Mafic dyke swarms crosscut Archean to Paleoproterozoic country-rocks of the São Francisco craton. The Uauá and Lavras regions include norite (2.73 Ga and 2.66 Ga) and tholeiite dykes (2.62 Ga and 1.97 Ga) respectively. The other swarms are made up of tholeiites: Paraopebas (2.10 Ga), Pará de Minas (1.71 Ga), Curaçá and Chapada Diamantina (1.5 Ga), Diamantina (0.93 Ga) and Salvador-Olivença (0.92 Ga). Geochemical and Sr-Nd isotopic data indicate variable scale of mantle heterogeneity, caused by recurrent metasomatic effects since Archean times, mainly due to the action of slab fluids from recycling of oceanic crusts and overlying sediments on the sub-lithospheric mantle, and by upwelling of OIB-like material. These processes are consistent with the protracted geologic history of the country rocks, given by episodic juvenile accretion and eventual assembly from Archean to ca. 2.0 Ga leading to emplacement of dyke swarms under transpression and/or extensional tectonics. The adopted mixing model, supported by geochemical and isotopic data, permits to evaluate the variation range of slab fluids, OIB and MORB components on the parental mantle composition of the studied dykes.

Mafic dykes from the São Francico Craton, Brazil: ages and inferences regarding the mantle sources / Girardi, V. A. V.; Teixeira, W.; Mazzucchelli, Maurizio; Oliveira, E. P.; Corrêa da Costa, P. C.. - In: COMUNICAÇÕES GEOLÓGICAS. - ISSN 0873-948X. - ELETTRONICO. - 101, Especial 1(2014), pp. 111-113.

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