陕南勉略阳地区陈家坝铜铅锌多金属矿床稀土元素地球化学特征
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摘要
陕西省陈家坝铜铅锌多金属矿床是勉(县)—略(阳)—阳(平关)三角地区新发现的铜铅锌多金属矿床,通过对矿石及矿区地质体的微量与稀土元素地球化学对比分析,对陈家坝铜铅锌多金属矿床进行了成矿流体特征与成矿机制研究。研究表明,矿石富集LREE、Th/La、Nb/La、Hf/Sm值均小于1,指示成矿流体以富Cl为主。矿石的稀土元素配分曲线、微量元素蛛网图及含量类似于赋矿层位硅化白云岩,推断矿石为同生沉积成矿。矿石显示Ce负异常及Eu正异常,与海底高温热液及其沉积物的稀土元素组成和变化特征相似,反映了矿石与海底热流体及其沉积物形成过程相似,说明该区矿石形成于还原环境,成矿过程中岩浆流体、热卤水与海水组成的混合流体使其更有利于成矿。因此,认为成矿流体具有岩浆流体混合热卤水与海水的特征,流体之间的混合作用与水-岩作用是导致铜铅锌等成矿元素富集、沉淀的重要机制。
The Chenjiaba deposit is a new Cu-Pb-Zn polymetallic deposit discovered in MianxianLueyang-Yang Pingguan triangle area,Shaanxi Province.Based on the geochemical comparison between trace elements and rare earth elements in ore and geological bodies,the ore-forming fluid characteristics and metallogenic mechanism of this deposit have been studied.The result showsthat the ore in this deposit is rich in LREE,the Th/La,Nb/La and Hf/Sm ratios are all less than1,respectively,indicting the geochemical feature of ore-forming fluid mainly enriched in Cl element.The ore has similar REE distribution curve,trace element cobweb diagram and element content with the silicified dolomite in ore-bearing horizon,suggesting that the ore formed by syngenetic sedimentary mineralization.The ore has negative Ce anomalies and positive Eu anomalies,which is similar to those of seafloor hydrothermal fluids and their sediments,indicating that the ore formed in a reducing environment.In the process of mineralization,the mixture of magmatic fluid,hot brine and sea water makes it more favorable for mineralization.Therefore,it is considered that the ore-forming fluid has the geochemical characteristics of the magmatic fluid mixed with hot brine and seawater.The fluid mixing action and the water rock interaction are important mechanisms for the enrichment and precipitation of Cu,Pb and Zn ore-forming elements.
The Chenjiaba deposit is a new Cu-Pb-Zn polymetallic deposit discovered in MianxianLueyang-Yang Pingguan triangle area,Shaanxi Province.Based on the geochemical comparison between trace elements and rare earth elements in ore and geological bodies,the ore-forming fluid characteristics and metallogenic mechanism of this deposit have been studied.The result showsthat the ore in this deposit is rich in LREE,the Th/La,Nb/La and Hf/Sm ratios are all less than1,respectively,indicting the geochemical feature of ore-forming fluid mainly enriched in Cl element.The ore has similar REE distribution curve,trace element cobweb diagram and element content with the silicified dolomite in ore-bearing horizon,suggesting that the ore formed by syngenetic sedimentary mineralization.The ore has negative Ce anomalies and positive Eu anomalies,which is similar to those of seafloor hydrothermal fluids and their sediments,indicating that the ore formed in a reducing environment.In the process of mineralization,the mixture of magmatic fluid,hot brine and sea water makes it more favorable for mineralization.Therefore,it is considered that the ore-forming fluid has the geochemical characteristics of the magmatic fluid mixed with hot brine and seawater.The fluid mixing action and the water rock interaction are important mechanisms for the enrichment and precipitation of Cu,Pb and Zn ore-forming elements.
引文
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高仁祥,陈琛,吴尊,等.磷酸法测定碳、氧同位素[J].石油实验地质,1984,6(1):72-75.GAO Renxiang,CHEN Chen,WU Chun,et al.Determination of carbon and oxygen isotopesby phosphoric acid method[J].Petroleum Experimental Geology,1984,6(1):72-75.
