Roberto Dall’Agnol

Universidade Federal do Pará

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Prafulla Kumar Sahoo

Central University of Punjab

Gabriel Negreiros Salomão

Vale Technological Institute

Cláudio Nery Lamarão

Universidade Federal do Pará

Davis Carvalho de Oliveira

Universidade Federal do Pará

Pedro Walfir Martins e Souza Filho

Vale (Brazil)

Moacir José Buenano Macambira

Universidade Federal do Pará

José Tasso Felix Guimarães

Vale (Brazil)

Régis Munhoz Krás Borges

Universidade Federal do Pará

José de Arimatéia Costa de Almeida

Harefield Hospital

Hilton Túlio Costi

Museu Paraense Emílio Goeldi

Cooperative Institutions

Universidade Federal do Pará

Vale Technological Institute

Vale (Brazil)

Instituto de Geociencias

Universidade de São Paulo

National Council for Scientific and Technological Development

Instituto de Desenvolvimento Sustentável Mamirauá

Centre National de la Recherche Scientifique

Universidade de Brasília

Serviço Geológico do Brasil - CPRM

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DEFORMAÇÃO DE ROCHAS GRANITÓIDES EM REGIME DÚCTIL: O EXEMPLO DO GNAISSE ESTRELA, REGIÃO DE CARAJÁS

Brazilian Journal of Geology (1994)

Carlos E.M. Barros Roberto Dall’Agnol

The Estrela Gneiss is an Archaean gneiss-granitic body that outcrops to the east of the Serra dos Carajas. Detailed microscopic studies of these gneisses and deformed pegmatoid rocks revealed several microstructures in grains of quartz, feldspars and mafic minerals, indicating plastic flow during deformation. The microstructural features appear firstly in quartz, afterwards they are observed in K-feldspars and finally in plagioclase. The evolution of these microstructures follows the sequence: 1. wavy extinction; 2. kink bands; 3. sub-grains; 4. new grains; 5. wavy extinction in new grains; and 6. cyclic recrystallization. During the stages 1 and 2 recovery mechanisms are more important, however, when dynamic recrystallization is present, mechanisms of sub-grain rotation and grain boundary migration start to act. The interaction of these processes account for a global plastic behavior and the rheological contrasts between quartz and feldspars become negligible. The ductile behavior of feldspars suggests that shear zones developed under temperatures higher than 500°C.

Outcrop

10.5327/rbg.v24i1.499

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Citations (3)

Origin of the Archean leucogranodiorite–granite suites: Evidence from the Rio Maria terrane and implications for granite magmatism in the Archean

Lithos (2010)

José de Arimatéia Costa de Almeida Roberto Dall’Agnol Samantha Barriga Dias Fernando Jacques Althoff

Yilgarn Craton

10.1016/j.lithos.2010.07.026

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Citations (79)

Mineralogy, petrology, and origin of the Pedra Branca Suite: a tonalitic-trondhjemitic association with high Zr, Ti and Y, Carajás Province, Amazonian Craton

Brazilian Journal of Geology (2020)

Arthur Santos da Silva Gilmara Regina De Lima Feio João Paulo Silva Alves Roberto Dall’Agnol José de Arimatéia Costa de Almeida

The Pedra Branca suite (2.75 Ga) is located in the Canãa dos Carajás domain in the southeastern Amazonia Craton. It diverges from typical TTG in mineralogical and geochemical terms, by the presence of hornblende and clinopyroxene and because it has a high content of HFSE (Zr, Y, Ti, and Nb). It belongs to the low-K subalkaline series, which varies from metaluminous to peraluminous, and are mostly calc and ferroan granitoids. Amphibole is calcic and classified as ferroan-edenite, and hastingsite. Plagioclase is mainly oligoclase. The Fe/(Fe + Mg) ratios found in the amphiboles indicate that these granitoids were formed under high to moderate fO2 conditions. Geobarometric calculations suggest pressures between 9.3 and 71 Kbar for the origin and 4.8-53.4 Kbar for the emplacement. Geothermometric calculations suggest initial crystallization temperatures between 945 and 862°C, and the water content in the magma is estimated to be higher than 4 wt%. The magma source was defined as tholeiitic continental gabbro melted in an extensional setting (Carajás Rift) with geochemical features similar to diabase from Nova Canadá (PA). The Pedra Branca magma was originated by partial melting (~28%), leaving a residue with plagioclase (An40), hornblende, clinopyroxene, and may or may not have magnetite.

Hornblende

Amphibole

10.1590/2317-4889202020190093

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Statistical analysis of lake sediment geochemical data for understanding surface geological factors and processes: An example from Amazonian upland lakes, Brazil

CATENA (2018)

Prafulla Kumar Sahoo José Tasso Felix Guimarães Pedro Walfir Martins e Souza Filho Michael Powell Marcio Sousa da Silva

Lithology

Detritus

Parent rock

10.1016/j.catena.2018.12.003

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Citations (32)

IGCP project 510 — A-type Granites and Related Rocks through Time

Lithos (2007)

Carol D. Frost O RAMO Roberto Dall’Agnol

10.1016/j.lithos.2007.01.006

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Citations (25)

The Umarizal Igneous Association, Borborema Province, NE Brazil: Implications for the Genesis of A-Type Granites

Gondwana Research (2002)

