安徽铜陵新桥铜-金矿床的He、Ar同位素组成及其意义
|
摘要
对安徽铜陵新桥铜 金矿床层状矿体和块状矿体的黄铁矿进行了流体包裹体的He、Ar同位素研究。结果表明,成矿流体的N(40Ar)/N(36Ar)≈238～293,N(3He)/N(4He)≈1 03～1 23Ra,与大气饱和水(包括大气降水和海水)的特征值N(3He)/N(4He)=1Ra,N(40Ar)/N(36Ar)=295 5非常接近,表明成矿流体含大气降水和海水,这与野外地质特征也相符合,反映了成矿流体来自海底喷流(热水)沉积作用过程,这一认识为该区铜 金矿床可能的海底热液喷流成因提供了新的证据。
The ore genesis model of the Xinqiao Cu-Au deposit in Tongling of Auhui Province has long been in dispute, and the major debate focuses on whether the stratiform orebodies formed during the Yanshanian magmatic-hydrothermal event or they were products of carbonferious syn-sedimentary exhalative-hydrothermal event. The paper presents helium isotope data from fluid inclusions of five pyrites. The pyrites were collected from the stratiform orebodies in the deposit, and their ()~3He/()~4He ratios are significantly higher than 1, range from 1.02 to 1.22Ra, which indicateds a mantle component in the responsible hydrothermal fluids. It is suggested that the ore-forming fluids were a mixture of deep circulating seawater and a mantle-derived fluids, which are similar to many of those modern submarine hydrothermal fluids.The data provide a new evidence that favour the submarine exhalative-hydrothermal origin for the stratiform mineralization in Xinqiao Cu-Au deposit.
The ore genesis model of the Xinqiao Cu-Au deposit in Tongling of Auhui Province has long been in dispute, and the major debate focuses on whether the stratiform orebodies formed during the Yanshanian magmatic-hydrothermal event or they were products of carbonferious syn-sedimentary exhalative-hydrothermal event. The paper presents helium isotope data from fluid inclusions of five pyrites. The pyrites were collected from the stratiform orebodies in the deposit, and their ()~3He/()~4He ratios are significantly higher than 1, range from 1.02 to 1.22Ra, which indicateds a mantle component in the responsible hydrothermal fluids. It is suggested that the ore-forming fluids were a mixture of deep circulating seawater and a mantle-derived fluids, which are similar to many of those modern submarine hydrothermal fluids.The data provide a new evidence that favour the submarine exhalative-hydrothermal origin for the stratiform mineralization in Xinqiao Cu-Au deposit.
引文
[1] StuartFM,BurnardPG,TaylorRP,etal Resolvingmantleandcrustalcontributionstoancienthydrothermalfluids:He-ArisotopesinfluidinclusionsfromDaeHwaW-Momineralization,SouthKorea[J].GeochimCosmochimActa,1995,59:4663—4673
[2] 杨兵,王之田 铜官山铜矿床新类型矿体的发现及矿床成因模式[J].矿床地质,1985,4(4):41—13
[3] 徐克勤,朱金初 我国东南部几个断裂拗陷带中沉积(或火山沉积)热液叠加类铁铜矿床成因的探讨[J].福建地质,1978,4:1—68
[4] 顾连兴,徐克勤 论长江中下游中石炭世海底块状硫化物矿床[J] 地质学报,1986,60(2):176—188
[5] GuLianxin,HuWenxuan,HeJinxiang,etal Regionalvar iationsinorecompositionandfluidfeaturesofmassivesulphidedepositsinSouthChina:Implicationsforgeneticmodelling[J].Episodes,2000,23(2):110—118
[6] ZhaiYS,XiongYL,YaoSZ,etal MetallogenyofcopperandirondepositsintheeasternYangtzeCraton,east-centralChina[J].OreGeologyReviews,1996,11:229—248
[7] XuG,ZhouJ TheXinqiaoCu-S-Fe-AudepositintheTonglingmineraldistrict,China:synorogenicremobilizationofastratiformsulfidedeposit[J].OreGeologyReviews,2001,18:77—94
[8] StuartFM,TurnerG,DuckworthRC,etal Heliumisotopesastracersoftrappedhydrothermalfluidsinoceanfloorsulfides[J].Geology,1994,22:823—826
[9] BaptistePJ,FouquetY AbundanceandisotopiccompositionofheliuminhydrothermalsulfidesfromtheEastPacificRiseat13°N[J].GeochimCosmochimActa,1996,60:87—93
[10]TrullTW,KurzMD,JenkinsWJ Diffusionofcosmogenic3Heinolivineandquartz:implicationsforsurfaceexposuredating[J].EarthPlanetSciLett,1991,103:241—256
[11]QiuHN 40Ar/39ArdatingofthequartzsamplesfromtwomineraldepositsinwesternYunnan(SWChina)bycrushinginvacuum[J].ChemGeol,1996,127:211—222
[12]TurnerG,StuartF Helium/heatratiosanddepositiontemperaturesofsulfidesfromtheoceanfloor[J].Nature,1992,357:581—583
[13]TurnerG,BurnardPB,FordJL,etal Tracingfluidsourcesandinteraction[J] PhilTransRSocLondA,1993,344:127—140
[14]BurnardPG,HuR,TurnerG,etal Mantle,crustalandatmosphericnoblegasesinAilaoshangolddeposits,YunnanProvince,China[J].GeochimCosmochimActa,1999,63:1595—1604
[15]曾普胜,裴荣富,侯增谦,等 安徽铜陵地块沉积-喷流块状硫化物矿床[J].矿床地质,2002,21(增刊):532—535.
