Geologia da folha guapiara 1:50000 (SG-22-X-B-II-2)
Data
2017-04-13
Autores
Vieira, Otávio Augusto Ruiz Paccola [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A Folha Topográfica de Guapiara 1: 50000 (SG-22-X-B-II-2) situa-se no extremo sul do estado de São Paulo e compreende na porção central da Província Mantiqueira a faixa centro-sul do Cinturão Ribeira. O arcabouço geológico local envolve rochas da sequência metavulcanossedimentar do Supergrupo Açunguí, de idade meso- a neoproterozoicas metamorfizadas e deformadas no Neoproterozoico, associadas a rochas granitoides gerados durante os episódios colisionais ligados ao Ciclo Brasiliano e à formação do Supercontinente Gondwana. Na região, oito unidades litoestratigráficas principais foram mapeadas: metassedimentos da Formação Água Clara e dos grupos Votuverava e Itaiacoca de idade meso- a neoproterozoica, corpos graníticos neoproterozoicos representantes do Granito Três Córregos, corpos graníticos neoproterozoicos a cambrianos do Granito Capão Bonito, rochas sedimentares do Grupo Itararé, intrusivas básicas associadas a Formação Serra Geral e sedimentos recentes Quaternários. O quadro estruturalmetamórfico é determinado dominantemente pelo arranjo tectônico final neoproterozóico, evidenciado nas rochas epimetamórficas por uma evolução estrutural do tipo polifásica. As estruturas primárias S0, devido aos intensos processos de transposição das foliações dúctil e deformação milonítica, apresentamse preservadas de forma escassa em algumas áreas, com predomínio somente do acamamento gradacional reliquiar S0, nas áreas menos deformadas, a um bandamento tectônico nas regiões da zona de cisalhamento. São registradas quatro fases deformacionais e três metamórficas principais: a fase Dn, de baixo a médio ângulo e direção preferencial NE/SW, subparalela ao bandamento composicional S0; a fase Dn+1, de baixo a médio ângulo e direção preferencial NW/SE; a fase Dn+2, de alto ângulo e direção preferencial NE/SW, sendo esta fase a mais penetrativa e a principal e a fase Dn+3, de alto ângulo e direção preferencial NW/SE. Os eventos metamórficos associados são caracterizados pelo metamorfismo M1, o ápice metamórfico, do tipo regional progressivo na fácies xisto-verde alto a anfibolito baixo; M2, do tipo de contato em condições de baixa pressão e baixa a média temperatura, com a formação de hornfels e skarns locais; M3 metamorfismo regional regressivo na fácies xisto-verde baixa.
The Topographic Sheet of Guapiara 1: 50000 (SG-22-X-B-II-2) is located in the southernmost part of the state of São Paulo and comprises the central portion of the Mantiqueira Province, the central-southern belt of the Ribeira Belt. The local geological framework involves rocks from the metavulcanosedimentary sequence of the Açunguí Supergroup, meso to neoproterozoic metamorphosed age and deformed in the neoproterozoic, associated with granitoid rocks generated during the collisional episodes related to the Brasilian Cycle and to the formation of the Gondwana Supercontinent. In the region, eight main lithostratigraphic units were mapped: metasediments of the Água Clara Formation and the Votuverava and Itaiacoca Groups of meso-neoproterozoic age, neoproterozoic granite bodies representing the Três Córregos Granite, granite neoproterozoic bodies of the Capão Bonito Granite, sedimentary rocks of Itararé Group, basic effusives rocks associated with the Serra Geral Formation and recent sediments of the Quaternary. The structuralmetamorphic framework is dominantly determined by the final neoproterozoic tectonic arrangement, evidenced in the epimetamorphic rocks by a structural evolution of the polyphase type. The primary structures S0, due to the intense processes of transposition of ductile foliations and milonite deformation, are sparsely preserved in some areas, with predominance only of the relic gradation bedding of S0, in less deformed areas, to a tectonic banding in the regions of Shear Zone. Four deformational phases and three main metamorphic phases are recorded: the Dn phase, low to medium angle and preferential direction NE / SW, which is subparallel to the compositional bandage S0; The Dn + 1 phase, from low to medium angle and preferential direction NW / SE; The phase Dn + 2, of high angle and preferential direction NE / SW, this being the most penetrative and the main phase and the Dn + 3 phase, of high angle and preferential direction NW / SE. The associated metamorphic events are characterized by the metamorphism M1, the metamorphic apex, of the regional progressive type in the high greenschist to low amphibolite facies; M2, contact type under low pressure conditions and low to medium temperature, with the formation of hornfels and local skarns; M3, regressive regional metamorphism in low greenschist facies.
The Topographic Sheet of Guapiara 1: 50000 (SG-22-X-B-II-2) is located in the southernmost part of the state of São Paulo and comprises the central portion of the Mantiqueira Province, the central-southern belt of the Ribeira Belt. The local geological framework involves rocks from the metavulcanosedimentary sequence of the Açunguí Supergroup, meso to neoproterozoic metamorphosed age and deformed in the neoproterozoic, associated with granitoid rocks generated during the collisional episodes related to the Brasilian Cycle and to the formation of the Gondwana Supercontinent. In the region, eight main lithostratigraphic units were mapped: metasediments of the Água Clara Formation and the Votuverava and Itaiacoca Groups of meso-neoproterozoic age, neoproterozoic granite bodies representing the Três Córregos Granite, granite neoproterozoic bodies of the Capão Bonito Granite, sedimentary rocks of Itararé Group, basic effusives rocks associated with the Serra Geral Formation and recent sediments of the Quaternary. The structuralmetamorphic framework is dominantly determined by the final neoproterozoic tectonic arrangement, evidenced in the epimetamorphic rocks by a structural evolution of the polyphase type. The primary structures S0, due to the intense processes of transposition of ductile foliations and milonite deformation, are sparsely preserved in some areas, with predominance only of the relic gradation bedding of S0, in less deformed areas, to a tectonic banding in the regions of Shear Zone. Four deformational phases and three main metamorphic phases are recorded: the Dn phase, low to medium angle and preferential direction NE / SW, which is subparallel to the compositional bandage S0; The Dn + 1 phase, from low to medium angle and preferential direction NW / SE; The phase Dn + 2, of high angle and preferential direction NE / SW, this being the most penetrative and the main phase and the Dn + 3 phase, of high angle and preferential direction NW / SE. The associated metamorphic events are characterized by the metamorphism M1, the metamorphic apex, of the regional progressive type in the high greenschist to low amphibolite facies; M2, contact type under low pressure conditions and low to medium temperature, with the formation of hornfels and local skarns; M3, regressive regional metamorphism in low greenschist facies.
Descrição
Palavras-chave
Guapiara, Mapeamento, Estrutural, Metamorfismo