安徽东至兆吉口铅锌矿床的地质和地球化学特征及成因
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摘要
安徽省东至县兆吉口铅锌矿床是近年来在江南过渡带上新发现的一处大型铅锌矿床。矿体受NNE向东至断裂及其次级张扭性裂隙控制。矿石主要呈脉状、细脉-网脉状充填于中元古界蓟县系木坑组浅变质碎屑岩中,亦见矿脉穿切细晶闪长岩脉。矿石的矿物组合主要为闪锌矿+方铅矿+黄铁矿+石英+方解石。矿石结构以交代结构、交代残余结构和填隙结构为主;矿石构造主要为脉状和网脉状,局部块状或团块状。围岩蚀变主要为硅化、黄铁矿化和碳酸盐化。矿床主成矿阶段流体包裹体类型以富液相气液包裹体(V_(H_2O)+L_(H_2O))为主,均一温度为110~275℃,盐度为0.18%~12.85%NaCleq,密度为0.57~1.03 g/cm~3,成矿压力为24.4~61.9 MPa,成矿深度为1.0~2.5 km,显示成矿流体为低温、低密度、中-低盐度的流体;流体包裹体液相成分反映成矿流体为CaSO_4-Na Cl-H_2O体系。矿石中石英δ~(18)O值为12.7‰~15.9‰,换算为成矿流体的δ~(18)OH_2O值为-2.7‰~0.8‰,δD值为-81.5‰~-70.7‰,显示成矿流体为深源岩浆水与大气降水的混合溶液。矿脉中的方解石δ~(13)CV-PDB值为-8.08‰~-7.73‰,δ~(18)OSMOW值为8.49‰~9.44‰,反映成矿的炭质主要来自深部岩浆。综合成矿地质背景、矿床地质和地球化学特征,可以认为,兆吉口铅锌矿床是一个受断裂构造控制的、与燕山期中酸性岩浆作用密切相关的浅成低温热液脉状矿床。
The Zhaojikou lead-zinc deposit is located in the Jiangnan transition belt of Anhui province. The ore-body is controlled by regional structures of the NNE-trending Dongzhi fault and its secondary tensional shear fractures. The occurrence of ores is vein, veinlet, and stockwork in the low metamorphic clastic rocks of the Mukeng Formation of the Mesoproterozoic Jixian Syetem. The ore mineral assemblage includes sphalerite, galena, pyrite, quartz, and calcite. The ore is characterized by metasomatic texture, metasomatic relict and filling texture, vein, stockwork and massive structure. The types of wall-rock alteration are mainly silicification, pyritization, and carbonatization. There are three types of fluid inclusions in the Zhaojikou deposit, mainly the gas-liquid fluid inclusions. Study of the fluid inclusions in quartz in various mineralization stages indicates that the ore fluids belong to low-temperature(110-275 ℃), lowdensity(0.57-1.03 g/cm~3), low- to medium-salinity(0.18%-12.85% NaCleq), the CaSO_4-Na Cl-H_2O hydrochemical type and formed in a low-pressure(24.4-61.9 MPa) and shallow(1.0-2.5 km) environment. The δ18OSMOW values of the quartz in the main mineralization stage change from 12.7‰ to 15.9‰, and the δ~(18)OH_2O values vary between-2.7‰ and 0.8‰, with the δDV-SMOW values ranging from-81.5‰ to-70.7‰, which reflects that the ore-forming fluids was magmatic water with input of meteoric water. The δ~(13)CV-PDB values vary from-8.08‰ to-7.73‰, and the δ~(18)OSMOWvalues ranging from 8.49‰ to 9.44‰ for calcites show that the carbon and oxygen of calcites are sourced mainly from magma. Combined with the geological evidence and analytical results, we conclude that the Zhaojikou lead-zinc deposit is of low temperature epithermal type that is controlled by fault system and related to the Yanshan magma activity.
