We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts,ilmenite,phlogopite,spinel,zircon,and uncommon minerals (titanite,calzirtite,anatase,baddeleyite and pyrochlore) of a newly discovered Late Cretaceous kimberlite (U-Pb zircon age 90.0 ± 1.3 Ma;2σ) named Osvaldo Fran(c)a 1,located in the Alto Paranaíba Igneous Province (APIP),southeastern Brazil.Pyrope grains are lherzolitic (Lherz-1,Lherz-2 and Lherz-3),harzburgitic (Harz-3) and wehrlitic (Wehr-2).The pyrope xenocrysts cover a wide mantle column in the subcratonic lithosphere (66-143 km;20-43 kbar)at relatively low temperatures (811-875 ℃).The shallowest part of this mantle is represented by Lherz-1 pyropes (20-32 kbar),which have low-Cr (Cr2O3 =1.74-6.89 wt.％) and fractionated middle to heavy rare earth elements (MREE-HREE) pattern.The deepest samples are represented by Lherz-2,Lherz-3,Harz-3,and Wehr-2 pyropes (36-43 kbar).They contain high-Cr contents (Cr2O3 =7.36-11.19 wt.％) and are char-acterized by sinusoidal (Lherz-2 and Wehr-2) and spoon-like (Lherz-3 and Harz-3) REE patterns.According to their REE and trace elements,pyrope xenocrysts have enriched nature (e.g.,Ce and Yb vs.Cr2O3),indicating that the cratonic lithosphere has been affected by a silicate melt with subalkaline/tholeiite composition due to their low Zr,Ti and Y concentrations.Besides minerals with typical kimber-litic signatures,such as ilmenite and zircon,the exotic compositions of phlogopite and ulv(o)spinel suggest an enriched component in the magma source.The formation of rare mineral phases with strong enrich-ment of light-REE (LREE) and high field strength elements (HFSE) is attributed to the late-stage kimber-litic melt.We propose a tectonic model where a thermal anomaly,represented by the low-velocity seismic anomaly observed in P-wave seismic tomography images,supplied heat to activate the alkaline magmatism from a metasomatized cratonic mantle source during the late-stages of Gondwana fragmen-tation and consequent South Atlantic Ocean opening.The metasomatism recorded by mineral phases is a product of long-lived recycling of subducted oceanic plates since the Neoproterozoic (Brasiliano Orogeny)or even older collisional events,contributing to the exotic character of the Osvaldo Fran(c)a 1 kimberlite,as well as to the cratonic lithospheric mantle.

Luísa D.V.Carvalho;Tiago Jalowitzki;Ricardo Scholz;Guilherme O.Gon(c)alves;Marcelo Peres Rocha;Rogério Silvestre Pereir;Cristiano Lana;Marco Paulo de Castro;Gláucia Queiroga;Reinhardt A.Fuck

Universidade Federal de Ouro Preto (UFOP),Escola de Minas,Departamento de Geologia,Campus Morro do Cruzeiro,35400-000 Ouro Preto,MG,Brazil;Universidade de Brasília (UnB),Instituto de Geociêndas,Campus Universitário Darcy Ribeiro,70910-900 Brasília,DF,Brazil

地学前缘（英文版）

[1]Luísa D.V.Carvalho;Tiago Jalowitzki;Ricardo Scholz;Guilherme O.Gon(c)alves;Marcelo Peres Rocha;Rogério Silvestre Pereir;Cristiano Lana;Marco Paulo de Castro;Gláucia Queiroga;Reinhardt A.Fuck-.An exotic Cretaceous kimberlite linked to metasomatized lithospheric mantle beneath the southwestern margin of the Francisco Craton,Brazil)[J].地学前缘（英文版）,2022(01):182-203

kimberlite,phlogopite,calzirtite,baddeleyite,Osvaldo,Parana,Pyrope,lherzolitic,Lherz,harzburgitic,Harz,wehrlitic,Wehr,pyrope,subcratonic,shallowest,pyropes,spoon,tholeiite,kimber,litic,ulv,Brasiliano,Orogeny

An,exotic,Cretaceous,linked,metasomatized,lithospheric,mantle,beneath,southwestern,margin,Francisco,Craton,Brazil,major,trace,compositions,concentrates,comprising,garnet,xenocrysts,ilmenite,spinel,zircon,uncommon,minerals,titanite,anatase,pyrochlore,newly,discovered,Late,Pb,Ma,named,located,Alto,Igneous,Province,APIP,southeastern,grains,wide,column,lithosphere,kbar,relatively,temperatures,part,this,represented,by,which,have,Cr2O3,wt,fractionated,middle,heavy,rare,earth,elements,MREE,HREE,deepest,samples,They,contain,high,contents,acterized,sinusoidal,like,patterns,According,their,enriched,Ce,Yb,indicating,that,been,affected,silicate,melt,subalkaline,due,Zr,Ti,concentrations,Besides,typical,signatures,such,suggest,component,source,formation,phases,strong,light,LREE,field,strength,HFSE,attributed,propose,tectonic,model,where,thermal,anomaly,velocity,seismic,observed,wave,tomography,images,supplied,heat,activate,magmatism,from,during,stages,Gondwana,fragmen,tation,consequent,South,Atlantic,Ocean,opening,metasomatism,recorded,product,long,lived,recycling,subducted,oceanic,plates,since,Neoproterozoic,older,collisional,events,contributing,character,well

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