Genesis of Rare Element Mineralized Granites in Southern China:Evidence from Melt and Fluid Inclusions

Rare element mineralized granites of the Yanshan period in Southern China are characterized by highcontents of SiO,NaO,O,KO,and F and are enriched in Nb,Ta,REE,W,Sn,Be and Li.Opinions dif-fered over whether they are of metasomatic or magmatic origin.In this paper,we present results of a studyon melt and fluid inclusions in topaz-albite feldspar granite from Limo Nb-Ta-W-Sn granite and414 Ta-Li albite granite.Our data,which come from 15 mineralized granites,provide strong supportmagmatic origin.Melt inclusions are recognized in both topaz and quartz,and are associated with primarygas-rich inclusions.Crystallites of a Nb(Ta)-bearing mineral and cassiterite are also commonly presentas inclusions in the topaz.Multiphase(melt+fluid)inclusions are observed in some quartz from granites andgranite-related pegmatite.Melt inclusions start to melt at a temperature of approximately 540 ℃ in topazand 650℃in quartz.Final homogenzation temperature is 700-900℃ in quartz,700-800℃ in topazand 440—550℃ for pri