BasedonelectronprobeanalysesofthemineralsandbulkcompositionoftheCenozoicvolcanicrocksfromYumenandHohXillithodistricts,Qinghai-Xizangplateau,theformingconditionsincludingthetemperatureandpressureofthoserocksarestudiedinthispaperAccordingtothethermodynamiccalculationresultsofmineral-meltequilibrium,thedepthoftheasthenospheresuperface(about75-130km)forthenorthernpartoftheQinghai-XizangplateauduringtheCenozoicissuggested.Finally,thispaperindicatesthattheCenozoicvolcanicrocksinthenorthernpartoftheQinghai-Xizangplateaumainlyconsistofshoshoniteseries.Theirformingtemperatureis630-1039℃andformingpressureisbetween2.3-4.0GPa.Therockswereformedintheintracontinentalorogenicbelt,ofwhichtheprimarymagmawasoriginatedfromaparticularenrichmentuppermantleandaccretedcrust-mantlebeltofdirectlyfromasthenosphericsuperfaceasaresultofpartialofpyrolite.