The Zhaojikou lead-zinc deposit is located in the Jiangnan transition belt of Anhui province. The ore-body is controlled by regional structures of the NNE-trending Dongzhi fault and its secondary tensional shear fractures. The occurrence of ores is vein, veinlet, and stockwork in the low metamorphic clastic rocks of the Mukeng Formation of the Mesoproterozoic Jixian Syetem. The ore mineral assemblage includes sphalerite, galena, pyrite, quartz, and calcite. The ore is characterized by metasomatic texture, metasomatic relict and filling texture, vein, stockwork and massive structure. The types of wall-rock alteration are mainly silicification, pyritization, and carbonatization. There are three types of fluid inclusions in the Zhaojikou deposit, mainly the gas-liquid fluid inclusions. Study of the fluid inclusions in quartz in various mineralization stages indicates that the ore fluids belong to low-temperature(110-275 ℃), lowdensity(0.57-1.03 g/cm~3), low- to medium-salinity(0.18%-12.85% NaCleq), the CaSO_4-Na Cl-H_2O hydrochemical type and formed in a low-pressure(24.4-61.9 MPa) and shallow(1.0-2.5 km) environment. The δ18OSMOW values of the quartz in the main mineralization stage change from 12.7‰ to 15.9‰, and the δ~(18)OH_2O values vary between-2.7‰ and 0.8‰, with the δDV-SMOW values ranging from-81.5‰ to-70.7‰, which reflects that the ore-forming fluids was magmatic water with input of meteoric water. The δ~(13)CV-PDB values vary from-8.08‰ to-7.73‰, and the δ~(18)OSMOWvalues ranging from 8.49‰ to 9.44‰ for calcites show that the carbon and oxygen of calcites are sourced mainly from magma. Combined with the geological evidence and analytical results, we conclude that the Zhaojikou lead-zinc deposit is of low temperature epithermal type that is controlled by fault system and related to the Yanshan magma activity.
引文
艾金彪,马生明,朱立新,樊连杰,胡兆鑫,席明杰.2013.长江中下游马头斑岩型钼铜矿床常量元素、稀土元素特征及迁移规律.地质学报,87(5):691-702.
安徽省核工业勘查技术总院.2011.安徽省东至县兆吉口铅锌多金属矿床成矿规律研究报告.
曹达旺,陈永明,乐成生.2010.东至县兆吉口铅锌多金属矿成矿地质特征及找矿方向.上海地质,31(增刊):206-209.
查世新,韩忠义.2002.岳山银铅锌矿床地球化学特征.资源调查与环境,23(4):272-280.
常印佛,刘湘培,吴言昌.1991.长江中下游铁铜成矿带.北京:地质出版社:1-379.
段开兵,庄天明,段吉琳.2013.安徽东至兆吉口铅锌多金属矿床地质特征及找矿方向.东华理工大学学报,36(2):143-151.
蒋其胜,余传周,黄伟平.2009.安徽省青阳县高家塝钨矿床地质特征及控矿因素.安徽地质,19(4):251-254.
乐成生,揭祥葵.2012.安徽省东至县兆吉口铅锌矿成矿控制条件分析.科技与企业,4:105-107.
李朝阳.1999.中国低温热液矿床集中分布区的一些地质特点.地学前缘,6(1):163-170.
李文庆,曹静平.2006.黄山岭铅锌钼多金属矿床地质特征、成因及找矿方向探讨.安徽地质,16(3):190-193.
刘斌,沈昆.1999.流体包裹体热力学.北京:地质出版社:1-137.
刘建明,刘家军.1997.滇黔桂金三角区微细侵染型金矿床的盆地流体成因模式.矿物学报,17(4):448-456.
毛景文,张建东,郭春丽.2010.斑岩铜矿-浅成低温热液银铅锌-远接触带热液金矿矿床模型:一个新的矿床模型--以德兴地区为例.地球科学与环境学报,32(1):1-14.
