Geochemistry and genesis of the banded iron formations of the Cauê Formation, Quadrilátero Ferrífero, Minas Gerais, Brazil

2007 ◽  
Vol 152 (3-4) ◽  
pp. 170-206 ◽  
Author(s):  
C SPIER ◽  
S DEOLIVEIRA ◽  
A SIAL ◽  
F RIOS
Keyword(s):  
Minas Gerais ◽  
Banded Iron Formations ◽  
Quadrilátero Ferrífero ◽  
Iron Formations

scholarly journals Associação entre valor cênico, turismo, religião e cultura na paisagem do Quadrilátero Ferrífero, Minas Gerais / Association between scenic value, tourism, religion and culture on the landscape (...)

2014 ◽  
Vol 24 (42) ◽  
pp. 198-218
Author(s):  
Luiz Eduardo Panisset Travassos
Keyword(s):  
Minas Gerais ◽  
Specific Region ◽  
Banded Iron Formations ◽  
Cultural Aspects ◽  
Brazilian Society ◽  
Iron Quadrangle ◽  
Quadrilátero Ferrífero ◽  
Initial Idea ◽  
Iron Formations ◽  
Scenic Value

A ideia para elaboração do presente trabalho surgiu a partir do convite da Sociedade Brasileira de Espeleologia para elaboração de um capítulo sobre o valor cênico, turismo e religião em regiões que apresentam cavernas desenvolvidas em formações ferríferas. A partir da ideia inicial, decidiu-se ampliar o tema para que pudéssemos incluir, também, aspectos culturais da paisagem em uma região específica como a do Quadrilátero Ferrífero (QF), em Minas Gerais. Assim, tem-se como objetivo principal da pesquisa demonstrar a possibilidade de associação entre o valor cênico, turismo, religião e cultura no QF por meio da indicação de exemplos selecionados. Palavras-chave: Valor cênico, turismo, religião, cultura, Quadrilátero Ferrífero ABSTRACTThe idea of this paper emerged after the invitation by the Brazilian Society of Speleology for preparation of a chapter on the scenic value, tourism and religion in regions with caves developed in banded iron formations. From the initial idea, the author decided to expand the theme here so one could include the cultural aspects of the landscape in a specific region such as the Iron Quadrangle (Quadrilátero Ferrífero), in Minas Gerais. Thus, the main objective of this study is to demonstrate the possible association between the scenic value of a landscape together with tourism, religion and culture by indicating selected examples, especially in the QF. Keywords: scenic value, tourism, religion, culture, Quadrilátero Ferrífero

scholarly journals A paleotoca da Serra do Gandarela e seu potencial como geossítio do Geoparque Quadrilátero Ferrífero, Minas Gerais / The paleoburrow of the Gandarela Mountains and its potential as a geosite of the QF Geopark, MG

2014 ◽  
Vol 24 (42) ◽  
pp. 249-263
Author(s):  
Úrsula Azevedo Ruchkys ◽  
Jonathas De Souza Bittencourt ◽  
Francisco Sekiguchi de Carvalho e Buchmann
Keyword(s):  
Preliminary Analysis ◽  
Minas Gerais ◽  
Quadrilátero Ferrífero ◽  
Paleontological Heritage ◽  
Iron Formations

A paleotoca registrada na Serra do Gandarela, Quadrilátero Ferrífero (MG), constitui um importante registro paleontológico da megafauna extinta de mamíferos, semelhante às ocorrências prévias em formações ferríferas no norte de Minas Gerais e em litologias diversas de outras regiões do país. Destaca-se pelas dimensões de 340m de comprimento, o que faz dela a maior paleotoca encontrada até o momento. Este trabalho, realizado sob os auspícios do Ministério Público de Minas Gerais, tem como objetivo avaliar o valor científico, pedagógico e educacional associado a esta ocorrência, visando sua inserção como geossítio do Geoparque Quadrilátero Ferrífero. Esta análise preliminar sugere que a paleotoca da Serra do Gandarela é um exemplo de patrimônio paleontológico com valores que legitimam plenamente sua proposição como sítio paleontológico/geológico do Geoparque Quadrilátero Ferrífero.Palavras-Chave: Paleotoca, megafauna extinta, Serra do Gandarela, Geoparque Quadrilátero Ferrífero. ABSTRACTThe paleoburrow in the Gandarela Mountains, Quadrilátero Ferrífero (MG) is an important record of the extinct megafauna of mammals. This is similar to previous occurrences in iron formations in northern Minas Gerais and in several rocks in other regions of Brazil, but stands out for the dimensions of length 340m, making it the largest paleoburrow found so far. This work has been carried out under the sponsorship of the Minas Gerais Public Prosecutor's Office. The scientific and educational significance of this fossil occurrence is assessed, aiming at its inclusion as a geosite of the Quadrilátero Ferrífero Geopark. This preliminary analysis suggests that this paleoburrow is a valuable example of paleontological heritage, what fully legitimates its proposition as a paleontological/geological site of Quadrilátero Ferrífero Geopark.Keywords: Paleoburrow, extinct megafauna, Gandarela Mountains, Quadrilátero Ferrífero Geopark. 

