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Geologia e petrografia do Grupo Alto Jauru na região da Fazenda Retiro Novo, SW do Cráton Amazônico: evidências de um prisma acrescionário estateriano Translated title: Geology and petrography of Jauru Group, at region of Retiro Novo Farm, SW of Amazonian Craton: a Statherian accretionary prism evidence

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      Abstract

      RESUMO: O Grupo Alto Jauru, localizado no sudoeste do Cráton Amazônico, região da fazenda Retiro Novo, é constituído por biotita-muscovita-quartzo xistos, clorita-biotita-muscovita xistos, granada-cordierita-biotita xisto e estaurolita-andalusita-biotita xisto, associados a granada-sillimanita-biotita gnaisse, biotita gnaisse, anfibolitos e muscovita granito. O grupo apresenta evidências de representar prisma acrescionário dominado por sedimentos. A petrografia e as relações estruturais indicam que foi afetado por dois eventos deformacionais, Dn e Dn+1, com as foliações associadas Sn (xistosidade e bandamento gnáissico) e Sn+1 (clivagem de crenulação) e por três eventos metamórficos (M1, M2 e M3): o primeiro é contemporâneo à Sn de fácies xisto verde inferior; o segundo é associado à fase Sn+1 de fácies xisto verde a anfibolito; o terceiro evento é térmico de fácies anfibolito, resultado da intrusão do Tonalito Cabaçal. A determinação geocronológica obtida pelo método U-Pb (SHRIMP) em zircão forneceu idade de 1819 ± 6,7 Ma para a cristalização do protólito ígneo do biotita gnaisse. Do ponto de vista geotectônico, o Grupo Alto Jauru corresponde a prisma acrescionário formado no Estateriano.

      Translated abstract

      ABSTRACT: The Alto Jauru Group, located in southwestern Amazonian Craton, region of Retiro Novo Farm, comprises biotite-muscovite-quartz schists, chlorite-biotite-muscovite schists, garnet-cordierite-biotite schist and staurolite-andalusite-biotite schist, associated with garnet-sillimanite-biotite gneiss, biotite gneiss, amphibolite and muscovite granite. The group shows evidence of being an accretionary prism dominated by sediments. Petrography and structural relationships indicate that it was affected by two deformational events, Dn and Dn+1, associated with Sn foliation (schistosity and gneissic banding) and Sn+1 (crenulation cleavage), and three metamorphic events (M1, M2 and M3): the first is contemporary with Sn in lower greenschist facies; M2 is associated with the second phase of Sn+1 under greenschist to amphibolite facies; the third thermal event of amphibolite facies resulted from intrusion of the Cabaçal tonalite. Determination obtained by U-Pb (SHRIMP) on zircon provided the age of 1819 ± 6.7 Ma for the crystallization biotite gneiss igneous protolith. From the tectonic point of view, the Alto Jauru Group corresponds to an accretionary prism formed in the Statherian.

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      Most cited references 28

      • Record: found
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      Symbols for rock-forming minerals

       R. Kretz,  R. KRETZ,  P. Kretz (1983)
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        • Record: found
        • Abstract: not found
        • Article: not found

        User’s Manual for Isoplot/Ex, Version 3.0, A geochronological toolkit for Microsoft Excel

          Bookmark
          • Record: found
          • Abstract: not found
          • Article: not found

          Geochronological provinces of the Amazonian Craton

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            Author and article information

            Affiliations
            [1 ] Universidade Federal de Mato Grosso Brazil
            [2 ] Universidade Federal de Mato Grosso Brazil
            [3 ] Universidade de São Paulo Brazil
            Contributors
            Role: ND
            Role: ND
            Role: ND
            Role: ND
            Journal
            bjgeo
            Brazilian Journal of Geology
            Braz. J. Geol.
            Sociedade Brasileira de Geologia
            2317-4692
            March 2016
            : 46
            : 1
            : 129-146
            S2317-48892016000100129
            10.1590/2317-4889201600030309

            This work is licensed under a Creative Commons Attribution 4.0 International License.

            Product
            Product Information: SciELO Brazil
            Categories
            GEOLOGY
            GEOSCIENCES, MULTIDISCIPLINARY

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