The Juiz de Fora Complex in the region of Três Rios (RJ): lithogeochemistry, geochronology e isotopic geochemistry of Nd / O complexo Juiz de Fora na região de Três Rios (RJ): litogeoquímica, geocronologia U-Pb (LA-ICPMS) e geoquímica isotópica de Nd

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The Juiz de Fora Complex (JFC) in the region of Três Rios (Rio de Janeiro) is appointed by an ample variety composicional, having from granites, tonalite to rocks of composition basic. Through the lithogeochemistry it was possible to subdivide this unity in 4 associations: (i) calc-alkaline of high-K, (ii) calc-alkaline of medium-K, (iii) tholeiitic and (iv) alkaline. By the geochronological analysis(LA-ICPMS, U-Pb) was obtained the age of 2,1Ga for the calc-alkaline group of medium-K, two ages neoproterozoic (615.9 6.4 Ma and 589.1 5 Ma) were dated in an orthogranulite of the toleítico group, what they were interpreted like ages of metamorphism. The model age of Nd (≈ 2,37 Ga) and the data of U-Pb and lithogeochemical mark the hypothesis of the calc-alkaline group of middle-K represents rocks of a youthful magmatic arc. The isotópica together with the lithogeochemistry analysis suggests that the toleítica group of the CJF of the studied region were produced in environment of ocean extensional, being differentiated from a fountain depletada with some contribution of a rich fountain.

ASSUNTO(S)

três rios isotopic geochemistry of nd complexo juiz de fora geologia três rios geocronologia u-pb (la-icpms) lithogeochemistry, geocronology u-pb (la-icpms) geoquímica isotópica de nd juiz de fora complex litogeoquímica

ACESSO AO ARTIGO

Documentos Relacionados