The Late Palaeozoic relations between Gondwana and Laurussia

Abstract

Reconstructions based on biogeography, palaeomagnetism and facies distributions indicate that, in later Palaeozoic time, there were no wide oceans separating the major continents. During the Silurian and Early Devonian time, many oceans became narrower so that only the less mobile animals and plants remained district. There were several continental collisions: the Tornquist Sea (between Baltica and Avalonia) closed in Late Ordovician time, the Iapetus Ocean (between Laurentia and the newly merged continents of Baltica and Avalonia) closed in Silurian time, and the Rheic Ocean (between Avalonia and Gondwana and the separate parts of the Armorican Terrane Assemblage) closed (at least partially) towards the end of Early Devonian time. Each of these closures was reflected by migrations of non-marine plants and animals as well as by contemporary deformation. New maps, based on palaeomagnetic and faunal data, indicate that Gondwana was close to Laurussia during the Devonian and Carboniferous periods, with fragments of Bohemia and other parts of the Armorican Terrane Assemblage interspersed between. It follows that, after Early Devonian time, the Variscan oceans of central Europe can never have been very wide. The tectonic evolution of Europe during Devonian and Carboniferous time was thus more comparable with the present-day Mediterranean Sea than with the Pacific Ocean.

Mississippian Platform and Basin Successions from the Todrha Valley (northeastern Anti‐Atlas), southern Morocco

“…Torsvik and Cocks (2004) showed a substantial Palaeotethys Ocean with northern Gondwana situated at ca 408 S and a greater than 108 latitudinal separation from southern Europe and eastern North America. In contrast, McKerrow et al (2000) and Matte (2001) showed minimal separation of these areas with Morocco at 208-308 S although the former noted that 'the northern margin of Africa was a barrier to plant migration'.…”

The Rhenohercynian passive margin of SW England: Development, inversion and extensional reactivation

“…The Rheic suture is also placed immediately south of SW England and is coincident with the Rhenohercynian suture in most tectonic reconstructions e.g. [62,64,97]. However, limited knowledge of both the pre-Devonian geology of SW England, and hence its Avalonian affinities, and the prePermian offshore geology between Britain and France results in considerable uncertainty.…”

“…No model accounts for all aspects and there are presently insufficient data to adequately test between them. Most palaeogeographical reconstructions consider a faunal barrier, implied to be the narrowed Rheic Ocean, persisted between Armorica and Avalonia during the Early Devonian e.g [64], which would mitigate against Model B. Early Devonian palaeomagnetic poles from South Wales (Lat.…”

Late- and post-Variscan cooling and exhumation history of the northern Rhenish massif and the southern Ruhr Basin: new constraints from fission-track analysis

“…Geologic framework and regional setting Tectonic processes during final stages of the Variscan orogeny caused a fundamental reorganisation of palaeogeography in Central Europe during late Palaeozoic times (e. g. McKerrow et al 2000;Tait et al 2000). The Variscan (Hercynian) fold-and-thrust belt extends from northwestern Spain, France, Britain and southwestern Ireland through central Germany into Poland in the east (Franke 2000).…”