Post-Collisional magmatic evolution of the Castelo Intrusive Complex, Espírito Santo, Brazil: New U-Pb geochronological data and integration of petrographic and geochemistry evidence

The Castelo Intrusive Complex (CIC), located in the southern region of the Espírito Santos state, southeastern Brazil, is a pluton inserted in the context of post-collisional magmatism of the Araçuaí Orogeny, known as Supersuite G5, related to the extensional collapse during the Brasiliano/Pan-African Orogeny. This work integrates field, petrographic, lithogeochemical, and isotopic data, bringing new U-Pb ages for the CIC and a new geological map. The CIC presents a great compositional variety, presenting rocks of monzogranitic, granodioritic, quartz-monzodioritic, and dioritic. The U-Pb data from the granite from the northern edge, yielded an upper intercept age of 504 ± 6 My. The diorite from the massif's core yielded a 514 ± 6 My crystallization age. The granite from the western edge yielded a crystallization age of 529 ± 3 My. The U-Pb ages from the literature suggest two magmatic episodes (529-514My and 510-504 My) for forming the CIC. The lithological variety of the CIC is also expressed in the lithogeochemical data set with a range of SiO2 contents (50.19% to 74.14%) and in the variation observed in the R1-R2 diagram for the classification of plutonic rocks. The principal component analysis for litogeochemical results reinforces the existence of two large groups of rocks, an older group 1 (granites, granodiorites, and tonalities) and a younger group 2 (granodiorites, mozo-diorites, monzonites, diorites, and tonalites). The correlation matrices between the principal components reveal the prominent role of the magma mixing process. The normalized multi-element diagram of chondrite shows that the negative Eu anomaly was more pronounced for group 1 and enrichment in ETRL, with pronounced fractionation. The classification diagrams demonstrate that the rocks of the CIC are ferrous to weakly metaluminous, alkaline-calcic to calc-alkaline, with a positive trend between the silica content and the Na2O+K2O-CaO parameter, and meta- to peraluminous saturated in silica suggesting an alkaline arc environment for its origin.