Granulite facies metamorphism, partial melting and metasomatism in the Wuhe Complex at the southeastern margin of the North China Block.

TheWuhecomplexislocatedatthesoutheasternmarginoftheNorthChinaBlockand belongstothePrecambrian metamorphicbasement．ItisexposedintheBengbuareaandits neighbourhood．TheWuhecomplexconsistsofthemetamorphosedigneousmaficandfelsicrocks andsupracrustalrocksassociated withthe Paleoproterozoicfoliated KＧfeldspargranitesan Mesozoicgranitoids,constitutingthe “Bengbuuplift”．Itsmainrocktypescompriseavariety oflithologies,including garnetamphibolite,garnetgranulite,rodingite,garnetＧplagioclaseＧ amphibolitegneiss,granitoidgneiss,micaschist,marble,quartziteandmetaＧsandstone．These rockscontainsimilarpeak metamorphic mineralssuchasgarnet,clinopyroxene,plagioclase, rutileandquartz．Asaresult,combinedwiththeirzirconUＧPbages,itissuggestedthatthey sufferfromacommonhighpressuregranulitefaciesmetamorphisminPalaeoproterozoic．The multiphasesolid inclusions within garnet porphyroblasts are discovered from the garnet amphibolite．Somemultiphasesolidinclusionsconsistofquartz,calcite,hornblendeandchlorite, withquartzandcalciteshowingasecondaryrimofhornblendeandchlorite．Theintergrowthsof quartz,KＧfeldspar,plagioclaseandbiotite,andrelated MSinclusionsingarnetshowthatthe Wuhecomplexexperiencesthehighpressuregranulitefaciesmetamorphism,accompanyingcloseＧ toＧcoevalpartialmeltingandheterogeneouscarbonatemetasomatism．Inaddition,therearelate alteredmineralssuchascalcite,epidoteandchlorite,andKＧfeldspar,plagioclase,quartz,biotite andamphiboledistributealongfracturesofgarnetsinthemetaＧbasites．Itissuggestedthatthe rocks undergo heterogeneously carbonateＧbearing hydrous melt/fluid metasomatism,and epidotizationandchloritization．ThecarbonatemetasomatismatthePalaeoproterozoicislikely responsiblefortheexceptionallyhighPbＧisotopiccompositionsregisteredbysomeofthemetaＧ basicrocksinthe metamorphicbasementinthearea,quitedifferentfrom thoseoftypical PrecambriangranuliteterrainsoroflowercrustalxenolithsintheNorthChinaBlock．