钱兵,袁峰,周涛发,范裕,张乐骏,马良.2010.庐枞盆地岳山银铅锌矿床地质特征及硫同位素地球化学研究.矿床地质,24(增刊):495-496.
秦燕,王登红,吴礼彬,王克友,梅玉萍.2010.安徽东源钨矿含矿斑岩中的锆石SHRIMP U-Pb年龄及其地质意义.地质学报,84(4):479-484.
秦臻,戴雪灵,邓湘伟.2012.东秦岭秋树湾铜钼矿流体包裹体和稳定同位素特征及其地质意义.矿床地质,31(2):323-336.
邱瑞龙.1994.贵池黄山岭层控矽卡岩及铅锌矿床成因.安徽地质,4(3):10-18.
邵洁涟.1988.金矿找矿矿物学.北京:中国地质大学出版社:147-205.
宋国学,秦克章,李光明.2010.长江中下游池州地区矽卡岩-斑岩型W-Mo矿床流体包裹体与H、O、S同位素研究.岩石学报,26(9):2768-2782.
唐永成,吴言昌,储国正,邢凤鸣,王永敏,曹奋扬,常印佛.1998.安徽沿江地区铜金多金属矿床地质.北京:地质出版社:1-351.
王克友.2008.青阳县百丈岩钨钼矿床中斑岩型(浸染状)钼矿体的发现及其找矿意义.安徽地质,18(3):185-188.
徐晓春,刘雪,张赞赞,何苗,刘晓燕,谢巧勤,范子良,何俊.2014.安徽东至兆吉口铅锌矿区岩浆岩锆石U-Pb年龄及其地质意义.地质科学,49(2):431-455.
张德会.1992.矿物包裹体液相成分特征及其矿床成因意义.地球科学--中国地质大学学报,17(6):677-688.
张理刚.1989.成岩成矿理论与找矿.北京:北京工业大学出版社:1-200.
张鹏,袁晓玲,张青,阳珊.2011.安徽省青阳县高家塝钨、钼矿床矿石物质组成及其赋存状态.安徽地质,21(3):35-39.
赵文广,孙乘云,狄勤松,蔡晓兵.2007.安徽省青阳县百丈岩钨钼矿床地质特征、成因及找矿方向分析.安徽地质,17(2):90-94,104.
郑永飞,陈江峰.2000.稳定同位素地球化学.北京:科学出版社:1-312.
Clayton R N and Mayeda T K.1963.The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis.Geochimica et Cosmochimica Acta,27(1):43-52.
Clayton R N,O’Neil J R and Mayeda T K.1972.Oxygen isotope exchange between quartz and water.Journal of Geophysical Research,77(17):3057-3067.
Faure G.1986.Principles of Isotope Geology(2rd editon).New York:Wiley:1-589.
Friedman I and O’Neil J R.1977.Compilation of stable isotope fractionation fraction factors of geochemical interest//Fleischer M.Data of Geochemistry(Sixth Edition).Geology Survey Professional Paper:117.
Hall D L,Sterner S M and Bodnar R J.1988.Freezing point depression of Na Cl-KCl-H2O solutions.Economic Geology,83:197-202.
Hoefs J.1997.Stable Isotope Geochemistry.3rd Edition.Berlin:Springer-Verlag:1-201.
Keller J and Hoefs J.1995.Stable isotope characteristics of recent natrocarbonatite from Oldoinyo Lengai//Bell Kand Keller J.Carbonatite Volcanism:Oldoinyo Lengai and the Petrogenesis of Natrocarbonatites.IAVCEIProceedings in Volcanology:113-123.
Mc Crea J M.1950.On the isotope chemistry of carbonates and a paleotemperature scale.Journal of Chemical Physics,18:849-857.
Ohmoto H and Rye R O.1972.Isotopes of sulfur and carbon//Barnes H L.Geochemistry of Hydrothermal Ore Ddeposits.New York:Wiley-Inter Science:509-567.