Ian McReath Antônio Carlos Galindo Roberto Dall’Agnol

Hornblende

Fayalite

Fractional crystallization (geology)

10.1016/s1342-937x(05)70727-9

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Citations (16)

ESTUDOS DE MINERAIS OPACOS E SUSCETIBILIDADE MAGNÉTICA NOS GRANITOS MUSA E JAMON (REGIÃO DE RIO MARIA - SE DO PARÁ) E SUAS IMPLICAÇÕES PETROLÓGICAS

Brazilian Journal of Geology (1992)

Marilia Sacramento de Magalhães Roberto Dall’Agnol

Musa and Jamon granites represent Lower Proterozoic anorogenic magmatism of the Central Amazonian Province. Magnetite (Mt), ilmenite (Ilm), hematite (Ht) and goethite (Gt) are the opaque oxide minerals observed. Pyrite (Py) is the only sulfide described. Three Em types are distinguished: individual (I) Ilm - isolated crystals, composite (C) Ilm - crystals joinned to Mt, and trellis (T) Ilm - lamellae developped into the Mt. Titanomagnetite (TMt), I and C Ilm were the first crystallizing opaque minerals. Later, I Ilm was partially destabilized by titanite. During the subsolidus stage the oxidation-exsolution of TMt occurred, transforming this oxide into Mt+T Ilm. Partial hematitization of Mt and oxyhydration (Gt formation) had also occurred during this stage. Magnetic susceptibility (MS) values of the granites are high, and decrease with magmatic differentiation (amphibole facies → biotite facies → leucogranites). The high Mt contents justify the high MS values. Positive correlations among MS and modal contents of opaques, amphibole and the total of mafic minerals show that the earliest facies have the highest contents of the mentioned minerals, as well as of Mt. On the other hand, negative correlation is observed between chlorite (deuteric phase) and MS. Chlorite is enriched in the later facies in which the transformations are very important and the Mt is partially destabilized to Ht. Positive correlations are also observed among MS and Fe 2 O 3 , FeO, MgO and TiO 2 contents. The above characteristics and the Fe 2 O 3 /FeO ratios, generally high or near to one, allows to classify these granites into the Mt series. The titanite+Mt+quartz association and Fe 2 O 3 /FeO ratios indicate that relatively oxidizing conditions, probably, fO 2 conditions near to Ni-NiO buffer, prevailed during the evolution of Musa and Jamon granites.

Amphibole

Ilmenite

10.5327/rbg.v22i2.409

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Citations (12)

Mesoarchean sanukitoid rocks of the Rio Maria Granite-Greenstone Terrane, Amazonian craton, Brazil

Journal of South American Earth Sciences (2008)

Marcelo Augusto de Oliveira Roberto Dall’Agnol Fernando Jacques Althoff Albano Antônio da Silva Leite

Greenstone belt

10.1016/j.jsames.2008.07.003

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Citations (126)

Mineral chemistry and crystallization parameters of the A-type Paleoproterozoic Bannach Granite, Carajás Province, Pará, Brazil

Brazilian Journal of Geology (2018)

Caio José Soares Mesquita Roberto Dall’Agnol José de Arimatéia Costa de Almeida

The A-type Paleoproterozoic Bannach Granite belongs to the Jamon Suíte and cross-cut the Archean units of the Rio Maria Domain in the Carajás Province. It comprises eight facies with varied mafic content and texture: even-grained cumulate granite (CG), even coarse-grained biotite-amphibole monzogranite (cBAMz), even coarse-grained amphibole-biotite monzogranite (cABMz), porphyritic biotite monzogranite (pBMz), even coarse-grained leucomonzogranite (cLMz), early even medium-grained leucomonzogranite (EmLMz), late even medium-grained leucomonzogranite (LmLMz) and even fine-grained leucomonzogranite (fLMz). In the less evolved facies, the dominant amphibole is Fe-hornblende passing to Fe-edenite or hastingsite, with associated cummingtonite/grunerite originated from the destabilization of clinopyroxene. Biotite has ferroan composition and approaches annite in the late-emplaced leucomonzogranite. Plagioclase varies from andesine to oligoclase or from oligoclase to albite. Titanite, magnetite, and ilmenite are found in all granite facies showing magmatic origin. The near liquidus temperatures vary between 943ºC and 795ºC and the estimated emplacement pressure is 300 ± 50 MPa (~11.1 ± 1.9 km). Amphibole Fe/(Fe + Mg) ratios together with magmatic magnetite and titanite indicate that these granites crystallized at moderately oxidizing conditions, similar to those admitted for the Jamon granite and magnetite series granites of Laurentia. However, the composition of biotite suggests a more reduced character close to NNO to NNO -0.5. The late leucomonzogranite facies is an exception because it displays high Fe/(Fe + Mg) ratios in biotite and approaches to the reduced granites of Carajás, Laurentia and Fennoscandia in this regard. It derived from a more reduced source than the other facies of Bannach Granite.

Amphibole

Titanite

Porphyritic

Hornblende

Allanite

Laurentia

10.1590/2317-4889201820170082

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Citations (10)

Changes in the surface water quality of a tropical watershed in the southeastern amazon due to the environmental impacts of artisanal mining

Environmental Pollution (2023)

Gabriel Negreiros Salomão Roberto Dall’Agnol Prafulla Kumar Sahoo Gabriel Soares de Almeida Rafael Tarantino Amarante