The Borborema Province extends for approximately 450,000 km2 in the northeastern portion of Brazil and represents a complex geotectonic unit, characterized by a collage of crustal blocks with different ages, origins and evolution. Comprises domains such as the Granjeiro Complex, whose highly deformed paleoproterozoic gneissic basement locally includes Archaean nuclei that alternate with remnants of supoprostal and paleoproterozoic supracrustal rocks, all intruded by numerous granite bodies of Brasilian age (ca. 0.60-0.50 Ga) placed along shear zones. In the region of Granjeiro-Várzea Alegre (CE), north of the Patos Lineament, a variety of rocks forms an imbricated system, Duplex type, with units of different ages. Geochronological studies of U-Pb and Lu-Hf in zircon by laser ablation mass spectrometry (LA-ICP-MS) were performed in 5 samples and provided crystallization ages for a Hornblende-Biotite tonalitic gneiss at 2549 ± 16 Ma (OG-07) and at 2532 ± 10 Ma (OG-03) of the Granjeiro Complex; a Hornblende tonalitic orthogneiss at 2354 ± 15 Ma (OG-05) of the Arrojado Complex; a Hornblende-Biotite monzogranitic orthogneiss at 2224 ± 12 Ma (OG-09) from the Várzea Alegre Suite and for a Biotita Monzogranite at 570 ± 6 Ma (G-02) from the Pereiro magmatic arc. The isotopic signatures of Hf (zircon) and Nd (whole-rock) provided model ages (Hf-TDM; Nd-TDM) for these rocks, respectively: OG-07 (2.75 to 2.93 Ga, 2.54 Ga), OG-03 (2.70 to 2.96 Ga and 2.75 Ga), OG-05 (2.92 to 3.06 Ga, 2.96 Ga) and OG-09 (2.84 to 3.01 Ga; 2.90 Ga ) and for the granitoid G-02 (2.94 to 3.27 Ga, 2.10 Ga). The parameters ƐHf (t) and ƐNd (t) for these rocks, respectively, were OG-07 (ƐHf: +1.41 to +4.33; ƐNd: +2.81) and OG-03 (ƐHf: +3.16 to +4.79, ƐNd: -0.37) suggesting contribution of juvenile sources in the protoliths of these rocks; OG-05 (ƐHf: -0.28 to -4.11, ƐNd: -0.23) and OG-09 (ƐHf: -3.86 to -1.15; ƐNd: -5.31) suggesting reworking of Archaean crustal source. The values of the granitoid G-02 (ƐHf: -23.70 to -29.15; ƐNd: -20.10) are strongly negative, suggesting that the magma that originated these rocks was product of reworking of paleoproterozoic (Rhyacian-Siderian) and mesoarquean sources. The integrated isotopic results (U-Pb and Hf-Nd) allowed the identification of at least 4 tectono-magmatic events in the region of Granjeiro-Várzea Alegre. The age range (ca. 2.54-2.53 Ga) and juvenile signatures mark a moment of Archaean crustal growth related to the formation of the Granjeiro Complex. It was also recognized a formation of paleoproterozoic crust (ca. 2.35 Ga), correlated to the Arrojado Complex, whose negative values of ƐHf and ƐNd suggest sources derived from reworked Archaean crust. The rocks of the Granjeiro Complex would have been deformed and assimilated in an event of crustal growth ca. 2.22 Ga, that generated the rocks of the Várzea Alegre Suite. The age of 570 Ma records the last magmatic episode and marks the development of the Borborema Province shear zones that affected and deformed the archaean and paleoproterozoic rocks of this domain.
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