Geochemical Features of Ore Fluid for Gold Deposits Related to Alkaline Rocks in China

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摘要 Fluidinclusionstudiesof5golddepositsconnectedwithalkalinerocksshowthatquartzseparatedfromauriferousquartzveinscontainsabundantthree-phaseCO2-NaCl-H2Oinclusionsandtwo-phaseCO2-dominatedones,measuring5-20umindiameter,Homogenizationtemperaturesofthefluidinclusionsaremostlywithintherangeof150-300℃,andthesalinities,mainly0.2wt%-12wt%(NaCl),Goldmineralizationsoccurredatdepthsof1.4-2.8km,Themoststrikingcharacteroffluidcompositionisthatamongthecations,Na^+indominant,followedbyK^+,Ca^2+,amongtheanions,Cl^-isslightlyhigherthanSO4^2-,Intheevaporate,H2Oisdominant,followedbyCO2,ThepHvaluesaremainlywithintherangeof6.5-8.5,indicatingthattheore-formingsolutionsarealkalineinnature.Thehydrogenandoxygenisotopicratiosindicatethattheorefluidiscomposedmainlyofmagmaticwater.Withthedroppingoftemperatureintheorefluid,thecontentsofCO2decreasedwhilethesalinityincreased.TherelationsbetweenAuandothercomponentsoftheorefluidarediscussedinthepaper,anditisconcludedthatinthesedeposits,Chlorides,H2S,SiO2,CO2,etc.inthefluidallareinvolvedinthemigrationandconcentrationofAu.
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出版日期 2000年03月13日(中国期刊网平台首次上网日期,不代表论文的发表时间)