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New constraints from detrital zircon U–Pb ages and whole-rock Nd isotope data on depositional ages and provenance of Neoproterozoic and Carboniferous greywackes of Saxony and adjacent regions (Saxo-Thuringia, Germany)

Upper Neoproterozoic sedimentary rocks anchored in the literature as greywackes are exposed in Saxo-Thuringia and represent the main sedimentary part of the Cadomian basement of the region with sedimentation ages between 540 and 570 Ma based on the youngest detrital zircon ages (e.g., Linnemann et al. 2000, Geol. Soc. Spec. Publ., 179, 131–153). Previous Nd model ages give a uniform old cratonic source of 1.5–1.9 Ga for the Neoproterozoic greywackes (Linnemann & Romer 2002, Tectonophysics, 352, 33–64). This study aims to re-examine the Cadomian greywackes of Saxony and adjacent areas by combining analytical methods, such as whole-rock Sm–Nd isotopic studies and detrital zircon U–Pb dating using LA-ICP-MS. The investigations have also been carried out comprehensively at locations not previously studied. Some Carboniferous greywackes were also sampled as a reference due to their similar appearance in the field and local uncertainties in their stratigraphic position. The new data are used to validate existing models of basin development and sedimentary provenance. The sedimentation of a large part of the Saxo-Thuringian clastic rocks along the periphery of Gondwana adjacent to the West African Craton in the Late Neoproterozoic could be proven. However, the youngest detrital zircons of around 490 Ma indicate that some units were deposited during the Late Cambrian to Early Ordovician and do not belong to the Cadomian rock units. Carboniferous samples show in addition Late Devonian zircon ages and Nd model ages younger than 1.5 Ga which points toward a different sedimentary provenance.

Details

Author
Victoria Kühnemann1, Guido Meinhold1, Sebastian Weber2, Matthias Willbold3, Armin Zeh4
Institutionen
1TU Bergakademie Freiberg, Germany; 2Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie (LfULG), Germany; 3Georg-August-Universität, Germany; 4Karlsruher Institut für Technologie (KIT), Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/99pp-mj05