EGU25-5614, updated on 14 Mar 2025
https://doi.org/10.5194/egusphere-egu25-5614
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Detrital zircon geochronology and the development of tectonic models for the Bohemian Massif
Stephen Collett
Stephen Collett
  • Czech Geological Survey, Prague, Czechia (stephen.collett@geology.cz)

Access to relatively rapid data acquisition techniques has led to detrital zircon geochronology becoming a routine and widely applied tool in provenance studies. These data, and their correlation, are applied both to paleographic reconstructions and the development of tectonic models. Nonetheless, the increasing proliferation of detrital zircon geochronological datasets and their haphazard integration into larger-scale correlations has led to a complex web of competing hypotheses and counter-hypotheses.

In order to formulate and test coherent hypotheses it is important to first establish a consistent framework in which these data can be properly assessed in both a temporal and geographical context. To this end, a database of U-Pb and Lu-Hf zircon isotopic data has been established from late Mesoproterozoic to late Paleozoic strata from Pangea-forming orogenic belts spanning from Atlantic North America through Europe, Northern Africa, the Middle East, and Central Asia to the Pacific Ocean. The original purpose of this database was to test correlations and various paleogeographical reconstructions in these regions during the transition from the Rodinia to Pangea supercontinent and a manuscript exploring these ideas and presenting the database is now published (Collett, 2025).

In this presentation, an extract from this database will be used to test several competing models on the pre-orogenic evolution of European Variscan Belt with specific focus on the Bohemian Massif. The Bohemian Massif is composed of four principal units, Saxothuringia, Teplá-Barrandia, Moldanubia, and Brunovistulia, which have in some tectonic models been considered to represent four distinct crustal blocks separated from one another by oceanic domains. Nonetheless, since oceanic domains should in theory act as barriers to the transportation of detritus and there are superficial similarities in detrital zircon spectra across these units; alternative models discarding one, or even all, of these oceanic domains have subsequently been proposed. However, the significance of these interpretations are hampered by either an incomplete or improper handling of the available data. In this presentation it will be demonstrated that detrital zircon data are actually supportive for, rather than an argument against, potential oceanic separation(s). This will be demonstrated by discussion of three key points: 1) The significance of Mesoproterozoic zircons in Brunovistulia, 2) the widespread occurrence of Stenian-Tonian age zircons in northern Gondwana and their distribution in the units of the Bohemian Massif, and 3) the relative abundance of Early Paleozoic zircons in northern Gondwana and the Bohemian Massif.

Collett, S. (2025). Detrital zircon tales between the Rodinia and Pangaea supercontinents; exploring connections between Avalonia, Cadomia and Central Asia. Journal of the Geological Society, 182(1), jgs2024-026.

How to cite: Collett, S.: Detrital zircon geochronology and the development of tectonic models for the Bohemian Massif, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5614, https://doi.org/10.5194/egusphere-egu25-5614, 2025.