青海野马泉铁锌矿床二长花岗岩锆石U-Pb和金云母Ar-Ar测年及地质意义
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摘要
青海野马泉铁锌矿床地处祁漫塔格山与柴达木盆地之间的盆山结合部位,是矽卡岩型铁锌多金属矿床。矿体均呈隐伏?半隐伏状产出、具多期次强烈岩浆活动叠加等特征。长期以来,有关野马泉铁锌多金属矿床的成矿岩体和成矿时代众说纷纭,制约了对该矿床成因机制的认识及进一步的矿产勘查工作。本文基于详细的野外实地调查和矿床地质特征解剖,开展了成岩成矿年龄精测,探讨了成矿构造环境。铁锌矿体产于二长花岗岩与围岩地层的外接触带,发育石榴子石、透辉石、金云母、绿帘石等矽卡岩化作用。利用LA-ICP-MS锆石U-Pb法,获得成矿二长花岗岩的年龄为229.5±2.2 Ma(n=22,MSWD=1.3);采用Ar-Ar分步升温法获得与磁铁矿共生的金云母坪年龄为222.0±1.3 Ma(MSWD=0.41)、等时线年龄为222.4±2.5 Ma(MSWD=1.4),证实野马泉铁锌多金属矿床形成于晚三叠世,成矿岩体属过铝质、高钾钙碱性系列,为I-A过渡型花岗岩,具有高SiO_2,高K_2O/Na_2O,低P_2O_5,低Sr高Yb的特点。结合区域其他多金属矿床最新成岩成矿年代学数据,认为野马泉矿床形成于东昆仑地区海西?印支造山旋回晚期、由碰撞向后碰撞转换的地质构造环境。
The Yemaquan iron-zinc deposit is a typical skarn-type deposit located in the border area between the Qimantage orogenic zone and the Qadam Basin.A few concealed or semi-concealed ore bodies have been explored in this deposit.However,the lack of information regarding the ages of ore-related granite and ore-formation restricts the understanding of the genesis and further exploration.U-Pb dating of zircons from the ore related monzogranite yielded an age of 229.5±2.2 Ma(n=22,MSWD=1.3),while Ar-Ar analysis of phlogopite associated with magnetite gave a plateau age of 222.0±1.3 Ma(MSWD=0.41)and isochron age of 222.4±2.5 Ma(MSWD=1.4).The dating results indicated that the Yemaquan Fe-Zn deposit was formed in the Middle to Late Triassic.The monzogranite rocks have high SiO_2 contents,high K_2O/Na_2O ratios,low P_2O_5 contents and Sr/Yb ratios.Combining with the available petrogenetic and metallogenic ages and regional tectonic research works,it is suggested that the compression to extension transition during the Late Paleozoic to Early Mesozoic led to the formation of the widely distributed granitic intrusions and a large number of porphyry and skarn-type poly-metallic deposits in the Qimantage area.
The Yemaquan iron-zinc deposit is a typical skarn-type deposit located in the border area between the Qimantage orogenic zone and the Qadam Basin.A few concealed or semi-concealed ore bodies have been explored in this deposit.However,the lack of information regarding the ages of ore-related granite and ore-formation restricts the understanding of the genesis and further exploration.U-Pb dating of zircons from the ore related monzogranite yielded an age of 229.5±2.2 Ma(n=22,MSWD=1.3),while Ar-Ar analysis of phlogopite associated with magnetite gave a plateau age of 222.0±1.3 Ma(MSWD=0.41)and isochron age of 222.4±2.5 Ma(MSWD=1.4).The dating results indicated that the Yemaquan Fe-Zn deposit was formed in the Middle to Late Triassic.The monzogranite rocks have high SiO_2 contents,high K_2O/Na_2O ratios,low P_2O_5 contents and Sr/Yb ratios.Combining with the available petrogenetic and metallogenic ages and regional tectonic research works,it is suggested that the compression to extension transition during the Late Paleozoic to Early Mesozoic led to the formation of the widely distributed granitic intrusions and a large number of porphyry and skarn-type poly-metallic deposits in the Qimantage area.
