黔东南油麻坳金矿床含金石英脉钨富集机理
|
摘要
黔东南油麻坳金矿床产于下江群清水江组低绿片岩相浅变质岩系中,具有典型造山型金矿特征。与其他造山型金矿一样,含金石英脉中以W为代表的高温亲石元素富集机理尚不清楚。通过岩相学特征分析,应用电感耦合等离子体质谱(ICP-MS),对油麻坳金矿床含金石英脉、近矿围岩及赋矿地层样品的岩石学特征、微量元素和稀土元素系统研究。结果表明,含金石英脉中除Cu、Pb、Zn、As等主要成矿元素外,亲石元素W也相对富集,并以极少数白钨矿单颗粒形式赋存;稀土元素分布特征为轻稀土富集、重稀土亏损的右倾型配分模式,δEu异常不明显,δCe呈弱负异常。R型聚类分析表明,W、Mo等成矿元素与变质作用密切相关的Rb、Sr、Ba、Ta、Zr、Sc、V、Sn等上地壳分散元素和弱矿化元素具有成因联系。综合分析认为,钨富集机理为较低温压条件下,成矿流体携带的W与局部高含量钙质矿物结合,以白钨矿形式赋存于含金石英脉中,随后期变质作用加强,W被化学活动性流体携带进入近矿围岩,当蚀变达千枚岩化时,石英脉体中W几乎全部进入近矿围岩及赋矿地层中。
Host rocks of the Youma 'ao gold deposit in southeastern Guizhou are mainly low greenschist facies metamorphosed rock series in the Neoproterozoic Qingshuijiang Formation of the Xiajiang Group. The Youma'ao gold deposit is a typical orogenic gold deposit. So far,the enrichment mechanism of high-temperature lithophile element of W in gold-bearing quartz veins is unclear. The petrography and inductively coupled plasma mass spectrometry( ICPMS) are used to determine trace elements and REE contents of the gold-bearing quartz veins,wall-rocks and orehosted strata rocks collected from the Youma'ao gold deposit. The results show that the lithophile element W is also relatively enriched besides the enrichment of main ore-forming elements( e. g. Cu,Pb,Zn,and As,etc.) in the gold-bearing quartz veins. There are slightly right-declined REE patterns,with enrichment of LREE,no obvious Eu anomaly,and weakly negative Ce anomaly. The R-type cluster analysis shows that W,Mo of ore-forming elements have close genetic relationship with Rb,Sr,Ba,Ta,Zr,Sc,V,Sn of upper crust disperse elements or weak mineralized elements. Above all,the W enrichment mechanism is believed that the W in the W-bearing fluid was firstly combined with the local high-content calcareous minerals under low temperatures and pressures to have formed the scheelite particles in the quartz-bearing vein. Secondly,with the increase of the metamorphism intensity,the W was reactivated by the chemically active fluid and then gradually transported into the wall-rock. Thirdly,at the stage ofphyllitization,almost all of the W which was activated and removed from the quartz veins was then transported into the wall-rock and ore-bearing strata.
Host rocks of the Youma 'ao gold deposit in southeastern Guizhou are mainly low greenschist facies metamorphosed rock series in the Neoproterozoic Qingshuijiang Formation of the Xiajiang Group. The Youma'ao gold deposit is a typical orogenic gold deposit. So far,the enrichment mechanism of high-temperature lithophile element of W in gold-bearing quartz veins is unclear. The petrography and inductively coupled plasma mass spectrometry( ICPMS) are used to determine trace elements and REE contents of the gold-bearing quartz veins,wall-rocks and orehosted strata rocks collected from the Youma'ao gold deposit. The results show that the lithophile element W is also relatively enriched besides the enrichment of main ore-forming elements( e. g. Cu,Pb,Zn,and As,etc.) in the gold-bearing quartz veins. There are slightly right-declined REE patterns,with enrichment of LREE,no obvious Eu anomaly,and weakly negative Ce anomaly. The R-type cluster analysis shows that W,Mo of ore-forming elements have close genetic relationship with Rb,Sr,Ba,Ta,Zr,Sc,V,Sn of upper crust disperse elements or weak mineralized elements. Above all,the W enrichment mechanism is believed that the W in the W-bearing fluid was firstly combined with the local high-content calcareous minerals under low temperatures and pressures to have formed the scheelite particles in the quartz-bearing vein. Secondly,with the increase of the metamorphism intensity,the W was reactivated by the chemically active fluid and then gradually transported into the wall-rock. Thirdly,at the stage ofphyllitization,almost all of the W which was activated and removed from the quartz veins was then transported into the wall-rock and ore-bearing strata.
引文
[1]Goldfarb R J,Baker T,Dube B,et al.Distribution,character and genesis of gold deposits in metamorphic terranes[A].Hedenquist J F H,Thompson R J,Goldfarb J P,et al.Economic Geology One Hundredth Anniversary Volume[M].Colorado:Society of Economic Geologists,2005:40.
