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Alexandre de Oliveira Chaveshttp://lattes.cnpq.br/9315399347529162Edgar Batista de Medeiros JúniorJorge Geraldo Roncato JúniorRubia Ribeiro VianaStefano Albino Zinconehttp://lattes.cnpq.br/4439149377739758Daniel Andrade Miranda2020-08-12T13:59:27Z2020-08-12T13:59:27Z2020-07-07http://hdl.handle.net/1843/33966https://orcid.org/0000-0001-9242-6698The Itapecerica supracrustal succession in the southern São Francisco Craton, around Itapecerica (MG), appear as elliptical geophysical anomalies containing, in their internal portions, sillimanite-cordierite-garnet-biotite gneiss (khondalite) with anatectic record, quartzite, graphite schist and banded iron formation, whose protoliths from oceanic basin have ages in the context of the Rhyacian-Orosirian orogeny. With mixed pelite to wacke compositions and organic matter accumulation, part of the original sediments comes from the erosion of different sources of an active continental margin setting. Metaultramafic rocks and amphibolites wtih tholeiitic affinity and E-MORB signature occur associated to this succession, suggesting to be meta-ophiolitic fragments. During metamorphic peak, the organic matter became graphite (δ13C -21.23 to -27.89 ‰) around 729 ºC and the aluminous sediments became khondalite at 715–772 ºC and 5.5– 7.5 kbar around 2090 ± 26 Ma (monazite U-Th-PbT). These conditions represent the transition of amphibolite to granulite facies in which the khondalite and amphibolite underwent anatexis during continental collision with crustal thickning followed by tectonic exgumation to generated the Água Rasa metagranite of the external part of the anomalies (εNd(t) -0.5 to -2.7 and 87Sr/86Sr(t) 1.04 to 1.08) at 2077 ± 24 Ma (monazite UTh-PbT). The post-peak decompressional stage due to orogen collapse triggered hydrothermal processes with percolation of C-O-H fluids, leading to the graphite recrystallization around 611 ºC. The decompression process proceeded generating the Água Rasa metagranite between 1941±23 Ma (monazite U-Th-PbT) and 1934±74 Ma (zircon U-Pb). This process is also recorded in the khondalite at 1937 ± 32 Ma (monazite U-Th-PbT) from the resetting of the monazite U-Th-Pb system during the orogenic collapse. A possible suture zone in the Itapecerica/Cláudio region formed by the collision between Divinópolis and Campo Belo/Bonfim complexes during the Rhyacian-Orosirian orogeny, involving the Itapecerica oceanic basin alongside Cláudio Shear Zoneand forward to Minas Basin, is a suggestive geological setting of the investigated region. Similarities between the khondalite rocks of this study and of the North China suggest that the São Francisco-Congo Craton was near the North China Craton in the supercontinent Columbia for the 2.1–1.9 Ga period.A sucessão supracrustal de Itapecerica no Sul do Cráton São Francisco, ao redor de Itapecerica (MG), revela-se em anomalias geofísicas elípticas contendo, nas suas porções internas, sillimanita-cordierita-granada-biotita gnaisse (khondalito) com registro anatético, quartzito, grafita xisto e formação ferrífera bandada, cujos protólitos são de bacia oceânica com idades no contexto da orogenia Riaciano-Orosiriana. Com composições mistas de pelito a grauvaca e acúmulo de matéria orgânica, parte dos sedimentos originais são proveniente da erosão de diferentes fontes de ambiente de margem continental ativa. Rochas metaultramáficas e anfibolitos com afinidade toleítica e assinatura E-MORB ocorrem associados a esta sucessão, sugerindo se tratarem de fragmentos meta-ofiolíticos. Durante o pico do metamorfismo, a matéria orgânica se transformou em grafita (δ13C -21,23 a -27,89 ‰) em torno de 729 ºC e os sedimentos aluminosos se transformaram em khondalito a 715-772 ºC e 5,5-7,5 kbar há 2090 ± 26 Ma (U-Th-PbT em monazita). Essas condições representam a transição da fácies anfibolito para granulito, nas quais o khondalito e o anfibolito sofreram anatexia durante colisão continental com espessamento crustal seguido de exumação tectônica e geraram o metagranito Água Rasa da parte externa das anomalias (εNd(t) -0,5 a -2,7 e 87Sr/86Sr(t) 1,04 a 1,08) há 2077 ± 24 Ma (U-Th-PbT em monazita). O estágio descompressivo pós-pico decorrente do colapso do orógeno disparou processos hidrotermais com percolação de fluidos C-O-H, recristalizando a grafita em torno de 611 ºC. O processo de descompressão continuou gerando o metagranito Água Rasa entre 1941 ± 23 Ma (U-Th-PbT em monazita) e 1934 ± 74 Ma (zircão U-Pb), processo este também detectado no khondalito há 1937 ± 32 Ma (U-Th-PbT em monazita) a partir do reset do sistema U-Th-Pb da monazita durante o colapso orogênico. Uma possível zona de sutura na região de Itapecerica/Cláudio formada pela colisão entre os complexos Divinópolis e Campo Belo/Bonfim durante a orogenia Riaciano-Orosiriana, envolvendo a bacia oceânica de Itapecerica com prolongamento pela Zona de Cisalhamento de Cláudio em direçãoàBacia Minas, é um cenário geológico sugestivo para a região investigada. As semelhanças entre as rochas khondalíticas deste estudo e as do Norte da China sugerem que o Cráton São Francisco-Congo estava próximo ao Cráton do Norte da China no supercontinente Columbia durante o período de 2.1-1.9 Ga.FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas GeraisCAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorengUniversidade Federal de Minas GeraisPrograma de Pós-Graduação em GeologiaUFMGBrasilIGC - DEPARTAMENTO DE GEOLOGIAPetrologia – Itapecerica (MG)Geoquímica – Itapecerica (MG)Metamorfismo (Geologia)Alteração hidrotermalTempo geológicoGrafitaKondalitoMetagranitoAnfibolitoMetaperidotitoOfiolitoPetrologiaGeoquímicaGeocronlogiaTrajetória P-T-tMetamorfismoHidrotermalismoProveniênciaAnatexiaCráton São FranciscoGraphite schists, khondalites, metagranites and meta-ophiolites from Itapecerica (MG-Brazil) : records of rhyacian-orosirian orogeny in Southern São Francisco CratonGrafita xistos, kondalitos, metagranitos e meta-ofiolitos de Itapecerica (MG-Brasil): registros da orogenia riaciano-orosiriana no Sul do Cráton São Franciscoinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFMGinstname:Universidade Federal de Minas Gerais (UFMG)instacron:UFMGORIGINALTese_FINAL.pdfTese_FINAL.pdfapplication/pdf16408891https://repositorio.ufmg.br/bitstream/1843/33966/1/Tese_FINAL.pdff3dcd8f269540537e35b56ac6bc754cdMD51LICENSElicense.txtlicense.txttext/plain; charset=utf-82119https://repositorio.ufmg.br/bitstream/1843/33966/2/license.txt34badce4be7e31e3adb4575ae96af679MD521843/339662020-08-12 10:59:27.448oai:repositorio.ufmg.br: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Repositório InstitucionalPUBhttps://repositorio.ufmg.br/oaiopendoar:2020-08-12T13:59:27Repositório Institucional da UFMG - Universidade Federal de Minas Gerais (UFMG)false
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