Avalonia, Armorica, Perunica: terranes, microcontinents, microplates or palaeobiogeographical provinces?

Abstract

AbstractIn recent decades various research studies have focused on the reconstruction of Palaeozoic Europe, reflecting the complex geodynamic history related to the formation of the supercontinent Pangaea. It has been demonstrated that Palaeozoic Europe comprises a series of tectonostratigraphical units, or ‘terranes’, located between the remnants of three major palaeocontinents, Gondwana, Laurentia and Baltica. Some of these ‘terranes’ have been referred to as ‘microcontinents’, a typical (palaeo-)geographical term, and as ‘microplates’, a typical plate-tectonic term, giving rise to misunderstandings and a continuing scientific debate. This confusion is based primarily on an inconsistent use of different palaeogeographical terms by specialists from different scientific disciplines. Whereas large palaeocontinents such as Baltica and Siberia have been named as terranes by some workers, several peri-Gondwanan ‘terranes’ have been attributed to microcontinents or microplates, without conclusive reasoning. This paper is a critical review of the terminology used for three European peri-Gondwanan palaeogeographical entities: ‘Avalonia’, ‘Armorica’ and ‘Perunica’. The review indicates that only Avalonia should be considered as a separate (micro-)continent on a separate (micro-)plate. Armorica has many different definitions and is commonly considered to be composed of several terranes. It is, however, not at all evident if Armorica was a separate (micro-)continent and/or an independent (micro-)plate. For Perunica, defined originally as a separate microplate, current evidence demonstrates that it can probably be considered only as a palaeobiogeographical province.