U Pb
Mostrando 13-24 de 326 artigos, teses e dissertações.
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13. Metamorphic modeling and petrochronology of metapelitic rocks from the Luminárias Nappe, southern Brasília belt (SE Brazil)
Abstract The Luminárias Nappe was formed in the agglutination of West Gondwana. A high-pressure metamorphic gradient oblique to the geological contacts is recorded in metapelitic rocks from this Nappe. In the northern portion, the metamorphic peak conditions are at high-pressure lower-amphibolite facies at 580 ± 4°C and ca. 0.9 GPa (Chl + Ky + St + Ms + Q
Braz. J. Geol.. Publicado em: 06/06/2019
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14. Sedimentary and U-Pb detrital zircons provenance of the Paleoproterozoic Piracicaba and Sabará groups, Quadrilátero Ferrífero, Southern São Francisco craton, Brazil
Abstract The Quadrilátero Ferrífero is an important mineral province located in Southern São Francisco craton, SE Brazil. Its prominent feature is the Gandarela syncline that was formed as part of the regional deformation event in the southernmost part of the craton at ca. 2,000 Ma. The syncline exposes several economically important units of Rio das Velh
Braz. J. Geol.. Publicado em: 03/06/2019
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15. The Barreiro suite in the central Ribeira Belt (SE-Brazil): a late Tonian tholeiitic intraplate magmatic event in the distal passive margin of the São Francisco Paleocontinent
Abstract New geochemical, U-Pb, Lu-Hf and Sr-Nd data from the Barreiro Suite metabasites in comparison with enclaves within the distal Andrelândia Group and the orthogranulites of the Juiz de Fora Complex are presented. Geochemical data suggest intraplate setting, with high and low-TiO 2 , TDM Nd ages between 1.80 and 1.41 Ga, negative ΕNd t and ( 87 Sr/ 8
Braz. J. Geol.. Publicado em: 20/05/2019
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16. Petrography and detrital zircon U-Pb geochronology of sedimentary rocks of the Campo Alegre Basin, Southern Brazil: implications for Gondwana assembly
Abstract The Campo Alegre Basin is a volcano-sedimentary sequence covering an area of about 500 km 2 , located at the northeast portion of Santa Catarina state (Brazil), and formed during the late stages of the Neoproterozoic era. Three main stratigraphic units compose this basin, the lowermost of which is the Bateias Formation, corresponding to the pre-volc
Braz. J. Geol.. Publicado em: 15/04/2019
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17. Stratigraphy and tectonic setting of the Barriga Negra Formation in Uruguay: an update
Abstract The aim of this work is to propose a new stratigraphic scheme of the Barriga Negra Formation, in order to solve the controversies in one of the most discussed units of Uruguay. Here, we introduce a new map (unmodified since 1984) and amend the stratigraphic profile for the Barriga Negra Formation, establishing the correct sequence, order and thickne
Braz. J. Geol.. Publicado em: 08/04/2019
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18. Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil
Abstract The Alto Moxotó Terrane represents the largest exposure of Paleoproterozoic rocks in the central Borborema Province. Several medium- to high-grade metamorphic units are described in the terrane, however geochronological data are still scarce, and the main periods of crust build-up and recycling are poorly known. In this study, we investigate the na
Braz. J. Geol.. Publicado em: 08/04/2019
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19. The Vazante and Canastra groups revisited: Sm-Nd and Sr isotopes - evidence for contribution from Tonian intraplate magmatism during passive margin development along the SW São Francisco margin, Brazil
Abstract Combined Sm-Nd isotope studies and U-Pb ages of detrital zircons have shown significant differences between the provenance patterns of Neoproterozoic metasedimentary successions in the Southern Brasília belt. The Vazante and Canastra groups are passive margin deposits with source areas in the Archean/Paleoproterozoic São Francisco Craton basement
Braz. J. Geol.. Publicado em: 08/04/2019
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20. Fit-for-Purpose ICP-MS Procedure Supporting Brazilian Regulations on Inorganic Constituents in Fresh and Saline Waters
This work aimed the development of an analytical procedure using inductively coupled plasma mass spectrometry (ICP-MS) in four modes of operation for simple and fast determination of Al, Ag, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Na, Ni, Pb, Sb, Se, Tl, Hg, V, U, and Zn in fresh and sea water samples attending simultaneously four Brazilian regula
J. Braz. Chem. Soc.. Publicado em: 2018-07
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21. Clinical trial for uniform multidrug therapy for leprosy patients in Brazil (U-MDT/CT-BR): adverse effects approach
Abstract: BACKGROUND: The Clinical Trial for Uniform Multidrug Therapy for Leprosy Patients in Brazil (U-MDT/CT-BR), designed to evaluate the effectiveness of a six-months regimen, assessed the adverse effects caused by the drugs. OBJECTIVE: Describe adverse effects due to MDT in U-MDT/CT-BR, comparing the uniform regimen (U-MDT) to the current WHO regimen
An. Bras. Dermatol.. Publicado em: 2018-06
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22. New age determinations for the Banhadão and Itapirapuã complexes in the Ribeira Valley, southern Brazil
ABSTRACT: New age determinations by Ar-Ar and U-Pb SHRIMP for the alkaline complexes of Banhadão and Itapirapuã that occur in the Ribeira Valley are in agreement with the previously radiometric K-Ar ages available in literature. Ar-Ar ages on biotite for Banhadão range in the 106-110 Ma interval, and suggest a minimum age of 106 Ma for the complex. Ar-Ar
Braz. J. Geol.. Publicado em: 08/03/2018
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23. Avaliação dos níveis de chumbo e mercúrio em população exposta ambientalmente na Região Centro-oeste do Brasil
O objetivo foi avaliar o nível de exposição ao chumbo e mercúrio em população do Pantanal Mato-grossense, Brasil. Chumbo no sangue (Pb-S) (n = 119) e mercúrio na urina (Hg-U) (n = 109) de moradores da região foram determinados por espectrometria de absorção atômica. A comparação de médias e correlação entre as variáveis utilizaram o teste AN
Cad. Saúde Pública. Publicado em: 01/03/2018
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24. Sedimentary provenance in the southern sector of the São Francisco Basin, SE Brazil
ABSTRACT: We present new Sm-Nd, U-Pb and Hf isotope geochronological data for the siliciclastic rocks in the southern sector of the São Francisco Basin. An abrupt change in the Sm-Nd data is observed from the Carrancas Formation’s oligomitic conglomerates (TDM ages between 2.7 and 3.3 Ga; εNd(550 Ma) values between -25.09 and -17.98), its finer facies, a
Braz. J. Geol.. Publicado em: 2018-01