Pyroxene
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Upper Cretaceous weakly to strongly silica-undersaturated alkaline dike series of the Mantiqueira Range, Serra do Mar alkaline province: Crustal assimilation processes and mantle source signatures
ABSTRACT: Three series of alkaline dikes are characterized in a restricted area of the Mantiqueira Range: a weakly silica-undersaturated series (normative ne < 7), of potassic character, represented by basanite, tephrites, alkali basalts, basaltic trachyandesites, phonotephrites, tephriphonolites, and trachyandesites, an intermediate series (7 > normative ne
Braz. J. Geol.. Publicado em: 2018-06
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2. Geology, geochemistry and petrology of basalts from Paraná Continental Magmatic Province in the Araguari, Uberlândia, Uberaba and Sacramento regions, Minas Gerais state, Brazil
Abstract: This study covers the region between the cities of Sacramento and Araguari/Uberlândia (Minas Gerais State, Brazil), where basalt flows from the Paraná Continental Magmatic Province outcrop. The investigated rocks present tholeiitic signature, with high titanium content, and are classified as Pitanga magma-type. The preserved basalt thickness is b
Braz. J. Geol.. Publicado em: 22/02/2018
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3. Serra Pelada: the first Amazonian Meteorite fall is a Eucrite (basalt) from Asteroid 4-Vesta
ABSTRACT Serra Pelada is the newest Brazilian eucrite and the first recovered fall from Amazonia (State of Pará, Brazil, June 29th 2017). In this paper, we report on its petrography, chemistry, mineralogy and its magnetic properties. Study of four thin sections reveals that the meteorite is brecciated, containing basaltic and gabbroic clasts, as well of rec
An. Acad. Bras. Ciênc.. Publicado em: 01/02/2018
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4. Mineralogy and petrology of microgranular enclaves of Poços de Caldas Alkaline Massifs nepheline syenites (MG-SP) / Mineralogia e petrologia de enclaves microgranulares de nefelina sienitos do Maciço Alcalino Poços de Caldas (MG-SP)
Os nefelina sienitos miasquíticos a intermediários do Maciço Alcalino Poços de Caldas (MAPC), em especial o tipo da Pedreira, possuem enclaves microgranulares félsicos e máficoultramáficos intrigantes. O nefelina sienito da Pedreira (NeS) pode ser divido em duas fácies texturais: uma de granulação média-grossa a grossa (NeS-g), outra de granulaç�
Publicado em: 2010
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5. Inclusões fluidas nos minerais associados a mineralização uranífera da jazida do Engenho (anomalia 09), Província Uranífea de Lagoa Real, Bahia / Fluid Inclusions in minerals associated to uranium mineralization in Engenho Deposit (anomaly 09) Lagoa Real Uranium Province Bahia
The Engenho deposit (anomaly 09) is south-eastern from Cachoeira Mine (anomaly 13), in the northern part of the Province. The uranium mineralization is associated to albitites (over 70% of albite/oligoclase). Epidosites with uranium may also occur. The albitite main minerals are pyroxene, garnet, albite/oligoclase feldspar, amphibole and biotite. Pyroxene, g
Publicado em: 2009
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6. Fatores condicionantes na gênese dos argilominerais dos folhelhos negros e pelitos associados da formação Irati no norte da bacia do Paraná
The Permian Irati Formation has an extensive distribution in the Paraná basin, and is frequently intruded by diabase sills. The heterogeneous geometry of the basin in the depositional time propitiated the development of different sedimentary facies in this unit and favored the deposition of terrigenous rocks in the south portion of the basin and carbonate a
Publicado em: 2008
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7. Petrologia da sucessão magmática do Arquipélago de Abrolhos
The Magmatic Succession of Abrolhoss Archipelago is composed by four units: Olivine-Plagioclase Basalt (b1), Pyroxene-Plagioclase-Olivine Basalt (b2), Pyroxene-Plagioclase Basalt (b3) and Cumulado (b4). The units are not stratigraphically correlated. They are stacked from the basis to the top in units: b1, b2, b3 and b4. The units of the magmatic succession
Publicado em: 2008
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8. Processos metalogenéticos em ambientes de arco magmático tipo andino, caso de estudo: mineralizações da região dos Andes Patagônicos setentrionais do Chile / Metallogenic processes in andean volcanic arc setting, study case: mineralizations in the Chilean North-Patagonion Andes
In the Patagonian Andes region between 41 and 44° S extensive and continuous plutonic rocks of the North-Patagonian Batholith north segment are exposed. During their evolution most of the granitic rocks were emplaced in metamorphic rocks and other parts were emplaced in Late Jurassic-Berriasan volcanic rocks, Early Cretaceous sedimentary and volcanic rocks,
Publicado em: 2008
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9. Ion microprobe (SHRIMP) dates complex granulite from Santa Catarina, southern Brazil
Complex polymetamorphic granulites have been dated in the Santa Catarina granulite complex of southern Brazil through SHRIMP study of zircon. This complex is dominated by intermediate-acid plutonic rocks and contains small volumes of mafic and ultramafic rocks, and minor quartzite and banded iron formation. Porphyroblasts of orthopyroxene, clinopyroxene and
Anais da Academia Brasileira de Ciências. Publicado em: 2000-12
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10. O complexo mafico-ultramafico de Tijucas do Sul, correlação com o complexo de Pien, PR e considerações metalogeneticas
The study aimed primarily to assess the auriferous deposits potential of gneissic terrains of medium to high metamorphic grade, with lenticular mafic-ultramafic bodies, which outline the suture zone between the Ribeira Belt and the Luís Alves Craton, at the southern border between paraná and Santa catarina. Geological mapping at 1:25.000 scale has been car
Publicado em: 1993
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11. Nanobacteria-like calcite single crystals at the surface of the Tataouine meteorite
Nanobacteria-like objects evidenced at the surface of the orthopyroxenes of the Tataouine meteorite in South Tunisia have been studied by scanning and transmission electron microscopies. A method of micromanipulation has been developed to ensure that exactly the same objects were studied by both methods. We have shown that the nanobacteria-like objects a
National Academy of Sciences.
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12. Nanoscale environments associated with bioweathering of a Mg-Fe-pyroxene
Microorganisms are believed to create microenvironments leading to reaction products not predictable from equilibrium thermodynamics and to unique biomineral morphologies. Unambiguous evidence for such environments is, however, rare in natural samples. We have used scanning transmission x-ray microscopy and spectromicroscopy at the sub-40-nm scale, coupled w
National Academy of Sciences.