简介：Twokindsofmyloniteseriesrocks,felsicandmafic,havebeenrecognizedintheNW-strikingshearzoneoftheJiapigougoldbelt.Duringductiledeformation,alargeamountoffluidinteractedintensivelywiththemyloniteseriesrocks:plagioclasesweresericitizedandtheAnvaluesdeclinedrapidly,finallyallofthemweretransformedtoalbites;darkmineralsweregraduallyreplacedbychlorites(mostlyripidolite).Meanwhile,large-scaleandextensivecarbonationalsotookplace,andthecarbonatizationmineralsvariedfromcalcitetodolomiteandankeritewiththedevelopmentofdeformation.Theδ^13Cvaluesofthecarbonatesare-3.0‰--5.6‰suggestingadeepsourceofcarbon.Theductiledeformationisnearlyaniso-volumeone(fv=1).Withtheenhancementofsheardeformation,SiO2inthetwomyloniteseriesrockswasdepleted,whilevolatilecomponentssuchasCO2andH2O,andsomeore-formingelementssuchasAuandSwereobviouslyenriched.ButitisnotedthattheenrichmentofAuinboththemyloniteseriesrocksdidnotreachthepaygradeofgold.ThereleasedSiO2fromwater-rockinteractionsoccurredintheformofcolloidsandabsorbedgoldinthefluid.Whenbrittlestructureswereformedlocallyintheductileintheductileshearzone,theore-formingfluidsmigratedtothestructuresalongmicrofractures,andprecipitatedauriferousquartzbecauseofreductionofpressureandtemperature.Fluidinclusionstudyshowsthatthetemperatureandpressureoftheore-formingfluidsare245-292℃and95.4-131.7MParespectively;thesalinityis12.88-16.33wt%NaCl;thefluid-phaseisrichinCa^2+,K^+,Na^+,Mg^2+,F^-andCl^-,whilethegaseousphasesarerichinCO2andCH4.TheδDandδ^18Ovaluesoftheore-formingfluidare-84.48‰--91.73‰and-0.247‰-+2.715‰respectively,suggestingthatthefluidiscomposedpredominantlyofmeteoricwater.