2 documents found, page 1 of 1
Petrology of the tephrite-phonolite suite and cognate xenoliths of the Fortalez...
Macciotta, Giampaolo; Almeida, Afonso; Barbieri, Mario; Beccaluva, Luigi; Brotzu, Piero; Coltorti, Massimo; Conte, Aida; Garbarino, CarloThe alkaline district of Fortaleza (Cearä, Brazil) consists of a number of phonotephritic plugs, domes, and dykes cropping out in the Precambrian basement, aged around 30 Ma.Chemically and petrographically the rocks range in composition from tephrites and phonolitic tephrites to peralkaline phonolites. At one locality (Caruru), olivine clinopyroxenite, essexite, and nepheline syenite xenoliths of cognate origin...
Mantle sources and differentiation of alkaline magmatic suite of Lages, Santa C...
Traversa, Gianbosco; Barbieri, Mário; Beccaluva, Luigi; Coltorti, Massimo; Conte, Aida Maria; Garbarino, Carlo; Gomes, Celso B; Macciotta, GiampaoloArtigo; The alkaline-carbonatite district of Lages (Santa Catarina, Brazil), contains mafic-ultramafic and prevalent leucocratic bodies mainly composed of olivine melilitites, olivine nephelinites, basanites, phonotephrites, nepheline syenites and peralkaline phonolites. Kimberlitic pipe breccias and carbonatitic rocks are also present. Petrography, mineral and bulk-rock chemistry and mass balance calculations ...