[16]WincklerG,Aeschbach HertigW,KipferR,etal ConstraintsonoriginandevolutionofRedSeabrinesfromheliumandargonisotopes[J].EarthPlanetSciLet,2001,184:671—683
[17]曾志刚,秦蕴珊,翟世奎 大西洋中脊TAG热液区硫化物中流体包裹体的He-Ne-Ar同位素组成[J].中国科学D辑,2000,30(6):628—633
[18]佟景贵,李胜荣,肖启云,等 贵州遵义中南村黑色岩系黄铁矿的成分标型与成因探讨[J].现代地质,2004,18(1):41—47
[19]陈学明,邓军,白金刚,等 云南白牛厂矿区沉积盆地的成矿流体系统[J].现代地质,2000,14(2):173—178
[2] 杨兵,王之田 铜官山铜矿床新类型矿体的发现及矿床成因模式[J].矿床地质,1985,4(4):41—13
[3] 徐克勤,朱金初 我国东南部几个断裂拗陷带中沉积(或火山沉积)热液叠加类铁铜矿床成因的探讨[J].福建地质,1978,4:1—68
[4] 顾连兴,徐克勤 论长江中下游中石炭世海底块状硫化物矿床[J] 地质学报,1986,60(2):176—188
[5] GuLianxin,HuWenxuan,HeJinxiang,etal Regionalvar iationsinorecompositionandfluidfeaturesofmassivesulphidedepositsinSouthChina:Implicationsforgeneticmodelling[J].Episodes,2000,23(2):110—118
[6] ZhaiYS,XiongYL,YaoSZ,etal MetallogenyofcopperandirondepositsintheeasternYangtzeCraton,east-centralChina[J].OreGeologyReviews,1996,11:229—248
[7] XuG,ZhouJ TheXinqiaoCu-S-Fe-AudepositintheTonglingmineraldistrict,China:synorogenicremobilizationofastratiformsulfidedeposit[J].OreGeologyReviews,2001,18:77—94
[8] StuartFM,TurnerG,DuckworthRC,etal Heliumisotopesastracersoftrappedhydrothermalfluidsinoceanfloorsulfides[J].Geology,1994,22:823—826
[9] BaptistePJ,FouquetY AbundanceandisotopiccompositionofheliuminhydrothermalsulfidesfromtheEastPacificRiseat13°N[J].GeochimCosmochimActa,1996,60:87—93
[10]TrullTW,KurzMD,JenkinsWJ Diffusionofcosmogenic3Heinolivineandquartz:implicationsforsurfaceexposuredating[J].EarthPlanetSciLett,1991,103:241—256
[11]QiuHN 40Ar/39ArdatingofthequartzsamplesfromtwomineraldepositsinwesternYunnan(SWChina)bycrushinginvacuum[J].ChemGeol,1996,127:211—222
[12]TurnerG,StuartF Helium/heatratiosanddepositiontemperaturesofsulfidesfromtheoceanfloor[J].Nature,1992,357:581—583
[13]TurnerG,BurnardPB,FordJL,etal Tracingfluidsourcesandinteraction[J] PhilTransRSocLondA,1993,344:127—140
[14]BurnardPG,HuR,TurnerG,etal Mantle,crustalandatmosphericnoblegasesinAilaoshangolddeposits,YunnanProvince,China[J].GeochimCosmochimActa,1999,63:1595—1604
[15]曾普胜,裴荣富,侯增谦,等 安徽铜陵地块沉积-喷流块状硫化物矿床[J].矿床地质,2002,21(增刊):532—535.
[16]WincklerG,Aeschbach HertigW,KipferR,etal ConstraintsonoriginandevolutionofRedSeabrinesfromheliumandargonisotopes[J].EarthPlanetSciLet,2001,184:671—683
[17]曾志刚,秦蕴珊,翟世奎 大西洋中脊TAG热液区硫化物中流体包裹体的He-Ne-Ar同位素组成[J].中国科学D辑,2000,30(6):628—633
[18]佟景贵,李胜荣,肖启云,等 贵州遵义中南村黑色岩系黄铁矿的成分标型与成因探讨[J].现代地质,2004,18(1):41—47
[19]陈学明,邓军,白金刚,等 云南白牛厂矿区沉积盆地的成矿流体系统[J].现代地质,2000,14(2):173—178
目录