Perambu is a peralkaline granite intrusion which cuts Precambrian gneisses and migmatites along its northern margin, but in the south is in contact with molasse-type sediments and associated volcanics. The granite contains biotite, aegirine and a little riebeckite. Associated peralkaline dykes are very numerous, particularly in the gneiss terrain to the north, and contain aegirine, riebeckite and arfvedsonite. Very little information is available.
SA, E.F.J, de, 1981. A orogenese Brasiliana e suas relacoes com faixas supracrustais no sudoeste do Ceara. Atas do X Simposio de Geologia do Nordeste. Recife: 337-50