Donnees nouvelles sur l'Antecambrien dans l'ouest de la France; Pentevrien et Brioverien en baie de Saint-Brieuc (Cotes-du-Nord)

Abstract

The ophiolitic Erquy series, representing the base of the Brioverian in Brittany, France, rests discordantly on a crystalline complex of granite-gneiss, amphibolites, and dioritic migmatites. Later metamorphism has affected both basement and cover and tends to obscure their relationships. The name Pentevrian is proposed for the pre-Brioverian complex at the base of the series (represented by arkoses and conglomerates in places). Its exact age is not known, as is also the case with the lower Brioverian which also is probably Precambrian.