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毛景文,谢桂青,张作衡,等.中国北方中生代大规模成矿作用的期次及其地球动力学背景[J].岩石学报,2005,21(1):169-188.MAO Jingwen,XIE Guiqing,ZHANG Zuoheng,et al.The Mesozoic large-scale metallogenesis in northern China and its geodynamic background[J].Acta Petrota Sinica,2005,21(1):169-188.
王瑞廷,王东生,代军治,等.秦岭造山带陕西段主要矿集区铅锌银铜金矿综合勘查技术研究[M].北京:地质出版社,2012:1-275.WANG Ruiting,WANG Dongsheng,DAI Junzhi,et al.The comprehensive exploration technology of lead zinc silver copper gold deposit in the main ore concentration area of Shaanxi section ofQinling Mountains orogenic belt[M].Beijing:Geological Publishing House,2012:1-275.
叶霖,刘铁庚.陕南勉宁略地区铜厂铜矿包裹体地球化学特征研究[J].矿物学报,1997,17(2):194-199.YE Lin,LIU Tiegeng.Study on the geochemical characteristics of the inclusions in copper ore deposits in the Mian Ninglu region,southern Shaanxi[J].Journal of Minerals,1997,17(2):194-199.
叶霖,刘铁庚,王兴理.陕南勉宁略地区铜厂铜矿找矿标志探讨[J].矿物学报,1999,19(1):103-107.YE Lin,LIU Tiegeng,WANG Xingli.Exploration of copper ore prospecting markers in the copper factory,Mian Ninglu region,southern Shaanxi[J].Mineral Journal,1999,19(1):103-107.
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于海涛,孟庆海,郭骞.河南嵩山石秤岩体稀土元素特征及矿源研究[J].西北地质,2016,49(1):34-38.YU Haitao,MENG Qinghai,GUO Qian.Study on the characteristics of rare earth elements and ore sources of Songshan stone scale rock mass in Henan[J].Northwest Geology,2016,49(1):34-38.
周圣华.陕西铜厂铜金多金属矿床地质特征及成矿流体地球化学[J].中国地质,2008,35(2):298-304.ZHOU Shenghua.The geological characteristics and metallogenic fluid geochemistry of the copper gold polymetallic deposit in the Shaanxi copper plant[J].China Geology,2008,35(2):298-304.
张理刚.稳定同位素在地质科学中的应用:金属活化热液成矿作用及找矿[M].西安:陕西科学技术出版社,1985,1-246.ZHANG Ligang.Application of stable isotopes in Geological Science:metal activated hydrothermal mineralization and prospecting[M].Xi'an:Shaanxi Science and Technology Press,1985,1-246.
BAU M.Rare-earth element mobility during hydrothermal and metamorphic fluid-rock interaction and the significance of the oxidation state ofeuropium[J].Chemical Geology,1991,93(3-4):219-230.
G.P KLINKHAMMER,ELDERFIELD H,EDMOND JM,et al.Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-oceanridges[J].Geochimica et Cosmochimica Acta,1994,58(23):5105-5113.
KEPPLER H.Constraints from partitioning experiments on the composition of subduction-zone fluids[J].Nature,1996,380(6571):237-240.
RACHEL A.Mills,ELDERFIELD H.Rare earth element geochemistry of hydrothermal deposits from the active TAG Mound,26N Mid-Atlantic Ridge[J].Geochimicaet Cosmochimica Acta,1995,59(17):3511-3524.
SHIKAZONO N,OGAWA Y,UTADA M,et al.Geochemical behavior of rare earth elements in hydrothermally altered rocks of the Kuroko mining area,Japan[J].J Geochem Expl,2008,98:65-79.
SHIKAZONO N.Rare earth element geochemistry of Kuroko ores and hydrothermal altered rocks:Implication for evolution of submarine hydrothermal system at back arc basin[J].Res Geol Spec Issue,1999,No.20:23-30.
SUN SS,MCDONOUGH WF.Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J].Geological Society,London,Special Publications,1989,42(1):313-345.
陈广庭.陕西略阳陈家坝古火山机构的探讨[J].陕西理工学院学报:自然科学版,1997,(4):14-19.CHEN Guangting.A discussion on the ancient volcano mechanism of Chen Jiaba,Lueyang,Shaanxi[J].Journal of Shaanxi University of Technology:Natural Science Edition,1997,(4):14-19.
