Metavolcanic rocks are well-exposed in the Kribi area within the Nyong Group,Congo craton,but their origin,age,and tectonic significance are poorly known.Here we report integrated field mapping and petrography,geochemistry,and LA-ICP-MS zircon U-Pb ages of these metavolcanic rocks to constrain their petrogenesis and geodynamic implications.The studied rocks consist of mafic granulite,garnet-amphibole gneiss,and garnet-bi-otite gneiss,and occur interbanded with sharp contact and intruded by syenite dyke.These metavolcanic rocks are classified as MORB-like tholeiitic to calc-alkaline basalts,basaltic andesite,and rhyodacite rocks with within-plate setting geochemical signatures.The metabasite rocks(basalt to basaltic andesite protolith)are likely the equiv-alent of a spinel peridotite product representing～2-5％partial melting of metasomatized mantle source,while the metarhyodacite rocks are derived from the fractional crystallization of the same parental magma.Zircon U-Pb data revealed that the rhyodacite rocks initially formed at 2671±51 Ma and underwent later metamorphism at 2065±55 Ma.The Neoarchean protolith age is compa-rable to the ca.2628 Ma tholeiitic magmatism and ca.2666 Ma high-K granites,suggesting bimodal Neoarchean magmatic event within the Ntem Complex,while the metamorphic ages fall within the ca.2100-2000 Ma high-grade tectono-metamorphic event attributed to Eburnean/Trans-Amazonian orogeny.At the regional scale,metavolcanic rocks with similar origins and ages are doc-umented in the Sao Francisco Craton in Brazil,suggesting comparable geodynamic evolution on both sides of the south Atlantic during the Paleoproterozoic.

Hermine Mvodo;Sylvestre Ganno;Gus Djibril Kouankap Nono;Donald Hermann Fossi;Philomene Estelle Nga Essomba;Marvine Nzepang Tankwa;Jean Paul Nzenti

Department of Earth Sciences,University of Yaoundé I,P.O.Box 812,Yaoundé,Cameroon;Department of Geology,HTTC,University of Bamenda,P.O.Box 39,Bambili,Bamenda,Cameroon;Institute for Geological and Mining Research,P.O.Box 4110,Yaoundé,Cameroon;Faculty of Mines and Petroleum Industries,University of Maroua,Kaélé 08,Maroua,Cameroon

地球化学学报（英文版）

[1]Hermine Mvodo;Sylvestre Ganno;Gus Djibril Kouankap Nono;Donald Hermann Fossi;Philomene Estelle Nga Essomba;Marvine Nzepang Tankwa;Jean Paul Nzenti-.Petrogenesis,LA-ICP-MS zircon U-Pb geochronology and geodynamic implications of the Kribi metavolcanic rocks,Nyong Group,Congo craton)[J].地球化学学报（英文版）,2022(03):470-495

Kribi,Nyong,Metavolcanic,otite,interbanded,tholeiitic,rhyodacite,metabasite,metarhyodacite,Ntem,Eburnean,umented

Petrogenesis,LA,ICP,zircon,Pb,geochronology,geodynamic,implications,metavolcanic,rocks,Group,Congo,craton,well,exposed,area,within,their,tectonic,significance,poorly,known,Here,report,integrated,field,mapping,petrography,geochemistry,ages,these,constrain,petrogenesis,studied,consist,mafic,granulite,garnet,amphibole,gneiss,occur,sharp,contact,intruded,by,syenite,dyke,These,classified,MORB,calc,alkaline,basalts,basaltic,andesite,plate,setting,geochemical,signatures,protolith,likely,equiv,alent,spinel,peridotite,product,representing,partial,melting,metasomatized,mantle,source,while,derived,from,fractional,crystallization,same,parental,Zircon,data,revealed,that,initially,formed,Ma,underwent,later,metamorphism,Neoarchean,magmatism,high,granites,suggesting,bimodal,magmatic,event,Complex,metamorphic,fall,grade,tectono,attributed,Trans,Amazonian,orogeny,regional,scale,similar,origins,doc,Sao,Francisco,Craton,Brazil,comparable,evolution,both,sides,south,Atlantic,during,Paleoproterozoic

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