocks in northern Spitsbergen
Canadian journal of earth sciences, Vol.60(8), pp.1188-1205
08/2023
DOI: 10.1139/cjes-2022-0002
Abstract
Tectonic models for development of the Svalbard Caledonides depend on reliable assessment of the metamorphic evolution of the various basement provinces involved. The Mosselhalvoya Group (MG) and the Atomfjella Complex (AC) have previously been assigned to the Nordaustlandet and West Ny-Friesland terranes, respectively. New analytical data and petrographic observations indicate that both units experienced two-stage metamorphism under similar pressure-temperature (P-T) conditions. Two stages of amphibolite facies metamorphism (M1 and M2) are clearly recorded by garnet and staurolite porphyroblast textures. The results of thermodynamic phase equilibrium modeling indicate that peak M2 metamorphism occurred at similar to 7-7.5 kbar and 590-600 degrees C in both units. Zirconium-in-rutile trace element thermometry confirms the temperature estimates for M1 and M2 stages of metamorphism. Monazite chemical Th-U-Pb dates from the MG resolve a two-stage garnet growth at 444 +/- 7 Ma (M1) and 423 +/- 6 Ma (M2). In contrast, monazite dated in the AC defines a single age of 420 +/- 4 Ma interpreted as M2 growth. We suggest M2 was coeval with early strike-slip motion along the Billefjorden Fault Zone, whereas M1 reflects initial tectonic burial of the studied units. The similarity in metamorphic history between the both units suggests that the boundary between them is a subordinate thrust fault within the Atomfjella thrust stack rather than a major boundary separating the Nordaustlandet and West Ny-Friesland terranes. The MG should be included within the West Ny-Friesland terrane and the tectonic boundary with the Nordaustlandet terrane is likely the Eolussletta Shear Zone.
Details
- Title: Subtitle
- Reinterpretation of a major terrane boundary in the northern Svalbard Caledonides based on metamorphic fingerprinting of rocks in northern Spitsbergen
- Creators
- Jakub Bazarnik - Polish Geological InstituteKarolina Kosminska - AGH University of KrakowWilliam C. McClelland - University of IowaJustin Strauss - Dartmouth CollegeKarsten Piepjohn - Federal Institute for Geosciences and Natural ResourcesSynnove Elvevold - Norwegian Polar InstituteGrzegorz Zielinska - Natl Res Inst, Polish Geol Inst, Microarea Anal Lab, Rakowiecka 4, PL-00975 Warsaw, PolandJaroslaw Majka - Uppsala University
- Resource Type
- Journal article
- Publication Details
- Canadian journal of earth sciences, Vol.60(8), pp.1188-1205
- Publisher
- Canadian Science Publishing
- DOI
- 10.1139/cjes-2022-0002
- ISSN
- 0008-4077
- eISSN
- 1480-3313
- Number of pages
- 18
- Grant note
- Norwegian Polar Institute 246130; 10101 / Arctic Field Grant 61.2899.1601.00.0 / Polish Geological Institute -NRI 2015/19/N/ST10/02646 / Polish National Science Centre (NCN)
- Language
- English
- Electronic publication date
- 03/22/2023
- Date published
- 08/2023
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984406592102771
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