Mesoproterozoic
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Mapeamento do potencial mineral para niquel e ouro no Cinturão Metassedimentar Nova Brasilandia - Rondonia por meio de logica nebulosa (fuzzi) e redes neurais artificiais / Mineral potential mapping for nickel and gold in Nova Brasilandia Metassedimentar Belt - Rondonia trough fuzzy logic and artificial neuraL networks
Analysis and integration of spatial data from different natures, particularly on Geographic Information Systems (GIS), is a well known technique in mineral prospection. The available tools and other ones recently developed can help prospection campaigns where there is not enough geologic and metalogenetic knowledge, as the Nova Brasilândia Metassedimentar B
Publicado em: 2008
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14. The occurrence of microdiamonds in Mesoproterozoic Chapada Diamantina intrusive rocks: Bahia / Brazil
A origem dos diamantes da Serra do Espinhaço na região de Diamantina, Minas Gerais e na Chapada Diamantina, na região de Lençóis, Bahia, permanece incerta apesar das inúmeras pesquisas desenvolvidas, ao longo das últimas décadas. A ausência de minerais satélites típicos em ambos os distritos, torna incerta a possibilidade de fonte kimberlítica pa
Anais da Academia Brasileira de Ciências. Publicado em: 2007-06
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15. "Estudo geológico-geocronológico dos terrenos granito-gnáissicos e sequências metavulcanossedimentares da Região do Betara (PR)" / "Geologic-geochronologic study from the granite-gnaissic terranes and metavolcanossedimentary sequences from Betara Region (PR)"
The Betara region was located at nothwest of the Curitiba City between the Campo Largo and Rio Branco do Sul municipal districts. This region includes granite-gnaissic rocks, proto to milonitics (Betara Nucleous) and metavolcanossedimentary sequences with low to intermediate metamorphic grade (Betara Formation). These terrains occur at the southern portion o
Publicado em: 2006
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16. The 1590-1520 Ma Cachoeirinha magmatic arc and its tectonic implications for the Mesoproterozoic SW Amazonian craton crustal evolution
Estudos isotópicos e químicos foram realizados em rochas da Suíte Cachoeirinha, SW do craton Amazônico. Idades U-Pb e Sm-Nd em rochas granitóides desta suíte forneceram idades de cristalização entre 1587-1522 Ma e idades modelo T DM entre 1,88-1,75 Ga (épsilonNd entre -0,8 a +1,0). Em adição, rochas intrusivas apresentam idades U-Pb entre 1485-138
Anais da Academia Brasileira de Ciências. Publicado em: 2004-12
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17. ContribuiÃÃo Ãs tÃcnicas de locaÃÃo de poÃos em terrenos de rochas cristalinas no semi-Ãrido brasileiro
Geological and geophysical studies were accomplished in the areas of Carnaubeira da Penha and Alagoinha in the semi-arid region of Pernambuco where Neo and Mesoproterozoic crystalline rocks occur. The study aimed at a better understanding of the variables upon which well yields are dependent in hard rock territories, in order to improve well site selection t
Publicado em: 2004
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18. Contribution to the tecnicas of location of wells in lands of crystalline rocks in the half-barren Brazilian / ContribuiÃÃo Ãs tecnicas de locaÃÃo de poÃos em terrenos de rochas cristalinas no semi-Ãrido brasileiro
Geological and geophysical studies were accomplished in the areas of Carnaubeira da Penha and Alagoinha in the semi-arid region of Pernambuco where Neo and Mesoproterozoic crystalline rocks occur. The study aimed at a better understanding of the variables upon which well yields are dependent in hard rock territories, in order to improve well site selection t
Publicado em: 2004
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19. Geologia, Geocronologia, Geoquímica e Petrogênese das Rochas Ígneas Cretácicas da Província Magmática do Cabo e suas Relações com as Unidades Sedimentares da Bacia de Pernambuco (NE do Brasil)
The area studied forms a thin NNE-directed belt situated south of Recife town (Pernambuco state), northeastern Brazil. Geologically, it comprises the Pernambuco Basin (PB), which is limited by the Pernambuco Lineament to the north, the Maragogi high to the south and the Pernambuco Alagoas massif to the west, all of them with Precambrian age. This thesis repo
Publicado em: 2003
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20. Evolução geologica das rochas maficas e ultramaficas no Greenstone Belt Barbacena, região de Nazareno, MG
The study area is located at the southem border of the São Francisco Craton and shows plutonic, vo1canic and sedimentary rocks, of Archean to Mesoproterozoic age, reworked by later thermo-tectonic events. Two different groups of mafic and ultramafic rocks occur in this region. The first is a komatiite-tholeiite sequence belonging to the Barbacena Greenstone
Publicado em: 2002
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21. Stromatolites in the mesoproterozoic Itaiacoca Group (se Brazil): paleoenvironmental inferences and comparisons with other similar forms
Anais da Academia Brasileira de Ciências. Publicado em: 2000-12
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22. Analysis of the stromatolites from the Itaiacoca Group (Proterozoic) from south Itapeva, State of São Paulo, Brazil / Análise dos Estromatólitos do Grupo Itaiacoca (Proterozóico), ao Sul de Itapeva, SP
Stromatolites were studied at nine localities south of Itapeva, São Paulo, Brazil, generally in light-gray metadolostones and secondarily in dark-gray metalimestones of the Itaiacoca Group, a Mesoproterozoic volcanosedimentary unit of the Ribeira Belt. Five columnar forms were distinguished, the most common consisting of unbranched, coniform columns, with c
Publicado em: 1999
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23. Estudo do potencial mineral do deposito uranifero de Lagoa Real, BA, com base em dados geologicos, aerogeofisicos e de sensoriamento remoto
Integrated analysis of available geological, geophysical and remote sensing data for the Lagoa Real District yielded a large amount of additional data regarding regional geology and ore controI. This district is Brazil s second largest uranium reserve, associated with albitite lenses enc1osed in Mesoproterozoic granitic rocks within the Paramirim block, at t
Publicado em: 1999
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24. Proterozoic and early Cambrian protists: evidence for accelerating evolutionary tempo.
In rocks of late Paleoproterozoic and Mesoproterozoic age (ca. 1700-1000 million years ago), probable eukaryotic microfossils are widespread and well preserved, but assemblage and global diversities are low and turnover is slow. Near the Mesoproterozoic-Neoproterozoic boundary (1000 million years ago), red, green, and chromophytic algae diversified; molecula