A section of the Brasiliano Mobile Belt (650-450 Ma) was investigated in Espirito Santo from structural, petrological and geochemical points of view. The Archean granulitic rocks of the Juiz de Fora Complex show less recrystallization after formation of large scale folds than the Alegre Complexo Both complexes are separated by a steeply Edipping ductile shear zones (Guacui Lineament). In the Alegre, Complex anatexis and granitisation ocurred in a relatively early stage of deformation. Later gregarious basic to intermediate zoned diapirs intruded all units. Four of these diapirs have been mapped (scale of 1:50.000) and sampled. Petrological and geochemical data indicate a mantle origin magma mixing, differentiation and host rock aasimilation. This group of zoned plutons shows a, complex internal structure with large compositional variation, grading from olivine OPX-hornblende-gabbros, through OPX-CPX-biotite diorites, CPX-biotite monzodiorites up to biotites syenomonzonites (Jacutinga-Torre Complex and to a smaller extent, Venda Nova Complex). OPX-hornblende-biotite monzogabbros and monzodiorites, hornblende-biotite granodiorites and allanite-sphene-biotite granites occur in Santa Angelica and Castelo Complexes. A contemporaneous megmatism of melanocratic and leucocratic rocks produced a complicated pattern of mixed rocks. The presence of mantled feldspars, the different Rb/Sr rations for different lithologies, inherited zircons together with some other petrographic and geochemical characteristics are indicative of fusion of the mantle material which was mixed with different amounts of crustal melting, thus originating hybrid plutons of post-collision types. In this paper, it is analysed the problem of rock contamination, differentiation and production of granitic magma. The showed data was interpreted by a model which involves a large scale thrusting of the Juiz de Fora Complex towards the west over the Alegre Complexo. This also suggests a continent-continent collision which was followed by domic upwarping that exposed the structurally deeper Alegre unit.