Ohmoto H and Rye R O.1979.Isotopes of sulfur and carbon//Geochemistry of Hydrothermal Ore Deposits.Economic Geology,67:551-579.
Roedder E.1979.In Physics and Chemistry of the Earth(Volumes 13-14).Oxford:Pergamas Press:9-35.
Schidlowski M.1998.Beginning of terrestrial life:Problems of the early record and implications for extraterrestrial scenarios//Instruments,Methods,and Missions for Astrobiology,SPIE,3441:149-157.
Taylor B M.1986.Magmatic volatiles:Isotope variation of C,H,S//Stable Isotopes in High Temperature Geological Process.Mineralogical Society of America,16:185-226.
Taylor H P.1974.The application of oxygen and hydrogen isotope studies to problems of hydrothermal alteration and ore deposition.Economic Geology,69(6):843-883.
Veizer J I,Holser W T and Wilgus C K.1980.Correlation of13C/12C and 34S/32S secular variation.Geochimica et Cosmochimica Acta,44:579-588.
安徽省核工业勘查技术总院.2011.安徽省东至县兆吉口铅锌多金属矿床成矿规律研究报告.
曹达旺,陈永明,乐成生.2010.东至县兆吉口铅锌多金属矿成矿地质特征及找矿方向.上海地质,31(增刊):206-209.
查世新,韩忠义.2002.岳山银铅锌矿床地球化学特征.资源调查与环境,23(4):272-280.
常印佛,刘湘培,吴言昌.1991.长江中下游铁铜成矿带.北京:地质出版社:1-379.
段开兵,庄天明,段吉琳.2013.安徽东至兆吉口铅锌多金属矿床地质特征及找矿方向.东华理工大学学报,36(2):143-151.
蒋其胜,余传周,黄伟平.2009.安徽省青阳县高家塝钨矿床地质特征及控矿因素.安徽地质,19(4):251-254.
乐成生,揭祥葵.2012.安徽省东至县兆吉口铅锌矿成矿控制条件分析.科技与企业,4:105-107.
李朝阳.1999.中国低温热液矿床集中分布区的一些地质特点.地学前缘,6(1):163-170.
李文庆,曹静平.2006.黄山岭铅锌钼多金属矿床地质特征、成因及找矿方向探讨.安徽地质,16(3):190-193.
刘斌,沈昆.1999.流体包裹体热力学.北京:地质出版社:1-137.
刘建明,刘家军.1997.滇黔桂金三角区微细侵染型金矿床的盆地流体成因模式.矿物学报,17(4):448-456.
毛景文,张建东,郭春丽.2010.斑岩铜矿-浅成低温热液银铅锌-远接触带热液金矿矿床模型:一个新的矿床模型--以德兴地区为例.地球科学与环境学报,32(1):1-14.
钱兵,袁峰,周涛发,范裕,张乐骏,马良.2010.庐枞盆地岳山银铅锌矿床地质特征及硫同位素地球化学研究.矿床地质,24(增刊):495-496.
秦燕,王登红,吴礼彬,王克友,梅玉萍.2010.安徽东源钨矿含矿斑岩中的锆石SHRIMP U-Pb年龄及其地质意义.地质学报,84(4):479-484.
秦臻,戴雪灵,邓湘伟.2012.东秦岭秋树湾铜钼矿流体包裹体和稳定同位素特征及其地质意义.矿床地质,31(2):323-336.
邱瑞龙.1994.贵池黄山岭层控矽卡岩及铅锌矿床成因.安徽地质,4(3):10-18.
邵洁涟.1988.金矿找矿矿物学.北京:中国地质大学出版社:147-205.
宋国学,秦克章,李光明.2010.长江中下游池州地区矽卡岩-斑岩型W-Mo矿床流体包裹体与H、O、S同位素研究.岩石学报,26(9):2768-2782.
