Paleoproterozoic
Mostrando 1-12 de 51 artigos, teses e dissertações.
-
1. Lithogeochemical and Nd-Sr isotope data of the orthogranulites of the Juiz de Fora complex, SE-Brazil: insights from a hidden Rhyacian Orogen within the Ribeira belt
Abstract New petrography, geochemistry and Sm-Nd and Sr data from the orthogranulites of the Juiz de Fora complex in southern Rio de Janeiro State and compiled information provide insights on the petrogenetic and tectonic evolution. The complex comprises several geochemical groups including mafic orthogranulites (three tholeiitic and one alkaline) and felsic
Braz. J. Geol.. Publicado em: 24/10/2019
-
2. Reconstruction of Precambrian terranes of Northeastern Brazil along Cambrian strike-slip faults: a new model of geodynamic evolution and gold metallogeny in the State of Bahia
Abstract The Precambrian basement of Northeastern Brazil is the product of Rhyacian block convergence. The main deformation and intrusion of crustal granitoids occurred between 2.15 and 1.8 Ga ago. This large area has been subjected to long-lasting and rather uniform stresses during the Cambrian period. Gold provinces in Bahia represent metallogenetic produc
Braz. J. Geol.. Publicado em: 21/10/2019
-
3. U-Pb SHRIMP dating of basement rocks of the Iriri-Xingu domain, Central Amazonian province, Amazonian craton, Brazil
Abstract The Iriri-Xingu domain, located in the central part of the Amazonian craton, consists of extensive occurrences of Paleoproterozoic volcanic rocks and granites with published ages of ca. 1990 to 1840 Ma, which show a strong crustal contribution for their magmas. Exposures of basement rocks are small and rare. Samples from two areas were dated in this
Braz. J. Geol.. Publicado em: 21/10/2019
-
4. 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
-
5. 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
-
6. 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
-
7. The Rio Pardo salient, northern Araçuaí orogen: an example of a complex basin-controlled fold-thrust belt curve
ABSTRACT: The Rio Pardo salient, the large antitaxial curve described by the Araçuaí fold-and-thrust belt along the southeastern edge of the São Francisco craton, is one of the most prominent and one of the least studied features of the Brasiliano Araçuaí-West Congo orogenic system (AWCO). In addition to the Archean/Paleoproterozoic basement, the salien
Braz. J. Geol.. Publicado em: 2018-01
-
8. Analog Models of Flanking Structures and a Natural Example in the Quadrilátero Ferrífero, Minas Gerais
ABSTRACT The aim of this study is to present analog models of flanking structures and to analyze the Fábrica Nova synform, Quadrilátero Ferrífero, Minas Gerais, from a geometric point of view. We set up seven models using a linear viscous silicone and produced flanking structures with a shear velocity of 2 cm h-1. At different initial orientations with re
An. Acad. Bras. Ciênc.. Publicado em: 31/07/2017
-
9. Electron microprobe Th-U-Pb monazite dating and metamorphic evolution of the Acaiaca Granulite Complex, Minas Gerais, Brazil
Abstract The Acaiaca Complex (AC) is located in southeastern Minas Gerais state, and comprises felsic, mafic, ultramafic, and aluminous granulites as well as lower grade gneisses and mylonites. The complex is distributed over an area of ca. 36 km by 6 km, surrounded by amphibolite facies gneisses of the Mantiqueira Complex (MC). The discrepancy in the metamo
Rem: Rev. Esc. Minas. Publicado em: 2016-03
-
10. Petrography and geochronology of the Furquim Quartzite, an eastern extension of the Itacolomi Group (Quadrilátero Ferrífero, Minas Gerais)
Abstract This paper presents the results of a petrographic and geochronological investigation of the Furquim Quartzite (FQ) to establish its stratigraphic correlation to quartzitic units of the Quadrilátero Ferrífero (QF) province. The Quartzite comprises a ca. 20km long and 1-6km wide ridge overlying discordantly the Archean to Paleoproterozoic gneissic b
Rem: Rev. Esc. Minas. Publicado em: 2015-12
-
11. Geocronologia da região de Gondola-Nhamatanda (Centro de Moçambique) / não informado
The region of Gondola-Nhamatanda is located at the border between the provinces of Manica and Sofala, central part of Moçambique. It is geologically inserted in the Bárue complex and the Phanerozoic cover. The Bárue complex is composed of the Macossa and Chimoio supracrustal groups intruded by plutonic rocks of various compositions, whereas the Phanerozoi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/01/2012
-
12. Paleoproterozoic (~1.88Ga) felsic volcanism of the Iricoumé Group in the Pitinga Mining District area, Amazonian Craton, Brazil: insights in ancient volcanic processes from field and petrologic data
O Grupo Iricoumé corresponde ao mais expressivo vulcanismo Paleoproterozóico do Escudo das Guianas, craton Amazônico. As rochas vulcânicas são coexistentes com os granitóides Mapuera, e pertencem ao magmatismo Uatumã. Possuem idades U-Pb em torno 1888 Ma, e assinaturas geoquímicas de magmas tipo-A. As vulcânicas do Iricoumé consistem de traquitos a
Anais da Academia Brasileira de Ciências. Publicado em: 2011-09