| Registro completo |
| Provedor de dados: |
Anais da ABC (AABC)
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| País: |
Brazil
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| Título: |
The 1590-1520 Ma Cachoeirinha magmatic arc and its tectonic implications for the Mesoproterozoic SW Amazonian craton crustal evolution
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| Autores: |
Ruiz,Amarildo S.
Geraldes,Mauro C.
Matos,João B.
Teixeira,Wilson
Van Schumus,William R.
Schmitt,Renata S.
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| Data: |
2004-12-01
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| Ano: |
2004
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| Palavras-chave: |
Amazonian craton
U-Pb and Sm-Nd geochronology
Mesoproterozoic
Juvenile magmatism
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| Resumo: |
Isotopic and chemical data of rocks from the Cachoeirinha suite provide new insights on the Proterozoic evolution of the Rio Negro/Juruena Province in SW Amazonian craton. Six U-Pb and Sm-Nd analyses in granitoid rocks of the Cachoeirinha suite yielded ages of 1587-1522 Ma and T DM model ages of 1.88-1.75 Ga (EpsilonNd values of -0.8 to +1.0). In addition, three post-tectonic plutonic rocks yielded U-Pb ages from 1485-1389 Ma (T DM of 1.77-1.74 Ga and EpsilonNd values from -1.3 to +1.7). Variations in major and trace elements of the Cachoeirinha suite rocks indicate fractional crystallization process and magmatic arc geologic setting. These results suggest the following interpretations: (1) The interval of 1590-1520 Ma represents an important magmatic activity in SW Amazonian craton. (2) T DM and arc-related chemical affinity supportthe hypothesis that the rocks are genetically associated with an east-dipping subduction zone under the older (1.79-1.74 Ga) continental margin. (3) The 1590-1520 Ma age of intrusive rocks adjacent to an older crust represents similar geological framework along the southern margin of Baltica, corroborating the hypothesis of tectonic relationship at that time.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652004000400013
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| Editor: |
Academia Brasileira de Ciências
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| Relação: |
10.1590/S0001-37652004000400013
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| Formato: |
text/html
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| Fonte: |
Anais da Academia Brasileira de Ciências v.76 n.4 2004
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| Direitos: |
info:eu-repo/semantics/openAccess
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