Litogeoquímica, geocronologia (U-Pb) e geoquímcia isotópica (Sr-Nd) dos granitoides do Domínio Cambuci (Faixa Ribeira) na região limítrofe dos Estados do Rio de Janeiro e Espírito Santo

Abstract

The granitoids of Cambuci Domain, situated between Rio de Janeiro and Espírito Santo states, were divided into four main groups: (1) Serra Bolivia Complex (CSB) - Heterogeneous Orthogranulites and Orthogneisses; Grey Fine grained Orthogneiss; and charnockites of Monte Verde Region (2) leucogranites / leucocharnockites gness of the São João do Paraíso Suite (SSJP) (3) Grey Foliated Granite (4) Isotropic Leucogranite. The CSB is characterized by type I calc character of magmatism, generate in volcanic arc environment (Monte Verde Suite) and crustal reworking (Leucocratic ortogranulites). The Fine grained Greenish, is considered in this research as the embasement rock for the Oriental Terrain, crystallized during the Paleoproterozoic - Riacian (2184.3 ± 21 Ma) and recrystallized during in the metamorphic event in the Neoproterozoic - Edicarian (607.2 ± 1.5 Ma), whose TDM age is 2936 Ma. The Medium grained Leucocratic Ortogranulite was crystallized in the Neoproterozoic - Edicarian (between 592 and 609 Ma) and its TDM age is ca. 2100 Ma, which features heritage record in the Paleoproterozoic. The Monte Verde Suite is characterized by a magmatism calcialcalin and the Córrego Fortaleza Suite, magmatism calc-alkaline high K, both show magmatic arc signature. Records two magmatic pulses in a sample (JP-RM-08A) in the Neoproterozoic - Edicaran: the first one in 592 ± 2 Ma, and TDM age 1797 Ma, and the second one in 571.2 ± 1.8 Ma (injecting a charnockitoids). For all CSB rocks, protomylonítics, Mylonitic and locally ultramilonítics features were portrayed. Geochemical data show these SSJP granitoids are the calc-alkaline series of high-K, crystallyzed in Neoproterozoic (ranging from 610.3 ± 4.7 Ma to 592.2 ± 1.3 Ma). TDM ages show outliers in two samples: 1918 Ma and 2415 Ma, suggesting that have been generated from different sources. The Gray Foliated Granite belongs to the shoshonitic series, type I and metaluminous and are intraplate granites. However, could have been formed into arc cordilheirano, with crustal contamination of other sources. This fact would be confirmed by the TDM ages calculated ≈ 1429 - 1446 Ma. The Isotropic Leucogranite occurs in the form of dykes, NW direction, has massive texture and is inequigranular. Geochemical data show these granitoids are metaluminous the type I shoshonitic series. They are intraplate granites. The Isotropic Leucogranite represents the post-collisional magmatism which took place between 80 and 90 Ma years after the collisional event in central sector of Ribeira Belt. It is crystallized in the Cambrian (512.3 ± 3.3 Ma e 508.6 ± 2.2 Ma) and TDM ages, ca. 1900 Ma