Journal article
Middle Cambrian convergence at the southwestern Baltica margin, Holy Cross Mts., Poland, and its significance for reconstructions of early Gondwana
GEOSCIENCE FRONTIERS, Vol.16(2), 101972
03/2025
DOI: 10.1016/j.gsf.2024.101972
Abstract
The western periphery of Baltica has traditionally been viewed as a passive continental margin formed during the fragmentation of Rodinia and the opening of the Iapetus and Tornquist Oceans. This view is supported by the Volyn Large Igneous Province (VLIP) of Ediacaran age in Eastern Europe, which may be associated with break-up and evolution of the Tornquist Ocean. However, in western Ukraine, the sedimentary succession overlying the VLIP contains latest Ediacaran to early Cambrian detrital zircon with mixed εHf(t) values that can be interpreted to reflect deposition in a convergent margin setting with input from a continental volcanic arc. To investigate the potential convergent tectonic setting along SW Baltica during the Ediacaran to Cambrian transition, we conducted research in the Holy Cross Mts. (HCM), Poland. Here, tightly folded, and low-grade metamorphosed slates are unconformably overlain by Lower Ordovician (Tremadocian) sedimentary rocks. We applied 40Ar/39Ar geochronology on white mica defining cleavage in lower Cambrian rocks and U-Pb geochronology on detrital zircons to constrain the timing of the deformation. Our samples show similar populations of detrital zircons, with affinities to regions within or on the outskirts of Baltica. For all Cambrian samples, the calculated maximum depositional age is close to their stratigraphic age, suggesting rapid deposition in an active tectonic setting. The εHf(t) values range from −18 to + 12 indicating significant mixing of mantle-derived magmas with mature crustal material typical of continental magmatic arc systems. Single-grain fusion 40Ar/39Ar geochronology on white mica yielded two populations of weighted average ages of 537 ± 1 Ma and 510 ± 4.4 Ma, interpreted as a detrital white mica population and the maximum approximation of the age of post-depositional early to middle Cambrian deformation, respectively. The similarities in zircon populations and isotopic compositions between Cambrian sediments of the HCM and those from Ukraine, suggest that both areas were sourced from a continental arc on the Baltica margin, above a subduction zone consuming Neoproterozoic Mirovoi Ocean crust. This arc is likely an equivalent to the Cadomian Arc on the opposite side of the ocean.
Details
- Title: Subtitle
- Middle Cambrian convergence at the southwestern Baltica margin, Holy Cross Mts., Poland, and its significance for reconstructions of early Gondwana
- Creators
- Riccardo Callegari - Uppsala UniversityStanisław Mazur - Polish Academy of SciencesWilliam C. McClelland - University of IowaChristopher J. Barnes - Polish Academy of SciencesGrzegorz Ziemniak - University of WrocławKarolina Kośmińska - AGH University of KrakowJarosław Majka - AGH University of Krakow
- Resource Type
- Journal article
- Publication Details
- GEOSCIENCE FRONTIERS, Vol.16(2), 101972
- Publisher
- CHINA UNIV GEOSCIENCES, BEIJING
- DOI
- 10.1016/j.gsf.2024.101972
- ISSN
- 1674-9871
- eISSN
- 2588-9192
- Grant note
- National Science Centre (Poland), IAPETUS: 2019/33/B/ST10/01728 NSF: EAR-2050246
This work was funded by the National Science Centre (Poland), IAPETUS project no. 2019/33/B/ST10/01728 to J. Majka. The Arizona Laserchron Facility is supported by NSF grant EAR-2050246. The authors are thankful to K. Walczak (AGH University of Krakow) for her support during the zircon separation, to Mathew Domeier (Associate Editor), Brendan Murphy and Jerzy Nawrocki for the valuable revisions increasing the quality of this publication.
- Language
- English
- Electronic publication date
- 11/2024
- Date published
- 03/2025
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984752556602771
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