简介：TheDachangtin-polymetallicdistrict,Guangxi,China,isoneofthelargesttinorefieldsintheworld.Bothcassiterite-sulfideandZn-CuskarnmineralizationarehostedintheMid-UpperDevoniancarbonate-richsedi-mentsadjacenttotheunderlyingCretaceousLongxianggaigranite（91-97Ma）.TheLamoZn-CudepositisatypicalskarndepositinthedistrictandoccursatthecontactzonebetweentheUpperDevonianlimestoneandthegranite.Theoremineralsmainlyconsistofsphalerite,arsenopyrite,pyrrhotite,galena,chalcopyrite,andminormolybdenite.However,theageofmineralizationandsourceofthemetalsarenotwellconstrained.Inthisstudy,weusethemolybdeniteRe-Osdatingmethodandin-situPbisotopesofsulfidesfromtheLamodepositforthefirsttimeinordertodirectlydeterminetheageofmineralizationandthetracingsourceofmetals.SixmolybdenitesamplesyieldedamoreaccurateRe-Osisochronageof90.04-1.1Ma（MSWD--0.72）,whichismuchyoungerthanthereportedgarnetSm-Ndisochronageof95±11MaandquartzfluidinclusionsRb-Srisochronageof99±6Ma.ThisageisalsointerpretedastheageofZn-Cuskarnminer-alizationintheDachangdistrict.Further,inthisstudywefoundthatin-situPbisotopesofsulfidesfromtheLamodepositandfeldsparsinthedistrict＇sbiotitegraniteandgraniticporphyrydikeshaveanarrowrangeandanoverlapofPbisotopiccompositions（206pb/204pb18.417-18.594,207pb/204pb=15.641-15.746,and208pb/204pb=38.791-39.073）,suggestingthatthemetalsweremainlysourcedfromCretaceousgraniticmagma.