丁振举,姚书振,周宗桂,等.陕西略阳铜厂铜矿成矿时代及地质意义[J].地球科学与环境学报,1998,20(3):18-29.DING Zhenju,YAO Shuzhen,ZHOU Zonggui,et al.The metallogenic epoch and geological significance of copper ore in Lueyang,Shaanxi[J].Shaanxi Journal of Geoscience and Environment,1998,20(3):18-29.
丁振举,刘丛强,姚书振,等.东沟坝多金属矿床矿质来源的稀土元素地球化学限制[J].吉林大学学报(地球科学版),2003,33(4):437-442.DING Zhenju,LIU Congqiang,YAO Shuzhen,et al.Geochemistry of rare earth elements limit mineral sources of the Donggouba polymetallic deposit[J].Journal of Jilin University(Earth Science Edition),2003,33(4):437-442.
丁坤,王瑞廷,钱壮志,等.陕西省陈家坝铜铅锌多金属矿床地质地球化学特征及矿床成因探讨[J].地质与勘探,2017,53(3):436-444.DING Kun,WANG Ruiting,QIAN Zhuangzhi,et al.Geological and geochemical characteristics and ore genesis of the Chen Jiaba polymetallic deposit,Shaanxi Province[J].Geology and Exploration,2017,53(3):436-444.
丁坤.陕西省勉略阳地区陈家坝铜铅锌多金属矿床地质特征及矿床成因探讨[D].西安:长安大学,2017,1-58.DING Kun.Geological characteristics and genesis of the Chenjiaba CU-Pb-Zn polymetallic deposit in the Lueyang area of ShaanxiProvince[D].Xi'an:Chang'an University,2017,1-58.
代军治,陈荔湘,王瑞廷,等.陕西省略阳县徐家沟铜矿床地质地球化学特征及成矿模式[J].西北地质,2016,49(4):99-109.DAI Junzhi,CHEN Lixiang,WANG Ruiting,et al.Geological and geochemical characteristics and metallogenic model of the Xujiagou copper deposit in Lueyang County,Shaanxi province[J].Northwest Geology,2016,49(4):99-109.
丁振举,姚书振,刘丛强,等.东沟坝多金属矿床喷流沉积成矿特征的稀土元素地球化学示踪[J].岩石学报,2003,19(4):792-798.DING Zhenju,YAO Shuzhen,LIU Congqiang,et al.Donggouba polymetallic deposit exhalative sedimentary metallogenic characteristics of the REE geochemical tracer[J].Acta Petrologica Sinica,2003,19(4):792-798.
富公勤,石林,李世麟.陕西省陈家坝变质火山体系[J].矿物岩石,1996,16(3):1-16.FU Gongqin,SHI Lin,LI Shilin.The Mineral rocks of the Chen Jiaba metamorphic volcano system in Shaanxi Province[J].Journal of Mineralogy and Petrology,1996,16(3):1-16.
韩润生,刘丛强,马德云,等.铜石矿田陈家坝地区断裂构造地球化学特征及定位预测[J].地质与勘探,2000,36(5):66-69.HAN Runsheng,LIU Congqiang,MA Deyun,et al.Geochemical characteristics and location prediction of the fracture structure in the Chen Jiaba area,Tongshi[J].Geology and Exploration,2000,36(5):66-69.
韩吟文,马振东,张宏飞.地球化学[M].北京:地质出版社,2003:1-370.HAN Yinwen,MA Zhendong,ZHANG Hongfei.Geochemistry[M].Beijing:Geological Publishing House,2003:1-370.
高仁祥,陈琛,吴尊,等.磷酸法测定碳、氧同位素[J].石油实验地质,1984,6(1):72-75.GAO Renxiang,CHEN Chen,WU Chun,et al.Determination of carbon and oxygen isotopesby phosphoric acid method[J].Petroleum Experimental Geology,1984,6(1):72-75.
李福让,王瑞廷,高晓宏,等.陕西省略阳县徐家沟铜矿床成矿地质特征及控矿因素[J].地质学报,2009,83(11):1752-1761.LI Furang,WANG Ruiting,GAO Xiaohong,et al.The geological characteristics and ore controlling factors of Xujiagou copper deposit in Lueyang County,Shaanxi province[J].Acta Geology Sinica,2009,83(11):1752-1761.
