Location of the Rheic suture in the eastern Bohemian Massif: evidence from detrital zircon data

Abstract

Terra Nova, 24, 199–206, 2012AbstractThree detrital zircon concentrates from the metasediments of the Orlica‐Śnieżnik dome, Bohemian Massif, have been dated using Sensitive High Resolution Ion Microprobe. They yielded Precambrian age spectra similar to those that are characteristic of the Cadomian terranes: (1) Archaean and Palaeoproterozoic zircons scattered between 3380 and 1860 Ma, and (2) abundant Neoproterozoic zircons dated at 770–560 Ma. Two of the analysed samples also contain Early Cambrian and Early‐Late Cambrian zircons. The estimated maximum sedimentation ages are: 563 ± 6 Ma for the Młynowiec paragneisses, 532 ± 6 Ma for the Stronie schist and 490 ± 9 Ma for the Goszów quartzite that are interpreted as three distinct metasedimentary successions. They represent a Neoproterozoic back‐arc basin, Early Cambrian incipient rift basin and a Lower Ordovician post‐rift succession respectively. These successions are the deformed and metamorphosed, allochthonous equivalent to the passive Saxo‐Thuringian margin. They were subducted during a Variscan collision and then exhumed in front of the rigid buttress of Brunia/East Avalonia.