Journal article
Detrital zircon geochronology of lower Palaeozoic sedimentary rocks from the COSC-2 borehole, Scandinavian Caledonides
Geoscience Frontiers, Vol.16(4), 102077
07/2025
DOI: 10.1016/j.gsf.2025.102077
Abstract
Detrital zircon geochronology is reported from the c. 1200 m thick Cambro-Ordovician sedimentary succession recovered in core from the COSC-2 continental drilling project in the Scandinavian Caledonides. Above a regolith marking the sub-Cambrian peneplain, a lower to middle Cambrian(?) succession comprises conglomerate, sandstone and shale overlain by gravity flows fining upwards into the Alum Shale Formation. First results of detrital zircon geochronology from the Cambrian(?) succession show that the basal section of the autochthonous cover is characterized by mainly late Paleoproterozoic – early Mesoproterozoic detrital grains. The middle part of the succession is dominated by late Paleoproterozoic detritus with minor Mesoproterozoic and Archean input. The upper part of lower Cambrian(?) succession is characterized by Archean to Cambrian detritus. The maximum depositional age is calculated to 530.5 ± 4 Ma for the upper part of the lower Cambrian succession. Two samples from the Lower Ordovician(?) succession above the Alum Shale Formation show predominantly Mesoproterozoic to early Neoproterozoic (1.5–0.9 Ga) ages.
The autochthonous lower Cambrian(?) passive margin succession in the lower section is dominated by local detritus, sourced exclusively from the Eastern Segment of the Sveconorwegian Orogen which includes the basement studied in COSC-2. Up-section, the provenance shifts towards the Transscandinavian Igneous Belt and Svecofennian Orogen sources, with the youngest part of the succession showing a notable input of Neoproterozoic –Cambrian active margin detritus. The Ordovician(?) succession is characterized by populations, likely derived from the Sveconorwegian Orogen, and a minor cratonic contribution.
Statistical analysis of detrital zircon datasets across Baltica suggests that the Southern Baltica/Sandomirian Arc, rather than the Timanian Orogen, was a significant source of detrital material across the paleocontinent. The influence of Timanian Orogen grains is limited to northernmost Scandinavia, whereas Sandomirian detritus reached central Scandinavia in the lower to middle Cambrian and remained prevalent in southern Scandinavia into the Lower Ordovician.
Details
- Title: Subtitle
- Detrital zircon geochronology of lower Palaeozoic sedimentary rocks from the COSC-2 borehole, Scandinavian Caledonides
- Creators
- Grzegorz ZiemniakIwona KlonowskaWilliam C. McClellandOliver LehnertSimon CuthbertIsabel CarterRiccardo CallegariKatarzyna Walczak
- Resource Type
- Journal article
- Publication Details
- Geoscience Frontiers, Vol.16(4), 102077
- DOI
- 10.1016/j.gsf.2025.102077
- ISSN
- 1674-9871
- eISSN
- 2588-9192
- Publisher
- CHINA UNIV GEOSCIENCES, BEIJING; HAIDIAN DISTRICT
- Grant note
- National Science Centre (NCN, Poland): 2018/29/B/ST10/02315, 2019/33/B/ST10/01728 Swedish Research Council (Vetenskapsradet): 2019-03688 Deutsche Forschunggemeinschaft: 867/12-1, 13-1, 13-2 National Science Foundation (USA): EAR2050246
The COSC-2 borehole was drilled with the Swedish national research infrastructure for scientific drilling, "Riksriggen". We are thankful to the entire COSC drilling and scientific teams led by Henning Lorenz. This work was funded by the National Science Centre (NCN, Poland) project nos. 2018/29/B/ST10/02315 and 2019/33/B/ST10/01728 and the Swedish Research Council (Vetenskapsradet) grant no. 2019-03688. OL is grateful to the Deutsche Forschunggemeinschaft for the support of his COSC-2 research (DFG 867/12-1, 13-1, and 13-2) . The Arizona Laserchron Facility is supported by a National Science Foundation (USA) grant EAR2050246. We thank Bernard Bingen and an anonymous reviewer for constructive reviews and Mathew Domeier for editorial handling.
- Language
- English
- Electronic publication date
- 05/2025
- Date published
- 07/2025
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984824297202771
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