毛景文,谢桂青,张作衡,等.中国北方中生代大规模成矿作用的期次及其地球动力学背景[J].岩石学报,2005,21(1):169-188.MAO Jingwen,XIE Guiqing,ZHANG Zuoheng,et al.The Mesozoic large-scale metallogenesis in northern China and its geodynamic background[J].Acta Petrota Sinica,2005,21(1):169-188.
王瑞廷,王东生,代军治,等.秦岭造山带陕西段主要矿集区铅锌银铜金矿综合勘查技术研究[M].北京:地质出版社,2012:1-275.WANG Ruiting,WANG Dongsheng,DAI Junzhi,et al.The comprehensive exploration technology of lead zinc silver copper gold deposit in the main ore concentration area of Shaanxi section ofQinling Mountains orogenic belt[M].Beijing:Geological Publishing House,2012:1-275.
叶霖,刘铁庚.陕南勉宁略地区铜厂铜矿包裹体地球化学特征研究[J].矿物学报,1997,17(2):194-199.YE Lin,LIU Tiegeng.Study on the geochemical characteristics of the inclusions in copper ore deposits in the Mian Ninglu region,southern Shaanxi[J].Journal of Minerals,1997,17(2):194-199.
叶霖,刘铁庚,王兴理.陕南勉宁略地区铜厂铜矿找矿标志探讨[J].矿物学报,1999,19(1):103-107.YE Lin,LIU Tiegeng,WANG Xingli.Exploration of copper ore prospecting markers in the copper factory,Mian Ninglu region,southern Shaanxi[J].Mineral Journal,1999,19(1):103-107.
燕长海,徐勇航,彭翼,等.东秦岭二郎坪群火山岩中火山成因块状硫化物矿床地质地球化学特征及其成因讨论[J].矿床地质,2008,27(1):14-27.YAN Changhai,XU Yonghang,PENG Yi,et al.Geological and geochemical characteristics and genesis of volcanic hosted massive sulfide deposits in volcanic rocks of Erlang Ping group in eastern QinlingMountains[J].Ore Geology,2008,27(1):14-27.
于海涛,孟庆海,郭骞.河南嵩山石秤岩体稀土元素特征及矿源研究[J].西北地质,2016,49(1):34-38.YU Haitao,MENG Qinghai,GUO Qian.Study on the characteristics of rare earth elements and ore sources of Songshan stone scale rock mass in Henan[J].Northwest Geology,2016,49(1):34-38.
周圣华.陕西铜厂铜金多金属矿床地质特征及成矿流体地球化学[J].中国地质,2008,35(2):298-304.ZHOU Shenghua.The geological characteristics and metallogenic fluid geochemistry of the copper gold polymetallic deposit in the Shaanxi copper plant[J].China Geology,2008,35(2):298-304.
张理刚.稳定同位素在地质科学中的应用:金属活化热液成矿作用及找矿[M].西安:陕西科学技术出版社,1985,1-246.ZHANG Ligang.Application of stable isotopes in Geological Science:metal activated hydrothermal mineralization and prospecting[M].Xi'an:Shaanxi Science and Technology Press,1985,1-246.
BAU M.Rare-earth element mobility during hydrothermal and metamorphic fluid-rock interaction and the significance of the oxidation state ofeuropium[J].Chemical Geology,1991,93(3-4):219-230.
G.P KLINKHAMMER,ELDERFIELD H,EDMOND JM,et al.Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-oceanridges[J].Geochimica et Cosmochimica Acta,1994,58(23):5105-5113.
KEPPLER H.Constraints from partitioning experiments on the composition of subduction-zone fluids[J].Nature,1996,380(6571):237-240.
RACHEL A.Mills,ELDERFIELD H.Rare earth element geochemistry of hydrothermal deposits from the active TAG Mound,26N Mid-Atlantic Ridge[J].Geochimicaet Cosmochimica Acta,1995,59(17):3511-3524.
SHIKAZONO N,OGAWA Y,UTADA M,et al.Geochemical behavior of rare earth elements in hydrothermally altered rocks of the Kuroko mining area,Japan[J].J Geochem Expl,2008,98:65-79.
SHIKAZONO N.Rare earth element geochemistry of Kuroko ores and hydrothermal altered rocks:Implication for evolution of submarine hydrothermal system at back arc basin[J].Res Geol Spec Issue,1999,No.20:23-30.
SUN SS,MCDONOUGH WF.Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J].Geological Society,London,Special Publications,1989,42(1):313-345.