Fig. 6

Illustration of combined diagrams including probability density plots (gray shaded), frequency histograms (red) and kernel density estimations (blue) of ²⁰⁶Pb/²³⁸U ages (<1 Ga) and ²⁰⁷Pb/²⁰⁶Pb ages (>1 Ga), respectively, for the metasedimentary samples 618 (a) and 644 (b). Plots were created using the DensityPlotter of Vermeesch (2012). Diagrams indicate age distribution of concordance-filtered data at >90 %. The dashed line marks the maximum depositional age for both samples at ~490 Ma. Younger ages correspond to either bright rims or newly formed zircons, grown during Carboniferous to Permian magmatometamorphic events. In the lowest row, periods of increased crustal growth detected within the Central European basement units (Gebauer et al. 1989) and important detrital age populations from the northern Gondwana mainland (Meinhold et al. 2013) are depicted for comparison