Tectonic history of the Hercynian Armorican Shear belt (Brittany, France)

Abstract

The Hercynian Armorican belt is made of different tectonic domains separated by large-scale shear zones. One of these domains, Central Brittany, was deformed by regional pervasive dextral strike-slip during Carboniferous times. This paper examines implications that the restoration of ductile strain within Central Brittany has on the deformation history along its boundaries and within adjacent domains. Data used for the analysis include surface structural features and recent deep seismic data. A good consistency is observed between model implications and available geological and structural data. Results lead to a reappraisal of the Carboniferous history of the Armorican belt, including relationships between tectonics, plutonism and basin development. They further emphasize the usefulness of restoration for integrated tectonic analysis of crustal-scale deformation zones.