Geologia, petrologia e metalogenia da sequência vulcano-sedimentar de Alpinopolis, Minas Gerais

Carvalho, Sebastião Gomes de; Barbour, Aledir Paganelli

doi:10.11606/t.44.1990.tde-22062015-150049

Cited by 6 publications

(16 citation statements)

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“…(Teixeira et al 1987, Carvalho et al 1993. Este substrato é intrudido por corpos circunscritos de metatonalitos e granitos, além de diques máficos e metamáficos diversos.…”

Section: Ortognaisse Campos Geraisunclassified

Litogeoquímica do Complexo Campos Gerais e granitoides intrusivos, Arqueano/Paleoproterozoico, Brasil

Turbay

Valeriano

2012

Rev. bras. geociênc.

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“…(Teixeira et al 1987, Carvalho et al 1993. Este substrato é intrudido por corpos circunscritos de metatonalitos e granitos, além de diques máficos e metamáficos diversos.…”

Section: Ortognaisse Campos Geraisunclassified

Litogeoquímica do Complexo Campos Gerais e granitoides intrusivos, Arqueano/Paleoproterozoico, Brasil

Turbay

Valeriano

2012

Rev. bras. geociênc.

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“…This volcanic complex overlies a sequence of phyllites and lenticular quartzites of Late Devonian age and is overlain, with local disconformities, by flysch deposits ranging from the Visean to the Namurian -Lower Westphalian stage ( and Oliveira, 1979 Carvalho, 1979). Carvalho (1979) has distinguished three main groups of deposits ( Fig. 2): the rooted or proximal type, the transition type and the rootless or distal type.…”

Section: The Sulfide Ore Bodiesmentioning

confidence: 99%

Seafloor Volcanism and Polymetallic Sulfide Deposits in Ancient Active Margins: The Case of the Iberian Pyrite Belt

Monteiro¹,

Carvalho²

1987

Marine Minerals

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ABSTRACT. Massive polymetallic sulfide deposits occur throughout the Iberian Pyrite Belt. The mineralization is related to submarine felsic volcanism that took place during the Upper Devonian-Lower Carboniferous evolution of the South Portuguese Zone. The geotectonic setting of the IPB is reexamined taking into account the results from active margin drilling under Deep Sea Drilling Program/IPOD. Changes of the mode of subduction from M-type to C-type, appears to be a reasonable model for the geological conditions prevailing at the IPB. It is suggested that the link between field geology and geochemical studies carried in ancient subduction complexes coupled with the studies of modern analogs, allows a better understanding of convergent margins and their ore deposits.

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“…Com exceção da última unidade, as demais hospedam concentrações de sulfeto (principalmente piríta e pirrotita; subordinadamente calcopiríta, pentlandita e esfaleríta), que podem formar corpos mineralizados a Ni-Fe de até quatro metros de espessura (Carvalho 1990).…”

unclassified

“…A textura spinifex pseudomorfisada é marcada por cristais aciculares de actinolita e/ou tremolita, clorita e, secundariamente, por hornblenda ou actinolita (Prancha l -Fotomicrografia 1). A olivina reliquiar forma cristais corroídos irregulares a ovóides e é constituída, principalmente, por crisolita e hialosiderita, e a clorita por penina e clinocloro (Prancha l -Fotomicrografia 2) (Carvalho 1990).…”

unclassified

“…O primeiro e mais abundante eqüivale a clorita-tremolita serpentinito (Prancha 2 -Fotomicrografia 3) e o segundo a carbonato serpentinito (Prancha 2 -Fotomicrografia 4), sendo que em ambos ps tipos é possível observar restos de olivinas. Nos dois litotipos, o mineral de serpentina dominante é a lizardita, enquanto o anfibólio corresponde à tremolita e secundariamente à hornblenda (Carvalho 1990). Os minerais de clorita são representados essencialmente por clinocloro.…”

unclassified

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Geologia Da Seqüência Vulcano-Sedimentar De Alpinópolis (Mg)

Carvalho

SOARES

Antônio

et al. 1993

RBG

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GEOLOGY OF THE ALPINÓPOLIS VOLCANO-SEDIMENTARY SEQUENCE, MINAS GERAIS. The Alpinópolis Belt is located in the southern part of the State of Minas Gerais. It is one of several meta volcano-sedimentary sequences of the Morro do Ferro Greenstone Belt. As a result of surface geological mapping, petrological studies and subsurface exploration work conducted on the Alpinópolis region, a group of four rock suites have been recognized. The most important features of these four rock suites can be summarized as follows: The first suite comprises (a) chlorite-actinolite-tremolite schists with spinifex texture and minor olivine pseudomorphous; and (b) serpentinites with variable proportions of actinolite-tremolite-chlorite-talc-oli vine relicts and hornblende schists. The combined evidence of mineral assemblages, preserved primary textures and trace element chemistry indicate that these rocks were originally peridotites and pyroxenites of komatiitic affiliation. The second suite consists of a variable assemblage of plagioclase-homblende-actinolite-tremolite schists and amphibolites. The chemical and mineralogical features of this suite are consistent with a tholeiitic basalt origin. The third suite consists of metasedimentary rocks such as gamet-biotite schists, actinolite-tremolite-biotite schists, sillimanite-staurolite-biotite schists, gamet-antophylite schists, quartzites and minor iron formation units. The schists are interpreted to be isochemically metamorphosed tuffaceous, argillaceous and impure Fe-Mg-carbonate sediments. The aforementioned supracrustal rocks have been intruded by a number of granitoid rocks that consist of quartz, sódic-plagioclase and biotite. Near to and at the contact with the ultramafic flows, marundite rocks are observed. The policyclic tectonic-metamorphic and deformational processes which affected the area have given place to a complex, large scale structurally deformed framework and imprinted metamorphic patterns on the existing rock units and the associated Ni-sulphide ore bodies.

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Geologia, petrologia e metalogenia da sequência vulcano-sedimentar de Alpinopolis, Minas Gerais

Cited by 6 publications

References 0 publications

Litogeoquímica do Complexo Campos Gerais e granitoides intrusivos, Arqueano/Paleoproterozoico, Brasil

Litogeoquímica do Complexo Campos Gerais e granitoides intrusivos, Arqueano/Paleoproterozoico, Brasil

Seafloor Volcanism and Polymetallic Sulfide Deposits in Ancient Active Margins: The Case of the Iberian Pyrite Belt

Geologia Da Seqüência Vulcano-Sedimentar De Alpinópolis (Mg)

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