Revisiting the (pre-Variscan) Galatia/Ligeria – Armorica terrane conception from an Austrian perspective

Abstract According to the original Galatia/Ligeria-Armorica terrane model, almost all pre-Variscan units in Austria (i.e., in the Alps as well as in the Bohemian Massif) were part of the Galatian/Ligerian microplate. We raise arguments against this interpretation based on a lithological and geochronological comparison of key regions (southern Bohemian Massif, Alps, Massif Central). We propose that the (non-Avalonian) parts of the southern Bohemian Massif actually belong to the Armorican microplate. A Trans-Mid-European belt of Upper Devonian ophiolite remnants and coeval primitive arc granitoids strikes from the northern Massif Central over the southern Vosges and the southern Black Forest onto the basement under the northern front of the Alps. It is interpreted as remnant oceanic and island-arc-type crust that marks the boundary between the Armorican and the Galatian/Ligerian terrane. Like most previous authors, we consider Armorica to be a Cadomian/Early Palaeozoic peri-Gondwana terrane that originated in the fore field of the Sahara metacraton and the West African craton. However, Galatia/Ligeria can be interpreted as Cadomian/Early Palaeozoic peri-Gondwana crust that formed farther east in front of the Arabian-Nubian Shield. After their Devonian off-drift from Gondwana, the two terranes approached each other and finally collided during the Variscan orogeny.