From TTG-migmatized to crustally-derived granites: Evidence of partial melting and reworking during the Mesoarchean crustal evolution in the southeastern Carajás Province (Amazonian Craton, Brazil)

The transition from Archean tonalite-trondhjemite-granodiorite (TTG) suites to K-rich granitoids represents a key stage in the chemical maturation of the continental crust, yet the timing, sources, and processes governing this evolution remain debated. Understanding this transition is essential to evaluate how early crustal growth, reworking, and stabilization operated under Mesoarchean tectono-metamorphic regimes. The Sapucaia Subdomain of the Carajás Province (2.99-2.86 Ga) constitutes an exceptional crustal archive that preserves multiple pulses of TTG production, high-grade metamorphism, and granite generation, providing a natural laboratory to investigate these processes. Here, we integrate field and structural observations, petrography, whole-rock geochemistry, geochemical modeling, and whole-rock Sm-Nd and zircon Lu-Hf isotopes from TTGs, migmatitic gneisses, and K-rich granites to reconstruct the petrogenetic evolution of this crust. Our results indicate: (1) an initial phase of TTG magmatism at ca. 2.99 Ga; (2) formation of the Caracol Complex gneiss-migmatite between 2.95-2.93 Ga; (3) a renewed TTG pulse at ca. 2.87 Ga (Água Fria trondhjemite); and (4) emplacement of the Xinguara granite at ca. 2.86 Ga, contemporaneous with regional peak metamorphism (2.87-2.84 Ga). TTGs and gneisses exhibit high SiO₂ and Na₂O, low MgO, variable Sr-Y-Yb, strong REE fractionation ((La/Yb)_N = 15.5-165.2), negative Eu anomalies, and mixed isotopic signatures (ε_Hf(t) = -3.4 to +5.8; ε_Nd(t) = -3.4 to +5.8; T_DM = 3.21-2.89 Ga), reflecting interactions between depleted and evolved crustal sources. In contrast, the Xinguara granite shows higher SiO₂ and K₂O, lower Na₂O-CaO, and stronger Eu depletion, consistent with extensive crustal reworking. Geochemical modeling indicates that TTGs originated by 5%-15% partial melting of hydrous metabasalts leaving garnet-amphibolite residues in an arc-related setting, whereas the Xinguara granite derived from 40% to 65% partial melting of pre-existing felsic crust. Migmatites preserve multi-stage anatexis and magma transfer along reactivated shear zones. Collectively, these data demonstrate progressive geochemical differentiation from sodic TTGs to potassic granitoids driven by partial melting, crustal reworking, and intracrustal differentiation, highlighting the Sapucaia Subdomain as a key record of Mesoarchean crustal evolution and stabilization in the Carajás Province.