Petrology of the Afonso Cláudio intrusive complex : new insights for the Cambro-Ordovician post-collisional magmatism in the Araçuaí-West Congo Orogen, Southeast Brazil.

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dc.contributor.authorAranda, Ramon de Oliveira
dc.contributor.authorChaves, Alexandre de Oliveira
dc.contributor.authorMedeiros Junior, Edgar Batista de
dc.contributor.authorVenturini Junior, R.
dc.date.accessioned2021-07-27T15:53:22Z
dc.date.available2021-07-27T15:53:22Z
dc.date.issued2020pt_BR
dc.description.abstractThe Afonso Cláudio Intrusive Complex (ACIC) is an igneous body located in the Espírito Santo state, Southeastern Brazil. It is inserted in the geological setting of the post-collisional G5 plutonic Supersuite, related to the extensional collapse stage of the Araçuaí-West Congo Orogen (AWCO). This study presents integrated data of field relationships, petrography, whole-rock geochemistry, zircon U-Pb geochronology and Lu-Hf isotopes that contributed to understand ACIC petrology. The ACIC intruded in pre-collisional orthogneisses and Nova Venécia Complex paragneisses of the AWCO. It is constituted by two monzogabbro/monzodiorite off-centered mafic cores surrounded by quartz monzonite. Mingling and mixing zones were mapped between these rocks, where jotunite and quartz mangerite occur. Host rock enclaves are observed enclosed by monzogabbro, monzodiorite and quartz monzonite, as well as monzogabbro/monzodiorite enclaves in the quartz monzonite. The ACIC rocks are enriched in LILE and LREE, showing alkali-calcic post-collisional geochemical signature. Zircon U-Pb dating revealed crystallization ages of 480.9 ± 3.2 Ma related to quartz monzonite and 496.5 ± 3.6 Ma to monzogabbro. Both rocks show negative zircon εHf (t) values (with average values of −11.78 and −10.41, respectively) and TDM ages of 1.79 Ga to quartz monzonite and 1.72 Ga to monzogabbro. Supported by presented data, two models can be proposed to the ACIC evolution during the collapse stage of the AWCO and both considering crustal contamination, mixing/mingling and assimilation associated to fractional crystallization. One is based on coeval mantle and crustal melting, with magmas interaction to generate an alkali-calcic magma, whose crystallization produced the monzogabbro and monzodiorite. With the continuity of the orogeny collapse, these mafic rocks would have melted and contributed to generate felsic magmas that crystalized as quartz monzonite. The second one argues in favor to mantle magma intrusion in a magmatic chamber where the nearby crustal rocks melted and the different magmas interacted between them. Monzogabbro and monzodiorite would have been generated by fractional crystallization of the mafic magmas and the quartz monzonite by crystallization of the felsic magmas. Due to the similarities among the post-collisional plutons in the AWCO, the proposed models may explain the petrogenesis of other similar plutons in this orogenic system.pt_BR
dc.identifier.citationARANDA, R. de O. et al. Petrology of the Afonso Cláudio intrusive complex: new insights for the Cambro-Ordovician post-collisional magmatism in the Araçuaí-West Congo Orogen, Southeast Brazil. Journal of South American Earth Sciences, v. 98, p. 102465, 2020. Disponível em: <https://www.sciencedirect.com/science/article/abs/pii/S0895981119303177>. Acesso em: 19 fev. 2021.pt_BR
dc.identifier.doihttps://doi.org/10.1016/j.jsames.2019.102465pt_BR
dc.identifier.issn0895-9811
dc.identifier.urihttp://www.repositorio.ufop.br/jspui/handle/123456789/13426
dc.identifier.uri2https://www.sciencedirect.com/science/article/abs/pii/S0895981119303177pt_BR
dc.language.isoen_USpt_BR
dc.rightsrestritopt_BR
dc.subjectMinglingpt_BR
dc.subjectMixingpt_BR
dc.subjectAFC processpt_BR
dc.subjectPost-collisional plutonspt_BR
dc.titlePetrology of the Afonso Cláudio intrusive complex : new insights for the Cambro-Ordovician post-collisional magmatism in the Araçuaí-West Congo Orogen, Southeast Brazil.pt_BR
dc.typeArtigo publicado em periodicopt_BR
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