info:eu-repo/semantics/article
DISCUSSÃO DA GÊNESE DO PROTOMINÉRIO DE MANGANÊS DE FÁCEIS ÓXIDO- CARBONÁTICO DENOMINADOS "BANDARRITO", MUNICÍPIO DE JACARACI, BAHIA
DISCUSSÃO DA GÊNESE DO PROTOMINÉRIO DE MANGANÊS DE FÁCEIS ÓXIDO- CARBONÁTICO DENOMINADOS "BANDARRITO", MUNICÍPIO DE JACARACI, BAHIA
Autor
MACHADO, RÔMULO
Institución
Resumen
The Bandarra manganese deposit is located in the south portion of the State of Bahia within the volcano-sedimentary sequence of the supposed Licinio de Almeida greenstone belt. The lithologic units of the area consist, from base to top, of micaschists, iron-formation, micaschists, amphibolites and quartzites. Metamorphism reached the almandine-amphibolite facies. The ore bodies are lenticular layers within irom-formation and are made up of jacobsite, hausmannite, bixbyite, secondary manganese oxide (MnO2 group), hematite, carbonate with manganese, leghanyite, spessartite, tephroite and other manganiferous silicates. The coexistence of primary manganese oxides with carbonate in protore reflects different pH and Eh conditions from those of the classic metamorphic protores gondite and queluzite. For this reason the protore is here designated "bandarrite". The presence of native copper in the protore represents an uncommon association in manganese deposits. The Bandarra manganese deposit is located in the south portion of the State of Bahia within the volcano-sedimentary sequence of the supposed Licinio de Almeida greenstone belt. The lithologic units of the area consist, from base to top, of micaschists, iron-formation, micaschists, amphibolites and quartzites. Metamorphism reached the almandine-amphibolite facies. The ore bodies are lenticular layers within irom-formation and are made up of jacobsite, hausmannite, bixbyite, secondary manganese oxide (MnO2 group), hematite, carbonate with manganese, leghanyite, spessartite, tephroite and other manganiferous silicates. The coexistence of primary manganese oxides with carbonate in protore reflects different pH and Eh conditions from those of the classic metamorphic protores gondite and queluzite. For this reason the protore is here designated "bandarrite". The presence of native copper in the protore represents an uncommon association in manganese deposits.