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 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.

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 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.

Targeting Iron Ore in Banded Iron Formations Using ASTER Data: Weld Range Greenstone Belt, Yilgarn Craton, Western Australia

2012 ◽  
Vol 107 (4) ◽  
pp. 585-597 ◽  
Author(s):  
P. Duuring ◽  
S. G. Hagemann ◽  
Y. Novikova ◽  
T. Cudahy ◽  
C. Laukamp
Keyword(s):  
Western Australia ◽  
Greenstone Belt ◽  
Iron Ore ◽  
Yilgarn Craton ◽  
Banded Iron Formations ◽  
Aster Data ◽  
Iron Formations
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