The basement rocks of the Araguaia Belt (AB) consists predominantly of Archean and Paleoproterozoic rocks. The former predominates in the northern segment while the Paleoproterozoic rocks prevail in the southern portion. To the north, the basement rocks crop out in the core of dome-like structures, and are represented mainly by TTG affinity Archean orthognaisses (Colmeia Complex), with minor Paleoproterozoic granitic gneisses (Cantão Gneiss). To the south the ortho- and paragnaisses of the Rio dos Mangues Complex (RMC) and the Serrote Granite (GS) are the main Paleoproterozoic rock units. Neoarchean (Rio do Coco Group) and Mesoproterozoic (Monte Santo Suite) rock units occur locally. Single zircon Pb-evaporation dating defined ages around 2.86 Ga for the Colmeia Complex (CC) orthognaisses. For CRM gneisses these ages were in the range of 2.05-2.08 Ga. In turn, the age of 1.86 Ga was obtained for GS that intrudes the CRM gneisses. Recent U-Pb zircon dating by LA-MC-ICPMS revealed different ages for the orthognaisses of Lontra (2905 ± 5,1 Ma) and Cocalandia (2869 ± 11 Ma) dome-like structures. Aware of the analytical limitations of the Pb-evaporation technique, this study resumed the dating of the CA basement rocks using the U-Pb zircon method by LA-MC-ICPMS. This investigation was complemented by the use of the Lu-Hf zircon system to understand the evolution of this crustal segment. The ages 2930 ± 15 Ma, 2898 ± 11 Ma and 2882 ± 9 Ma were determined for the orthognaisses of the Xambioá, Grota Rica and Colméia dome-like structures, respectively. These ages, together with those published for the orthognaisses of Lontra and Cocalândia dome-like structures, indicate that the igneous protoliths of the orthognaisses of CC were generated by distinct magmatic events spanning 60 Ma. The Hf-TDMC ages of the zircon crystals of these rocks indicate an origin from a juvenile crust formed in the Mesoarchean, with the largest contribution of older crustal material to the Grota Rica and Colmeia gneiss protoliths. An age of 2059.7 ± 6.4 Ma was obtained for an orthogneiss from the RMC. For a porphyritic metasyenogranite (GS) the age of 1868 ± 16 Ma was defined. Both ages corroborate the previously published Pb-evaporation ages. In both rocks, the Hf-TDMC ages and ƐHf (t) values occur at very similar intervals, indicating that they were generated from the same neomesoarchean source. Alternatively, the RMC orthognaisses could result from mixing between mesoarchean rocks and Paleoproterozoic juvenile crust. In this case, the GS could result from partial melt of the RMC gneisses. Two gneisses sampled as belonging to the RMC showed Neoproterozoic ages. The first one is a tonalitic orthogneiss whose protolith crystallized at 599 ± 15 Ma. It has inherited zircons ranging in age from 677 to 2990 Ma. The Hf-TDMC model ages of the crystals that defined the age of 599 Ma were between 1.43 and 1.97 Ga, with ƐHf (599 Ma) ranging from -10.90 to -0.88. These values suggest that reworking older crustal rocks, possibly with smaller contributions of Neoproterozoic mantle material, generated the tonalitic magma. The other rock is a sillimanite-rich paragneiss with detrital zircon ages between 594 and 2336 Ma.Therefore, the maximum age of the sedimentary protholite is less than 590 Ma. The Hf-TDM C model age values for these crystals indicate that the source rocks were generated predominantly by reworking older material. The metamorphic event that formed these younger gneisses is probably associated with the collision of the Goiás Magmatic Arc with the southern segment of the CA basement, within the context of formation of the Gondwana Supercontinent in the Neoproterozoic.
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