JournalJournalofGeochemicalExploration54(1995)87-136EpithermalgolddepositsofthesouthwestPacificN.C.Whitea,M.J.Leakeb,S.N.McCaughey‘,B.W.ParrisdaBHPMineralsInternationalExplorationInc.,229ShepherdsBushRoad,LondonW67AN.UKbb’‘Larena”,SpillersRoad,Macclesjield,Vie.3782,Australia’BHPMineralsPty.Ltd.,P.O.Box425,SpringHill,Qld.4004,Australiad26JeffreyStreet,LowerTemplestowe,Vie.3IO7,AustraliaReceivedReceived18July1994;accepted11April1995AbstractAbstractSinceSincethefreeingofthemarketpriceofgoldin1971,explorationforepithermalgolddepositsinthesouthwestPacificregionhashasbeenintense,andhasbeenencouragedbysomemajorsuccesses.Sufficientdiscoverieshavebeenmadetosummarisewhathashasbeenfoundtodate,andtoassesswhatimplicationsmaybedrawnforfutureexploration.Dataaretabulatedfor137epithermalpreciouspreciousmetaldepositsandprospectsinAustralia(30),Fiji(2),Indonesia(43),NewZealand(22))PalauandYap(2),PapuaNewNewGuinea(18),thePhilippines(19),andSolomonIslands(1).ComparisonComparisonofthecharacterofepithermaldepositsinthesouthwestPacificwiththoseinotherregions(e.g.,thenortheasternPacificPacificmargin)suggeststhattheyareinmostrespectssimilarwith,however,threedifferences:(i)throughmuchoftheregion(especially(especiallythePhilippinesandIndonesia)low-sulfidationstyledepositscommonlyshowcharacteristicssuggestiveofformationatdeeperlevelsthanistypicalelsewhere;(ii)high-sulfidationdepositsappeartobemorecommonthanalongthenortheastPacificPacificmargin;(iii)manyofthelargestdepositsshowatypicalfeatures,particularlythosesuggestiveofatransitiontoporphyryorormesothermalconditions,orindicatingoverprintingofanepithennalsystemonaporphyryenvironment.ThesedifferencescancanbepartlyunderstoodintermsofthetectonicsettingandevolutionofthevolcanicarcsofthesouthwestPacific,andtheconsequentconsequenthydrologicalconditionsthatexistedduringmineralization.TheTheresultsofexplorationinthesouthwestPacificindicatethat,whiletheprinciplesofformationofepithermaldepositsstillapply,apply,depositmodelsd