Evidências de Mingling na Unidade Gentileza, Domínio Canindé, faixa de dobramentos sergipana

• Ano de defesa: 2019
• Autor(a) principal: Almeida, Cássio Brener Andrade
• Orientador(a): Machado, Adriane
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Geociências e Análise de Bacias
• Palavras-chave em Português: Geociências; Petrologia; Geoquímica; Rochas ígneas; Granito; Geocronologia; Mingling; Unidade Gentileza (SE); Granito Boa Esperança; Domínio Canindé (SE); Faixa de dobramentos sergipana; Gentileza Unit (SE); Boa Esperança Granite; Canindé Domain (SE); Sergipano Fold Belt
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/12522

The Sergipano Fold Belt (SFB), characterized by Precambrian fold and thrust belt, is located in the Northeast region of Brazil and is the result of collision between Congo-São Francisco Craton and Pernambuco-Alagoas Massif, during Brasiliano/Pan-African Orogeny. The SFB shows geological complexity evidenced by five lithological and structural domains called Canindé, Poço Redondo-Marancó, Macururé, Vaza Barris e Estância. The Canindé Domain is located in Northern region of SFB and shows an elongated shape, with NW-SE direction, parallel to São Francisco River (SE), with 4-10 km wide, composed by Novo Gosto-Mulungú, Gentileza and Canindé Gabbroic Intrusion units, besides the several granites that intrudes the older domain units. The object of this work was the road cut outcrops, with 1.4 km extension, located along SE-200 highway, north portion of Canindé do São Francisco (SE) city. The objective of this work was identify and characterize the mineralogy, the textural aspects and the mingling features present in the mafic term (amphibolite - Gentileza Unit) and felsic (metamonzogranite/metasyenogranite - Boa Esperança Granite). The work stages covered eight fieldwork, macro and microscopic studies and total whole rock geochemical analysis. The observed mingling features are pillow-like structures, filter-pressing and complex portion with felsic injections. The amphibolite of Gentileza Unit is massive and granular, sometimes foliated with medium to fine equigranular texture. Microscopically, the amphibolite is inequigranular, hipidiomorphic, with Mineralogy composed by hornblende (28-56.7%), biotite (1.2-12.1%), plagioclase (18.3-39.9%), quartz (0.2-6.5%), opaque minerals (0.4-5.4%), titanite (0.8-4.5%), zircon (<1%), apatite (0.3-1.6%), sericite (0-7.9%), chlorite (0-2.3%), epidote (<1%) and carbonate (0-3%). The metamonzogranite (Boa Esperança Granite) is massive, with beige to pink color and medium to fine and it is inequigranular. Microscopically, it has medium to thick granulometry, composed by quartz (36.5-38.5%), K-feldspar (20.4-33.3%), plagioclase (19.3-27.6%), biotite (1.6-3.8%), opaque minerals (1.5-3.2%), titanite (0.3-1.3%), apatite (0.2-0.3%), sericite (5.8-7.1%), epidote (0.2-0.6%) and chlorite (0.2-0.6%). The metasyenogranite (Boa Esperança Granite) shows inequigranular crystals, with medium to fine granulometry, composed by quartz (47%), K-feldspar (34%), plagioclase (5%), biotite (1%), opaque minerals (2%), titanite (1%), apatite (1%), sericite (8%) and epidote (1%). Geochemical data indicate that the protolith of amphibolite corresponds mostly to basaltic andesites and andesites. The trace elements multi-element diagram, the amphibolite presents a LILE and HFSE enrichment pattern in relation to HREE, with Ta, Ti and P negative anomalies and positive of La. The REE patterns for amphibolite show LREE enrichment in relation to HREE. The amphibolite geochemical data are compatible with magmas generated in geotectonic environment of continental intraplate type, possibly represented by a continental rift, while the metamonzogranite/metasyenogranite data indicate a magma generated in volcanic arc environment.