[2]Groves D I,Goldfarb R J,Gebre-Mariam M,et al.Orogenic gold deposits:a proposed classification in the context of their crustal distribution and relationship to other gold deposit types[J].Ore Geology Reviews,1998,13(1-5):7-27.
[3]Kerrich R,Goldfarb R J,Groves D,et al.The characteristics,origins,and geodynamic settings of supergiant gold metallogenic provinces[J].Science in China Series D:Earth Sciences,2000,43(S1):1-68.
[4]Henley R W,Norris R J,Paterson C J.Multistage ore genesis in the New Zealand geosyncline a history of post-metamorphic lode emplacement[J].Mineralium Deposita,1976,11(2):180-196.
[5]Pitcairn I K,Teagle D A H,Craw D,et al.Sources of metals and fluids in orogenic gold deposits:insights from the Otago and Alpine Schists,New Zealand[J].Economic Geology,2006,101(8):1525-1546.
[6]Cave B J,Stepanov A S,Craw D,et al.Release of trace elements through the sub-greenschist facies breakdown of detrital rutile to metamorphic titanite in the Otago Schist,New Zealand[J].The Canadian Mineralogist,2015,53(3):379-400.
[7]Cave B J,Pitcairn I K,Craw D,et al.A metamorphic mineral source for tungsten in the turbidite-hosted orogenic gold deposits of the Otago Schist,New Zealand[J].Mineralium Deposita,2017,52(4):515-537.
[8]Goldfarb R J,Groves D I.Orogenic gold:common or evolving fluid and metal sources through time[J].Lithos,2015,233:2
[9]张杰,余大龙,李明琴,等.贵州天柱磨山—油麻坳金矿化带地球化学特征及成矿作用[J].矿物岩石地球化学通报,1997,16(3):186-190.
[10]卢焕章,王中刚,吴学益,等.贵州东南部的地质构造与金矿床的关系[J].地质学报,2005,79(1):98-105.
[11]陶平,王尚彦,戴传固,等.黔东地区金矿床类型及其基本特征[J].贵州地质,2005,22(4):229-235.
[12]吴学益,卢焕章,吕古贤,等.黔东南锦屏-天柱地区构造控岩控金特征模拟实验及其力学分析[J].大地构造与成矿学,2006,30(3):355-368.
[13]杨光忠.黔东南地区热液型金矿的成矿作用及其模式[J].贵州地质,2006,23(3):197-202.
[14]杨瑞东,张晓东,刘玲,等.贵州锦屏新元古界青白口系下江群稀土、微量元素分布特征——探讨金的来源问题[J].地质学报,2009,83(4):505-514
[15]杜定全,刘志臣,孙士军,等.黔东南地区金矿控矿构造的空间关系分析[J].矿物岩石地球化学通报,2010,29(4):380-387.
[16]王甘露,赵万飞,苏杭,等.黔东南与黔西南浊积岩中两种不同类型金矿的比较[J].世界地质,2014,33(3):572-580.
[17]张传昱,邢程,陈曹军.黔东南地区金矿床成矿模式及找矿远景[J].地质与勘探,2015,51(4):690-698.
[18]王尚彦,陶平,代传固,等.贵州东部金矿[M].北京:地质出版社,2006:1-177.
[19]王加昇,温汉捷,李超,等.黔东南石英脉型金矿毒砂ReOs同位素定年及其地质意义[J].地质学报,2011,85(6):955-964.
[20]顾尚义,杜定全,付勇,等.江南造山带西南缘石英脉型金矿中毒砂Re-Os同位素定年研究[J].岩矿测试,2016,35(5):542-549.
[21]朱笑青,王甘露,卢焕章,等.黔东南金矿形成时代的确定兼论湘黔加里东金矿带[J].中国地质,2006,33(5):1092-1099.
[22]张杰,余大龙,张先煜,等.贵州天柱磨山—油麻坳金矿化带岩石矿物地球化学研究[J].地质与勘探,1998,34(2):30-36.
[23]Liang Q,Jing H,Gregoire D C.Determination of trace elements in granites by inductively coupled plasma mass spectrometry[J].Talanta,2000,51(3):507-513.
[24]Grigor’yeva T,Sukneva L.Effects of sulphur and of antimony and arsenic sulphides on the solubility of gold[J].Geokhimiya,1981,10:1534-1540.
[25]Rudnick R L,Gao S.Composition of the continental crust[A].Holland H D,Turekian K K.Treatise on Geochemistry[M].Oxford:Elsevier-Pergamon,2003:1-64.
[26]刘英俊,马东升.钨的地球化学[M].北京:科学出版社,1987.
[27]张晓东,杨瑞东,刘玲,等.贵州锦屏新元古界下江群元素地球化学特征及其与金矿的关系[J].地质学报,2012,86(2):258-268.
[28]Herrmann A G.Yttrium and lanthanides[A].Wedepohl K H.Handbook of Geochemistry[M].Berlin:Springer,1970:57-71.
[29]Boynton W V.Cosmochemistry of the rare earth elements:meteorite studies[J].Developments in Geochemistry,1984,2:63-114.