引文
陈文,张彦,金贵善,张岳桥.2006.青藏高原东南缘晚新生代幕式抬升作用的Ar-Ar热年代学证据.岩石学报,22(4):867-872.
邓晋福,罗照华,苏尚国,莫宣学,于炳松,赖兴运,谌宏伟.2004.岩石成因、构造环境与成矿作用.北京:地质出版社:1-381
丰成友,李东生,屈文俊,杜安道,王松,苏生顺,江军华.2009.青海祁漫塔格索拉吉尔矽卡岩型铜钼矿床辉钼矿Re-Os同位素定年及其意义.岩矿测试,28(3):223-237.
丰成友,王松,李国臣,马圣钞,李东生.2012.青海祁漫塔格中晚三叠世花岗岩:年代学、地球化学及成矿意义.岩石学报,28(2):665-678.
丰成友,王雪萍,舒晓峰,张爱奎,肖晔,刘建楠,马圣钞,李国臣,李大新.2011.青海祁漫塔格虎头崖铅锌多金属矿区年代学研究及地质意义.吉林大学学报(地球科学版),41(6):1806-1816.
高永宝,李文渊,李侃,钱兵,李东生,何书跃,张照伟,张江伟.2014.东昆仑野马泉铁矿有关花岗岩年代学、地球化学、Hf同位素特征.岩石学报,36(6):1647-1665.
高永宝,李文渊,马晓光,张照伟,汤庆艳.2012.东昆仑尕林格铁矿床成因年代学及Hf同位素制约.兰州大学学报(自然科学版),48(2):36-47.
郭正府,邓晋福,许志琴,莫宣学,罗照华.1998.青藏东昆仑晚古生代末?中生代中酸性火成岩与陆内造山过程.现代地质,12(3):344-352.
侯可军,李延河,田有荣.2009.LA-MC-ICP-MS锆石微区原位U-Pb定年技术.矿床地质,28(4):481-492.
刘成东,莫宣学,罗照华,喻学惠,谌宏伟,李述为,赵欣.2004.东昆仑壳?幔岩浆混合作用:来自锆石SHRIMP年代学的证据.科学通报,49(6):596-602.
刘建楠,丰成友,赵一鸣,李大新,肖晔,周建厚,马永寿.2013.青海野马泉矽卡岩型铁锌多金属矿区侵入岩、交代岩及矿化蚀变特征.矿床地质,32(1):77-94.
刘云华,莫宣学,喻学惠,张雪亭,许国武.2006.东昆仑野马地区景忍花岗岩锆石SHRIMP U-Pb定年及其地质意义.岩石学报,22(10):2457-2463.
毛景文,周振华,丰成友,王义天,张长青,彭慧娟,于淼.2012.初论中国三叠纪大规模成矿作用及其动力学背景.中国地质,39(6):1437-1471.
莫宣学,罗照华,邓晋福,喻学惠,刘成东,谌宏伟,袁万明,刘云华.2007.东昆仑造山带花岗岩及地壳生长.高校地质学报,13(3):403-414.
潘桂棠,李兴振,王立全,丁俊,陈智粱.2002.青藏高原及邻区大地构造单元初步划分.地质通报,21(11):701-707.
宋忠宝,贾群子,张占玉,何书跃,陈向阳,全守村,栗亚芝,张雨莲,张晓飞.2010.东昆仑祁漫塔格地区野马泉铁铜矿床地质特征及成因探讨.西北地质,43(4):209-217.
田承盛,丰成友,李军红,曹德智.2013.青海它温察汉铁多金属矿床40Ar-39Ar年代学研究及意义.矿床地质,32(1):169-176.
吴祥珂,孟繁聪,许虹,崔美慧.2011.青海祁漫塔格玛兴大坂晚三叠世花岗岩年代学、地球化学及Nd-Hf同位素组成.岩石学报,27(11):3380-3394.
