Pre-Variscan basement elements of Central Europe appear in
polymetamorphic domains juxtaposed through Variscan and/or Alpine
tectonic events. Consequently, nomenclatures and zonations applied to
Variscan and Alpine structures, respectively, cannot be valid for
pre-Variscan structures. Comparing pre-Variscan relics hidden in the
Variscan basement areas of Central Europe, the Alps included, large
parallels between the evolution of basement areas of future Avalonia and
its former peri-Gondwanan eastern prolongations (e.g. Cadomia,
Intra-Alpine Terrane) become evident. Their plate-tectonic evolution
from the Late Proterozoic to the Late Ordovician is interpreted as a
continuous Gondwana-directed evolution. Cadomian basement, late Cadomian
granitoids, late Proterozoic detrital sediments and active margin
settings characterize the pre-Cambrian evolution of most of the
Gondwana-derived microcontinental pieces. Also the Rheic ocean,
separating Avalonia from Gondwana, should have had, at its early stages,
a lateral continuation in the former eastern prolongation of
peri-Gondwanan microcontinents (e.g. Cadomia, Intra-Alpine Terrane).
Subduction of oceanic ridge (Proto-Tethys) triggered the break-off of
Avalonia, whereas in the eastern prolongation, the presence of the ridge
may have triggered the amalgamation of volcanic arcs and continental
ribbons with Gondwana (Ordovician orogenic event). Renewed
Gondwana-directed subduction led to the opening of Palaeo-Tethys.