Cadomian massifs in central Europe show distinct deposits of glacial origin which can either be assigned to the Upper Ediacaran Glacial Period (UEGP) at ca. 565 Ma or to the Hirnantian glaciation (HG) at ca. 445 Ma. On the other hand, coeval massifs of East Avalonia show no glacial deposits. Detrital zircon U–Pb analyses of selected Cadomian tillites were compared with data representing Avalonia and the main crustal units Laurentia, Baltica and the West African Craton (N Gondwana). The results demonstrated that the detrital zircon patterns confirm the drift-off of the Avalonian terranes during the late Ordovician towards the North until their collision with Baltica and Laurentia in Silurian times. The Cadomian terranes never left the northern periphery of Gondwana and remained in higher latitudes for a much longer time, experiencing glacial cover and deposition. During the late Devonian Famennian glaciation (FG) both terrane assemblages show no glacial influence, except the occurrence of a sandstone unit which is interpreted as lowstand deposits due to glacial-induced sea level fall. These sandstone samples are characterised by very different detrital zircon age spectra, allowing the interpretation, that the Rheic Ocean was still open, acting as sedimentary sink and separating the northern Laurentia-Baltica zircon province on Avalonia from the southern Gondwana zircon province on Cadomia. The presented data reflect how the knowledge about the influence of glacial conditions on sedimentary units of East Avalonia and Cadomia prior to their Variscan collision can help to unravel the affiliation of crustal units within the remnants of the now chaotic Variscan Orogen.