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| TRAVERSA,GIANBOSCO; GOMES,CELSO B.; BROTZU,PIERO; BURAGLINI,NICOLETTA; MORBIDELLI,LUCIO; PRINCIPATO,MARIA SPERANZA; RONCA,SARA; RUBERTI,EXCELSO. |
| The Araxá complex (16 km²) comprises carbonatites forming a central core and a complex network of concentric and radial dykes as well as small veins; additionally, it includes mica-rich rocks, phoscorites and lamprophyres. Fenites also occur and are represented by Proterozoic quartzites and schists of the Araxá Group. The petrographic study of 130 borehole samples indicates that the complex is basically made up by two rock-types, carbonatites and mica-rich rocks, and subordinately by a third unit of hybrid composition. Carbonatites range chemically in composition, the most abundant type being magnesiocarbonatites. Dolomite and calcite correspond to the chief constituents, but other carbonate phases, including the Ce-group RE minerals, are also recognized.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Alkaline rocks; Carbonatites; Geochemistry. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652001000100008 |
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