The mafic-silicic layered intrusions of Saint-Jean-du-Doigt (France) and North-Guernsey (Channel Islands), Armorican Massif: Gabbro-diorite layering and mafic cumulate-pegmatoid association

► The SJIC and NGIC are mafic-silicic layered intrusions in the Armorican Massif. ► At some stages, both were mafic reservoirs invaded by intermediate magmas. ► Layering can result from spreading of dioritic magma within a crystallizing gabbro. ► Extraction of late diapirs results in cumulative textures in dioritic layers. ► Associated pegmatoids correspond to liquids issued from a mafic intercumulus melt.