The southern S?o Francisco Paleocontinent(SFP)comprises Archean nuclei and Paleoproterozoic com-plexes encompassing magmatic arcs juxtaposed during a Rhyacian to Orosirian orogenic event.The Juiz de Fora Complex(JFC)represents an imbricated thrust system that comprises orthogranulites with a wide compositional range formed in an intra-oceanic setting during the Siderian to the Orosirian and later accreted to the southeastern margin of the SFP.Here we report new petrological,geochemical,whole-rock Nd and Sr data,as well as zircon U-Pb ages from felsic and mafic orthogranulites from the JFC.The new data is combined with a regional compilation that enables an evaluation of the interaction between magmatism and orogenetic episodes in the context of the consolidation of S?o Francisco Paleocontinent during the Rhyacian-Orosirian.Pre collisional Island Arc tholeiites(IAT),Tonalites-Tron dhjemites-Granodiorites(TTGs)and sanukitoid magmatism occurred from 2200 Ma to 2085 Ma.This was followed by post-collisional magmatism,which is represented by hybrid granitoids coeval with the emplacement of E-MORB basic rocks.Crustal signatures for the Rhyacian to Orosirian evolution are highlighted by the dominance of negative εNd(t)associated with Meso-to Neoarchean Nd TDM model ages as well as inherited zircon grains from the hybrid granitoids.The JFC is extensively highlighted in the lit-erature as a primitive intra-oceanic arc,but here we propose the reworking or recycling of ancient crustal segments within the mature arc stage of the JFC,suggesting a Mesoarchean crustal source involved in the JFC evolution.

Rasec Almeida;Vitalino Elizeu;Henrique Bruno;Samuel Moreira Bersan;Lucas Eduardo de Abreu Barbosa Araujo;Ivo Dussin;Claudio de Morisson Valeriano;Carla Neto;Monica Heilbron

Universidade do Estado do Rio de Janeiro,Faculdade de Geologia,Tektos-Grupo de Pesquisa em Geotect?nica,Rua S?o Francisco Xavier 524,Maracan?,Rio de Janeiro,Brazil;Laboratório de Geocronologia e Isótopos Radiogênicos,Universidade do Estado do Rio de Janeiro,Rua S?o Francisco Xavier 524,Maracan?,Rio de Janeiro,Brazil

地学前缘（英文版）

[1]Rasec Almeida;Vitalino Elizeu;Henrique Bruno;Samuel Moreira Bersan;Lucas Eduardo de Abreu Barbosa Araujo;Ivo Dussin;Claudio de Morisson Valeriano;Carla Neto;Monica Heilbron-.Rhyacian-Orosirian tectonic history of the Juiz de Fora Complex:Evidence for an Archean crustal reservoir within an island-arc system)[J].地学前缘（英文版）,2022(05):350-369

Rhyacian,Orosirian,Juiz,Fora,Paleocontinent,juxtaposed,orthogranulites,Siderian,orogenetic,tholeiites,Tonalites,Tron,dhjemites,Granodiorites,TTGs,sanukitoid,Mesoarchean

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