唐永成,吴言昌,储国正,邢凤鸣,王永敏,曹奋扬,常印佛.1998.安徽沿江地区铜金多金属矿床地质.北京:地质出版社:1-351.
王克友.2008.青阳县百丈岩钨钼矿床中斑岩型(浸染状)钼矿体的发现及其找矿意义.安徽地质,18(3):185-188.
徐晓春,刘雪,张赞赞,何苗,刘晓燕,谢巧勤,范子良,何俊.2014.安徽东至兆吉口铅锌矿区岩浆岩锆石U-Pb年龄及其地质意义.地质科学,49(2):431-455.
张德会.1992.矿物包裹体液相成分特征及其矿床成因意义.地球科学--中国地质大学学报,17(6):677-688.
张理刚.1989.成岩成矿理论与找矿.北京:北京工业大学出版社:1-200.
张鹏,袁晓玲,张青,阳珊.2011.安徽省青阳县高家塝钨、钼矿床矿石物质组成及其赋存状态.安徽地质,21(3):35-39.
赵文广,孙乘云,狄勤松,蔡晓兵.2007.安徽省青阳县百丈岩钨钼矿床地质特征、成因及找矿方向分析.安徽地质,17(2):90-94,104.
郑永飞,陈江峰.2000.稳定同位素地球化学.北京:科学出版社:1-312.
Clayton R N and Mayeda T K.1963.The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis.Geochimica et Cosmochimica Acta,27(1):43-52.
Clayton R N,O’Neil J R and Mayeda T K.1972.Oxygen isotope exchange between quartz and water.Journal of Geophysical Research,77(17):3057-3067.
Faure G.1986.Principles of Isotope Geology(2rd editon).New York:Wiley:1-589.
Friedman I and O’Neil J R.1977.Compilation of stable isotope fractionation fraction factors of geochemical interest//Fleischer M.Data of Geochemistry(Sixth Edition).Geology Survey Professional Paper:117.
Hall D L,Sterner S M and Bodnar R J.1988.Freezing point depression of Na Cl-KCl-H2O solutions.Economic Geology,83:197-202.
Hoefs J.1997.Stable Isotope Geochemistry.3rd Edition.Berlin:Springer-Verlag:1-201.
Keller J and Hoefs J.1995.Stable isotope characteristics of recent natrocarbonatite from Oldoinyo Lengai//Bell Kand Keller J.Carbonatite Volcanism:Oldoinyo Lengai and the Petrogenesis of Natrocarbonatites.IAVCEIProceedings in Volcanology:113-123.
Mc Crea J M.1950.On the isotope chemistry of carbonates and a paleotemperature scale.Journal of Chemical Physics,18:849-857.
Ohmoto H and Rye R O.1972.Isotopes of sulfur and carbon//Barnes H L.Geochemistry of Hydrothermal Ore Ddeposits.New York:Wiley-Inter Science:509-567.
Ohmoto H and Rye R O.1979.Isotopes of sulfur and carbon//Geochemistry of Hydrothermal Ore Deposits.Economic Geology,67:551-579.
Roedder E.1979.In Physics and Chemistry of the Earth(Volumes 13-14).Oxford:Pergamas Press:9-35.
Schidlowski M.1998.Beginning of terrestrial life:Problems of the early record and implications for extraterrestrial scenarios//Instruments,Methods,and Missions for Astrobiology,SPIE,3441:149-157.
Taylor B M.1986.Magmatic volatiles:Isotope variation of C,H,S//Stable Isotopes in High Temperature Geological Process.Mineralogical Society of America,16:185-226.
Taylor H P.1974.The application of oxygen and hydrogen isotope studies to problems of hydrothermal alteration and ore deposition.Economic Geology,69(6):843-883.
Veizer J I,Holser W T and Wilgus C K.1980.Correlation of13C/12C and 34S/32S secular variation.Geochimica et Cosmochimica Acta,44:579-588.
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