FCT - Faculdade de Ciências e Tecnologia

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Navegando FCT - Faculdade de Ciências e Tecnologia por Assunto "Anicuns-Itaberaí metavolcanosedimentary sequence"

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    Mapeamento geológico integrado 1:50.000 da região da Serra da Jiboia (GO) - área 4
    (Universidade Federal de Goiás, 2023-02-15) Santos, Daniel Carelli Batista; Carvalho, Franklin Williams Silva de; Lima, Gabriel Dutra de; Temporim, Filipe Altoé; Temporim, Filipe Altoé; Oliveira, Ítalo Lopes de; Arab, Paola Bruno
    The present work had as objective the geological mapping in the region of Nazário - GO from the accomplishment of systematic works that integrated data from remote sensing (orbital images), geophysical, geochemical, lithological, petrographic, structural and geoenvironmental surveys. The result of the integrated work was the geological cartography of Neoproterozoic units associated to the Goiás Magmatic Arc: Metavolcanosedimentary Anicuns-Itaberaí Sequence, Anápolis-Itauçu Complex, Creoulos Granite and Santa Bárbara Anorthositic Complex. Four deformational stages were recognized in the area: D1 represents E-W compression associated with regional folds with eastward vergence; D2 is the E-W compression refolding of the D1 progression; D3 characterizes shallower crustal level change during deformation progression and generates N-S lateral shortening of the D2 deformation and N-S axis crenulations; D4 represents the ruptile-ductile stage of E-W compression with formation of shear zones and thrust faults. In general, the rocks of the Anicuns-Itaberaí Metavolcanosedimentary Sequence in the study area are metamorphosed between green schist and amphibolite facies with retrometamorphism to green schist facies. The region is relevant for understanding the evolution of the Brasília Belt, as the rocks are linked to tectonic and magmatic events that started with in the formation of the Magmatic Arco f Goias. The study area is economically interesting due to the presence of mineral occurrences with potential for metallurgy (manganese and iron) and civil construction (sand, gravel, crushed stone and ornamental rocks).
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    Metamorfismo da sequência Anicuns-Itaberaí na região de Nazário-GO
    (Universidade Federal de Goiás, 2024-07-22) Brod, Gabriel Silveira; Vieira, Otávio Passo; Melo, Rodrigo Prudente de; Temporim, Filipe Altoé; Temporim, Filipe Altoé; Cavalcanti, Débora Ezequiel; Grella, João Victor
    The Anicuns-Itaberaí Sequence is one of the metavolcanosedimentary sequences that make up the Arenópolis Magmatic Arc. However, even with the abundance of research found in the literature related to geochemical, isotopic and geochronological aspects, there is still little material on petrology and structural geology with a focus on the metamorphic evolution of these rocks, which makes the tectono-metamorphic evolution of these sequences still poorly understood. This work aimed to establish, through geological mapping, structural interpretation and petrological studies, a greater understanding of the metamorphic conditions (P-T) that the rocks of the Anicuns-Itaberaí Sequence were subjected to during the metamorphic evolution of the Brasília belt. The results of this work include geological mapping on a scale of 1:50,000 of the region bordering the municipalities of Anicuns, Avelinópolis, Nazário and Palmeiras de Goiás. It also includes the integration of structural, microstructural and petrological data, and the creation of compositional maps of two samples of garnet-chlorite-biotite-muscovite schist from the area that were made using XMapTools software from electron microprobe data. The mineral assemblage of these rocks, given by garnet + plagioclase + biotite + muscovite + quartz + chlorite, was modeled geothermobarometrically using the Bingo-Antidote extension. The modeling results suggest that the metamorphic peak occurred in amphibolite facies conditions (staurolite zone), with retrometamorphism during crustal exhumation to green schist facies conditions. The results show small differences in values between the samples. In sample 23GO_022-P1 the conditions obtained were 630.9 °C and 1.007 GPa for the peak of metamorphism and 536.6 °C and 0.588 GPa for retrometamorphism, while for sample 23GO_025-T1 the conditions were 654.2 °C and 1.198 GPa for the metamorphic peak and 569.9 °C and 0.703 GPa for retrometamorphism. These values indicate that, although there is a small difference between the P-T results between the two samples, the P-T amplitude between the metamorphic peak and the retrometamorphism are very similar for the two samples, which suggests that these differences may be related to different levels of burial between the two samples during the metamorphic process. Finally, it should be emphasized that the data presented in this work provides new information on the geological evolution of these rocks and also shows the need for more studies of this type in the area, including geochronological data on metamorphic rocks in order to better understand the relationship between metamorphism and the tectonic events that affected the region.