scholarly journals UM MODELO PARA A EVOLUÇÃO MICROESTRUTURAL DOS MINÉRIOS DE FERO DO QUADRILÁTEO FERRÍFERO. PARTE I - ESTRUTURAS E RECRISTALIZAÇÃO

1993 ◽  
Author(s):  
Carlos Alberto Rosière ◽  
Farid Chemale Jr. ◽  
Marcelo L.V. Guimarães
Keyword(s):  
Iron Ore ◽  
Banded Iron Formations ◽  
Lower Proterozoic ◽  
Ore Bodies ◽  
Quadrilátero Ferrífero ◽  
Textural Relationship ◽  
Iron Formations ◽  
Ore District ◽  
Proterozoic Age

In the Quadrilátero Ferrífero iron ore district, the Cauê Formation of the Minas Supergroup comprise banded iron formations, called itabirites, of Lower Proterozoic age enclosing iron rich ore bodies. Although many ore bodies are associated with syntectonic enrichment processes, due to the leaching of gangue minerals like quartz and carbonates, others are probably of sedimentary origin and were recrystallized during the tectonometamorphic development of the region.Three generations of magnetite and four of hematite are recognized in these rocks. They display a clear textural relationship in zones of high and low strain, with the development of two main deformational events under variable metamorphic conditions and different tectonic levels.The first part of this paper one describes the recrystallization phenomena and its relation to the main structures, while in the second part the developed textures and its association to the strain are presented.

scholarly journals Geochemical fingerprint of siliceous, amphibolitic and magnetitic itabirite types of the region of Serra Azul – Quadrilátero Ferrífero, MG

2015 ◽  
Vol 68 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Ana Ramalho Alkmim ◽  
Geraldo Magela Santos Sampaio ◽  
Júlia Cotta Maciel Dantas ◽  
Adriana Trópia de Abreu ◽  
Hermínio Arias Nalini Jr.
Keyword(s):  
Trace Elements ◽  
Rare Earth ◽  
The Other ◽  
Banded Iron Formations ◽  
Minor And Trace Elements ◽  
The Earth ◽  
Quadrilátero Ferrífero ◽  
Geochemical Fingerprint ◽  
Geochemical Investigation ◽  
Iron Formations

Banded iron formations are important providers of information about the evolution of the hydrosphere, atmosphere, biosphere and lithosphere of the Earth. This study gathers data from the geochemical investigation of major, minor and trace elements (including rare earth elements) of the siliceous, amphibolitic and magnetitic types of itabirite from the Cauê Formation, sampled in the Serra Azul region (Quadrilátero Ferrífero).Observing the trace elements described as tracers of detrital contamination can be inferred that the magnetitic itabirite has the highest contamination and that the siliceous type has the lowest one.Although there are differences in the total sum of REE in the three itabirite types of Serra Azul, there are no discrepancies in the REE spectrum of each type. The itabirite types have as common characteristics in their REE spectrum: i) positive Eu anomalies (Planavsky et al., 2010); ii) HREE enrichment in relation to the LREE; iii) ratios of (Sm/Yb)SN<1 and (Eu/Sm)SN>1 (Bau & Möller, 1993). The magnetitic and the siliceous itabirites had positive Y anomalies, a common characteristic that appeared in some amphibolitic samples. On the other hand, the other amphibolitic samples had negative Y anomalies.

Evidence for metre-scale variations in hematite composition within the Palaeoproterozoic Itabira Iron Formation, Minas Gerais, Brazil

2006 ◽  
Vol 70 (5) ◽  
pp. 591-602 ◽  
Author(s):  
A. R. Cabral ◽  
B. Lehmann ◽  
H. F. Galbiatti ◽  
O. G. Rocha Filho
Keyword(s):  
Chemical Composition ◽  
Spatial Relationship ◽  
Mineral Chemistry ◽  
Minas Gerais ◽  
Ore Deposits ◽  
Iron Formation ◽  
Quadrilátero Ferrífero ◽  
Iron Ore Deposits ◽  
Iron Formations ◽  
Gold Bearing