[2]Groves D I,Goldfarb R J,Gebre-Mariam M,et al.Orogenic gold deposits:a proposed classification in the context of their crustal distribution and relationship to other gold deposit types[J].Ore Geology Reviews,1998,13(1-5):7-27.
[3]Kerrich R,Goldfarb R J,Groves D,et al.The characteristics,origins,and geodynamic settings of supergiant gold metallogenic provinces[J].Science in China Series D:Earth Sciences,2000,43(S1):1-68.
[4]Henley R W,Norris R J,Paterson C J.Multistage ore genesis in the New Zealand geosyncline a history of post-metamorphic lode emplacement[J].Mineralium Deposita,1976,11(2):180-196.
[5]Pitcairn I K,Teagle D A H,Craw D,et al.Sources of metals and fluids in orogenic gold deposits:insights from the Otago and Alpine Schists,New Zealand[J].Economic Geology,2006,101(8):1525-1546.
[6]Cave B J,Stepanov A S,Craw D,et al.Release of trace elements through the sub-greenschist facies breakdown of detrital rutile to metamorphic titanite in the Otago Schist,New Zealand[J].The Canadian Mineralogist,2015,53(3):379-400.
[7]Cave B J,Pitcairn I K,Craw D,et al.A metamorphic mineral source for tungsten in the turbidite-hosted orogenic gold deposits of the Otago Schist,New Zealand[J].Mineralium Deposita,2017,52(4):515-537.
[8]Goldfarb R J,Groves D I.Orogenic gold:common or evolving fluid and metal sources through time[J].Lithos,2015,233:2
[9]张杰,余大龙,李明琴,等.贵州天柱磨山—油麻坳金矿化带地球化学特征及成矿作用[J].矿物岩石地球化学通报,1997,16(3):186-190.
[10]卢焕章,王中刚,吴学益,等.贵州东南部的地质构造与金矿床的关系[J].地质学报,2005,79(1):98-105.
[11]陶平,王尚彦,戴传固,等.黔东地区金矿床类型及其基本特征[J].贵州地质,2005,22(4):229-235.
[12]吴学益,卢焕章,吕古贤,等.黔东南锦屏-天柱地区构造控岩控金特征模拟实验及其力学分析[J].大地构造与成矿学,2006,30(3):355-368.
[13]杨光忠.黔东南地区热液型金矿的成矿作用及其模式[J].贵州地质,2006,23(3):197-202.
[14]杨瑞东,张晓东,刘玲,等.贵州锦屏新元古界青白口系下江群稀土、微量元素分布特征——探讨金的来源问题[J].地质学报,2009,83(4):505-514
[15]杜定全,刘志臣,孙士军,等.黔东南地区金矿控矿构造的空间关系分析[J].矿物岩石地球化学通报,2010,29(4):380-387.
[16]王甘露,赵万飞,苏杭,等.黔东南与黔西南浊积岩中两种不同类型金矿的比较[J].世界地质,2014,33(3):572-580.
[17]张传昱,邢程,陈曹军.黔东南地区金矿床成矿模式及找矿远景[J].地质与勘探,2015,51(4):690-698.
[18]王尚彦,陶平,代传固,等.贵州东部金矿[M].北京:地质出版社,2006:1-177.
[19]王加昇,温汉捷,李超,等.黔东南石英脉型金矿毒砂ReOs同位素定年及其地质意义[J].地质学报,2011,85(6):955-964.
[20]顾尚义,杜定全,付勇,等.江南造山带西南缘石英脉型金矿中毒砂Re-Os同位素定年研究[J].岩矿测试,2016,35(5):542-549.
[21]朱笑青,王甘露,卢焕章,等.黔东南金矿形成时代的确定兼论湘黔加里东金矿带[J].中国地质,2006,33(5):1092-1099.
[22]张杰,余大龙,张先煜,等.贵州天柱磨山—油麻坳金矿化带岩石矿物地球化学研究[J].地质与勘探,1998,34(2):30-36.
[23]Liang Q,Jing H,Gregoire D C.Determination of trace elements in granites by inductively coupled plasma mass spectrometry[J].Talanta,2000,51(3):507-513.
[24]Grigor’yeva T,Sukneva L.Effects of sulphur and of antimony and arsenic sulphides on the solubility of gold[J].Geokhimiya,1981,10:1534-1540.
[25]Rudnick R L,Gao S.Composition of the continental crust[A].Holland H D,Turekian K K.Treatise on Geochemistry[M].Oxford:Elsevier-Pergamon,2003:1-64.
[26]刘英俊,马东升.钨的地球化学[M].北京:科学出版社,1987.
[27]张晓东,杨瑞东,刘玲,等.贵州锦屏新元古界下江群元素地球化学特征及其与金矿的关系[J].地质学报,2012,86(2):258-268.
[28]Herrmann A G.Yttrium and lanthanides[A].Wedepohl K H.Handbook of Geochemistry[M].Berlin:Springer,1970:57-71.
[29]Boynton W V.Cosmochemistry of the rare earth elements:meteorite studies[J].Developments in Geochemistry,1984,2:63-114.