Paleoproterozoic granitic magmatism in the northern São Francisco Craton, NE Brazil : new perspectives from geochemistry, zircon U–Pb geochronology and Hf isotopes.

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Autor(es): dc.creatorBarbosa, Rafael Gordilho-
Autor(es): dc.creatorLana, Cristiano de Carvalho-
Autor(es): dc.creatorZincone, Stéfano Albino-
Data de aceite: dc.date.accessioned2025-08-21T15:28:18Z-
Data de disponibilização: dc.date.available2025-08-21T15:28:18Z-
Data de envio: dc.date.issued2021-08-27-
Data de envio: dc.date.issued2021-08-27-
Data de envio: dc.date.issued2020-
Fonte completa do material: dc.identifierhttp://www.repositorio.ufop.br/jspui/handle/123456789/13603-
Fonte completa do material: dc.identifierhttps://www.sciencedirect.com/science/article/abs/pii/S0895981120305472-
Fonte completa do material: dc.identifierhttps://doi.org/10.1016/j.jsames.2020.103004-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/1015978-
Descrição: dc.descriptionThe Contendas-Mirante metavolcano-sedimentary sequence (CMS) has been studied by diverse authors but they did not emphasize the petrogenesis of the granitoid rocks that occur in the area. A set of eight fine-to-medium grained granitic plutons intrude the 3.2-3.4 Ga TTG rocks from the Gavião Block (GB) as well the 2.09-2.17 Ga meta-sedimentary rocks of the Contendas-Mirante metavolcano-sedimentary sequence. Two mineral assemblages were identified: i) quartz, K-feldspar, plagioclase and biotite as main phases and muscovite, zircon, apatite, chlorite, sericite, ilmenite and magnetite as accessories and ii) quartz, K-feldspar, plagioclase, biotite and muscovite as main phases and zircon, apatite, chlorite, sericite and ilmenite as accessories. Thus, it was possible to divide them between biotite-monzogranites and two-mica granites. Our results reveal that these granitoids are sodic and potassic peraluminous, leucocratic, calc-alkalic to alkali-calcic and are enriched in LREE in relation to the HREE. The biotite-monzogranites have slightly negative Eu anomalies whereas the two mica granites portray pronounced negative Eu anomalies. Both biotite-monzogranites and two-mica granites have Zr/Hf ratios between 21.90 and 35.59 which allowed their classification as moderately-to-highly fractionated granites. The biotite-monzogranites show geochemical similarities with Archean TTGs while the two-mica granites are akin to the post-Archean granitoids. The Rb and Y+Nb values indicate that the biotite-monzogranites are syn-collisional and the two-mica granites are post-collisional. The Rb/Sr and Rb/Ba ratios allowed the distinction of between clay-poor sources, related to the biotite-monzogranites and clay-rich sources related to the two-mica granites. U-Pb geochronological analysis indicated Journal Pre-proof 2 that the biotite-monzogranites have U-Pb concordia age of 2003 ± 10 Ma whereas the two mica granites portray U-Pb concordia age of 2056.7 ± 14 Ma, suggesting that both are Paleoproterozoic. Lu-Hf isotopic analysis in zircon showed that both granites have negative ƐHf(t) values (-33.5 - -8.1 for the biotite-monzogranites and -26.3 - -7.4 for the two-mica granites) which evidences their crustal origin. The biotite-monzogranites have TDM2(Hf) varying between 2.99 and 3.98 Ga while the two-mica granites have TDM2(Hf) between 3.02 and 3.64 Ga, suggestive of their derivation from Archean source rocks.-
Formato: dc.formatapplication/pdf-
Idioma: dc.languageen-
Direitos: dc.rightsrestrito-
Palavras-chave: dc.subjectGranites-
Palavras-chave: dc.subjectContendas-Mirante-
Palavras-chave: dc.subjectHighly fractionated-
Palavras-chave: dc.subjectCrustal derived-
Título: dc.titlePaleoproterozoic granitic magmatism in the northern São Francisco Craton, NE Brazil : new perspectives from geochemistry, zircon U–Pb geochronology and Hf isotopes.-
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