摘要
Ti-richgarnetisfoundwithincalciticijolitefromtheOkacarbonatitecomplexinCanada,whichischaracterizedby58%–73%andraditecomponent（2.12wt.%–4.18wt.%TiO2）andclassifiedasmelanite.Thegarnetdisplayscomplexzoningandcontainsabundanthighfieldstrengthelements（HFSEs）andrareearthelements（REEs）.Threegroups（Ⅰ,Ⅱ,Ⅲ）havebeenidentifiedbasedontheirpetrographicnature.ComparedtogroupsⅡandⅢ,GroupⅠgarnetcorescontainhigherTiO2,MgO,HFSE,andREEandlowerSiO2abundances.Thedistinctchemicalandpetrographicsignaturesoftheinvestigatedgarnetscannotbeattributedtosimpleclosedsystemcrystallization,buttheyareconsistentwiththemulti-pulsemagmamixing.CombinedwithpreviouslyreportedU-Pbagesforapatitefromthecalciticijolite,atleastthreestagesofmagmaevolutionandsubsequentmixinghavebeeninvolvedinthegenerationofcalciticijoliteatOka.Theearly-formedmeltthatgeneratedGroupIgarnetcorewaslatermixedwithatleasttwosmall-volume,moreevolvedmelts.Theintermediatestagemeltformedtheremaininggarnetalongwithsomepyroxene,calcite,nepheline,andapatiteat127±3.6Ma.Theyoungest,mostevolvedmeltgeneratedthemajorityofpyroxene,calcite,nepheline,andapatitewithinthecalciticijoliteat115±3.1Ma.
出版日期
2016年04月14日（中国期刊网平台首次上网日期，不代表论文的发表时间）