AbstractHematite is a mineral the chemical composition of which rarely differs significantly from stoichiometric Fe2O3. As such, little attention has been paid to the mineral chemistry of hematite in Precambrian iron formations, where hematite forms monomineralic high-grade orebodies. Electron microprobe analysis of hematite from two iron-ore deposits, Cauê (Itabira district) and Gongo Soco, in the Palaeoproterozoic Itabira Iron Formation, Quadrilátero Ferrífero of Minas Gerais, Brazil, has revealed distinct variations in chemical composition with respect to Ti and Cr. Hematite containing Ti and/or Cr is of very local occurrence in the itabirite unit and shows a spatial relationship to hematitic, palladiferous gold-bearing veins (known as ‘jacutinga’), occurring either within the veins (adjacent to, or included in, palladiferous gold grains) or in their vicinity. Where present, titaniferous hematite (to ∼1.3 wt.% TiO2) is lepidoblastic and defines a pervasive tectonic foliation (S1). In contrast, Ti-free, chromiferous hematite (to ∼6.4 wt.% Cr2O3) characteristically occurs as inclusions in palladiferous gold within S1-truncating ‘jacutinga’. Replacement of granoblastic, Ti-free, chromiferous martite with relicts of magnetite by lepidoblastic, Cr-depleted, titaniferous hematite proves that Cr and Ti were mobile during metamorphism. Chromium was ultimately fractionated into the hematite found in auriferous aggregates within cross-cutting ‘jacutinga’. A positive correlation between Cr and Pt in bulk-rock samples from the Itabira district suggests that Cr is a potential prospective guide for Au-Pd-Pt-bearing hematitic veins (‘jacutinga’).

scholarly journals ITABIRITOS E MINÉRIOS DE FERRO DE ALTO TEOR DO QUADRILÁTERO FERRÍFERO – UMA VISÃO GERAL E DISCUSSÃO

2000 ◽  
Author(s):  
Carlos A. Rosière ◽  
Farid Chemale Jr
Keyword(s):  
Banded Iron Formations ◽  
Tectonic Structures ◽  
Magmatic Origin ◽  
Tectonic Events ◽  
Deformational History ◽  
Ore Bodies ◽  
Quadrilátero Ferrífero ◽  
Supergene Processes ◽  
Iron Formations ◽  
Mineralizing Fluids

Itabirites are Palaeoproterozoic metamorphic banded iron formations from the Itabira Group, MinasSupergroup, that crop out in the Quadrilátero Ferrífero District, Minas Gerais, Brazil. The followingcompositional types occur: quartz itabirite, being metamorphic jaspilites, dolomitic itabirite, beingdolomitized banded iron formations, and amphibolitic itabirite modified by the presence of pelitic sediments.These rocks are also associated to pyritic phyllites and hematitic phyllites. A multiple metamorphic –deformational history during two main tectonic events, the Palaeoproterozoic Transamazonian and theNeoproterozoic Brasiliano Event, produced a variety of mineralogical assemblages in the more impurefacies and hydrothermal alteration was responsible for carbonatization, intensive oxidation and mineralization.Hypogenic iron mineralization developed in two main phases resulting in thick massive bodies with norelationship to tectonic structures, denominated non-tectonic ores; and schistose ore associated to shearzone, denominated syn-tectonic ores. The mineralizing fluids might be of metamorphic origin, but theimportance of hypogenic fluids of magmatic origin is emphasized. Supergene processes on quartz andspecially dolomitic itabirites are also of utmost importance in the development of giant ore bodies.

Biorremediação de solos contaminados com arsênio por meio de lavagem de solo usando biossurfactantes

2020 ◽  
Vol 25 (4) ◽  
pp. 543-553
Author(s):  
Ricardo Silva Coelho ◽  
Mônica Cristina Teixeira
Keyword(s):  
Soil Washing ◽  
Minas Gerais ◽  
Quadrilátero Ferrífero

RESUMO A mineração de ouro é uma das principais fontes de contaminação de arsênio (As) no Quadrilátero Ferrífero em Minas Gerais. O As é um elemento tóxico capaz de causar sérios danos à saúde humana. Com o objetivo de investigar formas mais ecológicas e igualmente eficientes para a remoção de As em solos, empregou-se a técnica de lavagem de solos (soil washing) com uso de extratos com biossurfactantes (BS) visando promover a mobilização do As contido em solo de mina de ouro abandonada. Para a produção dos extratos, foram selecionadas duas culturas mistas de bactérias produtoras de BS (MPCB e MPBR) tolerantes a alta concentração de arsênio (8 mg.L-1). Os tensoativos produzidos foram estáveis em ampla faixa de pH, 3-11; temperatura, 28-50ºC e salinidade, 1-5% NaCl (p.v-1). Nos testes de lavagem de solo, em pH 11, as remoções de As obtidas com os extratos MPCB (14,01 e 13,72%) e MPBR (12,04 e 12,31%) foram superiores àquelas obtidas com soluções a 1% (p.v-1) dos surfactantes comerciais SDS (0,87 e 0,71%); saponina (0,57 e 0,55%) e lecitina de soja (2,05 e 2,63%). Os resultados dos testes em coluna foram igualmente influenciados pelo pH e pela proporção sólido:líquido. As maiores remoções de As: 25,43% (MPCB) 22,43% (MPBR) foram obtidas em pH 11, na proporção 1:40 (g.mL-1), após 10 ciclos de extração. Os extratos MPCB e MPBR removeram o As solúvel em água, os íons ligados ao carbonato e aqueles adsorvidos. Ambos os extratos tiveram comportamento semelhante ao ácido etilenodiaminotetracético (EDTA) e ao extrato de cultura microbiana comercial (GorduraKlin®).

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