The metavolcanosedimentary sequences from the Serra do Navio, included in the Vila Nova group, and associated granitoids are located in the Central region of the State of Amapá, at the limit between two main geotectonic domains of the Maroni-Itacaiunas Province, Southeastern part of the Guyana Shield (i.e. Archean Amapá Block at south and Paleoproterozoic juvenile domain at north). The Amapá block consists of an extensive Archean continental landmass composed by granulitic and gneissic complexes, orthogneisses and migmatites. The main period of crustal accretion took place at the end of Paleoarchean and along Mesoarchean while reworking processes are dominant during Neoarchean. Two major episodes of magmatism were identified at 2.85-2.79 Ga and 2.66-2.60 Ga, respectively. During the Transamazonian orogenic event ((2.26-1.95 Ga), the Amapá Block underwent granite intrusions, formation of metavolcanosedimentary and high –grade metamorphism episodes. In the Serra do Navio area, the supracrustal sequences of the Vila Nova group occur as NW-SE elongated belts. These sequences are composed by a basal orthoanphibolites and metamafic rocks overlain by quartzschists with lenses of calk-silicated rocks, biotite-schists, graphitic-schists including lenses of calcic and manganesiferous marble. All the units are metamorphosed under greenschist to amphibolite facies. Several bodies of foliated monzogranites and foliated and isotropic granodiorites crosscut the supracrustal sequences. Foliated mongranites and granodiorites exhibit geochemical signature of sub-alkaline, slightly peraluminous granites similar with A type granites (A2 type). Isotropic granodiorites display characteristics of calk-alkaline, peraluminous, fractionated I type granites. Trace and Rare earth elements geochemical data indicated that the amphibolites consists of T- MORB like andesitic basalts and suggest that they formed in extensional context, probably in a retro-arc basin. Sm-Nd isotopic results on five samples of amphibolites furnished _Nd(2.23 Ga) values between +0.91 and +3.55, indicating a major mantle derivation with slight contribution of crustal magmas in the source or crustal contamination during the genesis of these rocks. Schist samples from the same sequences displayed slightly positive to negative _Nd values (-4.98 < _Nd(2.23Ga) < +0.57) pointing to the assimilation of crustal material from the Archean basement or contamination by metamorphic fluids. The Nd isotopic values of _Nd (2.23 Ga) between -4.88 and +3.15, with corresponding TDM Nd model ages from 2.24 Ga up to 2.84 Ga obtained on seven samples from granitoids indicated an important contribution of an Archean crustal component in the source of these rocks, also registered by Archean inherited up to 2.71 Ga, as well as Paleoproterozoic juvenile sources for some of the studied granitoids. Pb-Pb ages on zircon from three samples of monzogranites and granodiorites between 2.23 – 2.25 Ga suggest that they formed during an Eorhyacian episode of magmatism. Such ages also suggest that the Vila Nova supracrustal sequences, in which the granitoids are intrusive, also formed during an early Transamazonian episode and are contemporaneous with the Ipitinga group, at the southern border of the Amapá block and with the “l´ile de Cayenne” mafic rocks in French Guyana. Therefore, the Vila Nova group at the Serra do Navio does not belong to the Mesorhyacian greenstones belt from the Southeastern Guyana shield and constitutes a further evidence of the Eorhyacian stage of oceanic crust formation which began the Transamazonian evolution of the Maroni-Itacaiunas Province.
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