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| Natura: | Artículo científico |
| Lingua: | en |
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Academia Brasileira de Ciências
2007
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| Accesso online: | https://www.redalyc.org/articulo.oa?id=32779306 |
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Sommario:
- The Serra da Graciosa A-type Granites and Syenites, southern Brazil. Part 1: Regional setting and geological characterization Silvio R.F. Vlach Guilherme A. R. Gualda Multidisciplinaria (Ciencias Naturales y Exactas) Paraná State Serra da Graciosa Graciosa Province type granites and syenites The Serra da Graciosa region includes important occurrences of granites and syenites of the Graciosa A-type Province(formerly Serra do Mar Suite), southern Brazil. Using fieldwork, petrography, and remote sensing imagery, we characterizethe geology of the plutons in the region. Five individual plutons were recognized. Two correspond to thepreviously defined Marumbi and Anhangava Plutons. We divide the former Graciosa Pluton into three new plutons:Capivari, Órgãos, and Farinha Seca. The plutons are elliptical with northeast-southwest orientation. Two petrographicassociations can be recognized: an alkaline association that includes peralkaline and metaluminous hypersolvus alkalifeldspargranites and syenites (Anhangava, Farinha Seca, Órgãos), and an aluminous association composed of metaluminousand weakly peraluminous subsolvus granites (Capivari, Órgãos, Anhangava, Marumbi). Occurrences ofeach association are limited to one individual pluton or to portions of a pluton, and the age relationships are not wellestablished. Monzodioritic rocks are found marginal to the Órgãos and Farinha Seca Plutons, and interaction with silicicmagmas locally produced hybrid quartz syenites (Farinha Seca Pluton). Geothermobarometry indicates emplacementat shallow crustal levels (P = 2 ± 0.6 kbar), and crystallization temperatures within the interval 900700◦C for thegranitic and syenitic rocks, and 1000750◦C for the monzodioritic rocks. 2007 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32779306 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.79