2022-09-302022-09-302022-09-16SILVA, Luciano Ribeiro da. Petrogênese e história tectônica dos granitóides mesoarqueanos de Ourilândia (PA) – Província Carajás. Orientador: Davis Carvalho de Oliveira. 2022. 302 f. Tese (Doutorado em Geoquímica e Petrologia) - Programa de Pós-Graduação em Geologia e Geoquímica. Instituto de Geociências, Universidade Federal do Pará, Belém, 2022. Disponível em:http://repositorio.ufpa.br:8080/jspui/handle/2011/14827 . Acesso em:.https://repositorio.ufpa.br/handle/2011/14827Zircon U-Pb-Hf isotopic data from the main Mesoarchean units in the Ourilândia do Norte area (Carajás Province, Amazon Craton) were combined with a review of the main geological-structural, petrographic and geochemical aspects of these rocks, which allowed a redefinition of local stratigraphy, as well as a better understanding of the nature of the sources, based on geochemical modeling. In addition, a modern framework of the tectonostratigraphic correlations and the main events that led to the stabilization of the province was presented, as well as their implications for the origin of the plate tectonics. The Ourilândia granitoids are composed of interdigitated batholiths of sanukitoids and potassic granites, with subordinate TTG. (1) The TTG represent the oldest event in the area (2.92 Ga) and they are composed of tonalitic xenoliths (Mogno suite) and a porphyritic trondhjemite stock (Rio Verde suite), in which biotite is the main mafic mineral. The xenoliths are intensely deformed and the trondhjemite presents small mafic enclaves. The xenolith provided chondritic values of εHf(2.92 Ga) = +2.0 to –0.2 and was formed by partial melting of hydrated metabasalts, while the trondhjemite presented εHf(2.92 Ga) = +2.3 to –3.5 suggesting a more complex origin involving mixing between TTG-type melt and a subchondritic component, reflecting its longer crustal residence time (Hf-TDMC = 3.2–3.5 Ga) in relation to the xenolith (Hf- TDMC = 3.2–3.3 Ga). (2) The sanukitoids were grouped in the Ourilândia sanukitoid suite, which integrates the Arraias granodiorite (2.92 Ga) and the Ourilândia tonalite-granodiorite complex (2.88 Ga), which is composed of tonalites and granodiorites with subordinate quartz monzodiorite, quartz diorite and mafic enclaves. In general, these rocks show hornblende, biotite and epidote as the main mafic phases. The Arraias granodiorite is the oldest sanukitoid unit in the province and one of the oldest in the world. It provided εHf(2.92 Ga) values ranging from chondritic to subchondritic (+1.9 to –4.4) and can be generated by 29% melting of the mantle metasomatized by 40% TTG- type melt, under oxidizing conditions, leaving a residue composed of orthopyroxene, garnet, clinopyroxene and magnetite. Meanwhile, the Ourilândia complex provided values of εHf(2.88 Ga) = +3.4 to –2.0 and its different varieties of granitoids (including quartz monzodiorite) were formed from 18–33% melting of the mantle enriched by 20–40% TTG-type melt, under oxidizing conditions, leaving a residue composed of orthopyroxene, clinopyroxene, garnet, magnetite ±olivine. The mafic enclaves and the quartz diorite show distinct petrogenetic histories and were assumed to be a product of partial melting from the mantle metassomatized by fluids at lower pressures, outside the garnet stability zone. (3) The equigranularmonzogranite represents the largest unit in the area and was correlated with the Boa Sorte batholith (Canaã dos Carajás granitic suite). Its parental magma can be formed by 18% melting from a TTG-type trondhjemite (analogous to those of Água Azul do Norte) under relatively oxidizing conditions, leaving a residue composed of plagioclase, quartz, biotite, magnetite and ilmenite. The U-Pb data allowed to distinguish four zircon populations (3.04 Ga, 2.97 Ga, 2.93 Ga and 2.88 Ga). The youngest population was interpreted as the magmatic crystallization age (coeval to the Ourilândia complex) and provided subchondritic values of εHf(2.88 Ga) = –0.8 to – 4.1, which confirms its crustal origin. The 2.93 Ga population was interpreted as crystals C inherited from the TTG-type source and provided chondritic εHf(2.93 Ga) = +2.8 to –0.7 (Hf-TDMC = 3.1–3.4 Ga), indicating a shorter crustal residence time than the 2.88 Ga population (Hf-TDMC = 3.3–3.5 Ga). The populations dated at 3.04 Ga and 2.97 Ga were interpreted as xenocrystals with εHf(3.04 Ga) = –1.7 to –2.2 (Hf-TDMC = 3.5 Ga) and εHf(2.97 Ga) = +1.4 to –5.7 (Hf-TDMC = 3.3–3.7 Ga), respectively. (4) The high-Ti porphyritic granodiorite and the associated heterogranular monzogranite are closely related to the Boa Sorte granite and were grouped in the Tucumã granodiorite-granite suite, which has affinity with the Closepet (Dharwar craton, India) and the Matok (Pietersburg block, South Africa) granites. The high-Ti granodiorite can be formed by 30% melting from the mantle enriched with 40% of TTG-type melt under oxidizing conditions, leaving a residue composed of orthopyroxene, olivine, plagioclase, clinopyroxene and magnetite, with the participation of a component enriched in HFSEs, such as sediments, fluids and/or asthenosphere materials. The petrogenesis of the monzogranite of this suite involved mixing between 40% crust-derived magmas (Boa Sorte granite) and 60% enriched mantle-derived magmas (high-Ti granodiorite). A three-stage tectonic model is assumed to explain the C origin and isotopic signature of the studied granitoids. In general, the Hf-TDMC ranging from 3.7 to 3.1 Ga, indicating the existence of a Paleoarchean crustal component, which was generated in long-lived dome-and-keel tectonics (~600 Ma) and later recycled in the mantle allowing its enrichment from low-angle subduction in Mesoarchean (2nd setting), where the TTG-type granitoids and the first sanukitoid generation were formed at 2.92 Ga. Then, a short-lived collision (3rd setting) defined by the peak regional metamorphism (2.89–2.84 Ga) and associated with crustal thickening and slab breakoff allowed the origin of large volumes of mantle- and crust-derived magmas at ~2.88 Ga, where the ascent and emplacement were conditioned by shear zones.Acesso AbertoAttribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/GranitóidesPetrologiaTransição tectônicaArqueanoProvíncia CarajásTeseCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIAPETROLOGIA E EVOLUÇÃO CRUSTALGEOQUÍMICA E PETROLOGIA