Palaeozoic history of the Armorican Massif: Models for the tectonic evolution of the suture zones

Abstract

The Armorican Massif (western France) provides an excellent record of the Palaeozoic history of the Variscan belt. Following the Late Neoproterozoic Cadomian orogeny, the Cambro-Ordovician rifting was associated with oceanic spreading. The Central-and North-Amorican domains (which together constitute the core of the Armorica microplate) are bounded by two composite suture zones. To the north, the Léon domain (correlated with the ''Normannian High'' and the ''Mid-German Crystalline Rise'' in the Saxo-Thuringian Zone) records the development of a nappe stack along the northern suture zone, and was backthrusted over the central-Armorican domain during the Carboniferous. To the south, an intermediate block (''Upper Allochthon'') records a complex, polyorogenic history, with an early high-temperature event followed by the first generation of eclogites (Essarts). This intermediate block overthrusts to the north the Armorica microplate (Saint-Georges-sur-Loire), to the south: (i) relics of an oceanic domain; and (ii) the Gondwana palaeomargin. The collision occurred during a Late Devonian event, associated with a second generation of eclogites (Cellier). To cite this article: M.

Magmatic and hydrothermal behavior of uranium in syntectonic leucogranites: The uranium mineralization associated with the Hercynian Guérande granite (Armorican Massif, France)

“…The southern part of the Armorican Massif belongs to the internal zone of the Hercynian belt in Western Europe and results from the collision of the Gondwana supercontinent with the Armorica microplate (Ballèvre et al, 2009). The South Armorican Massif is bounded to the north by the South Armorican Shear Zone (SASZ) (Fig.…”

Pressure solution in rocks: focused ion beam/transmission electron microscopy study on orthogneiss from South Armorican Shear Zone, France

“…The South Armorican Shear Zone (SASZ) in European Variscides represents a major tectonic zone dividing the Central Armorican and the South Armorican Massif in France (Ballèvre et al 2009;Fig. 1a).…”

Heavy-mineral, mineral-chemical and zircon-age constraints on the provenance of Triassic sandstones from the Devon coast, southern Britain

“…Variscan granites are widespread in the Armorican Massif of northern France and equivalent parts of the Variscan mountain belt in central Europe (Tischendorf et al, 1995;Brown & Dallmeyer, 1996;Ballèvre, 2009;Tyrrell et al, 2012). These granites are known to have been available as a sediment source as early as the Late Carboniferous, on the basis of the presence of detrital zircons in Westphalian sandstones of the UK (Hallsworth et al, 2000;Morton et al, 2010), and on the basis of evidence for rapid exhumation of such granites in the Variscan mountain belt (Schulmann et al, 2002).…”