The Palito gold deposit comprises an Au-Cu bearing quartz vein system, hosted in Palito and Rio Novo Paleoproterozoic granites and located in Jamanxim river region, eastern end of the Tapajos gold province, southwestern of Para state. The Palito granite crosscuts the Rio Novo granite and both cut the Fofoquinha Granodiorite. Previous Pb-Pb geochronological data provide the ages of Fofoquinha granodiorite (1946 ± 57Ma), Rio Novo granite (1881 ± 4Ma), gabbroic unit (1872 ± 3 Ma) e also the ore age (179318Ma). However, the age of Palito granite, main aim of this work and essential to model the genesis of Palito deposit, would stay unknown. The Palito and Rio Novo granites are composed of alkali feldspar, plagioclase, quartz, biotite, hornblende and sphene, and also apatite, zircon, rutile, pyrite and sphalerite as accessory minerals. The two granites were characterized as oxidized calc-alkaline monzogranite, typical of magmatic arc. The Palito ore consists of pyrite, chalcopyrite, sphalerite, bismutinite, and also pyrrhotite, galena and gold, being quartz, sericite, chlorite and carbonate the main gangue minerals. The mineralized veins are controlled by a brittle-ductile sinistral stike-slip shear zone of NW-SE main direction which belongs to a regional structure so called Tocantinzinho lineament. The isotopic analyzes to determine the age of the Palito granite were performed at the Laboratory of Isotope Geology (Pará-Iso) of the Geosciences Institute of UFPA, using the evaporation of Pb methodology in crystals of zircon. The geochronological results obtained have showed an average age of 1883 ± 11Ma for the crystallization of Palito granite which overlays the previously obtained age for the Rio Novo granite. The ages of Palito and Rio Novo granites are consistent to late tectonic orogenic granites of the Parauari Orosirian event. Since the Palito deposit is controlled by a shear zone, the age of the shear should be similar to the age of the mineralization event which is younger than the age of the host rocks and also than the age of the younger mineralizing event recognized in the Tapajos Province, coeval to Parauari-Maloquinha granitogenesis. Such a situation does not support a genetic relationship between the Palito gold deposit and the host granites and favors the orogenic model for the genesis of the Palito deposit.
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