肖晔,丰成友,刘建楠,于淼,周建厚,李大新,赵一鸣.2013.青海肯德可克铁多金属矿区年代学及硫同位素特征.矿床地质,32(1):177-186.
于淼,丰成友,刘洪川,李定武,赵一鸣,李大新,刘建楠,王辉,张明辉.2015.青海尕林格矽卡岩型铁矿金云母40Ar/39Ar年代学及成矿地质意义.地质学报,89(3):510-521
张彦,陈文,陈克龙,刘新宇.2006.成岩混层(I/S)Ar-Ar年龄谱型及39Ar核反冲丢失机理研究--以浙江长兴地区P-T界线粘土岩为例.地质论评,52(4):556-561.
赵一鸣,林文蔚,毕承思,李大新,蒋崇俊.2012.中国矽卡岩矿床.北京:地质出版社:1-411.
赵振华.2007.关于岩石微量元素构造环境判别图解使用的有关问题.大地构造与成矿学,31(2):92-103.
Andersen T.2005.Detrital zircons as tracers of sedimentary provenance:Limiting conditions from statistics and numerical simulation.Chemical Geology,216:249-270.
Chappell B W and White A J R.2001.Two contrasting granite types:25 years later.Australian Journal of Earth Sciences,48(4):489-499.
Elhlou S,Belousova E,Griffin W L,Peaarson N G and O’Reilly S Y.2006.Trace element and isotopic composition of GJ-red zircon standard by laser ablation.Geochimica et Cosmochimica Acta,70(S1):158.
Giletti B J and Tullis J.1977.Studies in diffusion:Pressure dependence of Ar diffusion in phlogopite mica.Earth and Planetary Science Letters,35:180-183.
Liu Y S,Hu Z C,Gao S,Gunther D,Xu J,Gao C G and Chen H H.2008.In situ analysis of major and trace elements of anhydrous minerals by LA-MC-ICP-MSwithout applying an internal standard.Chemical Geology,257(1-2):34-43.
Maniar P D and Piccoli P M 1989.Tectonic discrimination of granitoids.Geological Society of America Bulletin,101(5):635-643.
Meinert L D,Dipple G M and Nicolescu S.2005.World skarn deposits.Economic Geology,Society of Economic Geologist in Economical Geology 100th Anniversary Volume:229-336
Nasdala L,Hofmeister W,Norberg N,Mattinson J M,Corfu F,Dor W,Kamo S L,Kennedy A K,Kronz A,Reiners PW,Frei D,Kosler J,Wan Y,Gotze J,Hager T,Kroner Aand Valley J.2008.Zircon M257-A homogeneous natural reference material forthe ion microp robe U-Pb analysis of zircon.Geostandards and Geoanalytical Research,32:247-265.
Pearce J A,Harris B N W and Tindle A G.1984.Trace element discrimination diagrams for the tectonic interpretation of granite rocks.Journal of Petrology,25:956-983.
Rickwood P C.1989.Boundary lines within petrologic diagrams which use oxides of minor elements.Lithos,22:247-263.
Sun S S and Mc Donough W F.1989.Chemical and isotopic systematic of oceanic basalts:Implications for mantle composition and process//Sanders A D and Norry M J.Magmatism in the Ocean Basins.Geological Society,London,Special Publications,42:313-345.
Whalen J B,Currie K L and Chappell B W.1987.A-type granites:Geochemical characteristics,discrimination and petrogenesis.Contributions to Mineralogy and Petrology,95:407-419.
邓晋福,罗照华,苏尚国,莫宣学,于炳松,赖兴运,谌宏伟.2004.岩石成因、构造环境与成矿作用.北京:地质出版社:1-381
丰成友,李东生,屈文俊,杜安道,王松,苏生顺,江军华.2009.青海祁漫塔格索拉吉尔矽卡岩型铜钼矿床辉钼矿Re-Os同位素定年及其意义.岩矿测试,28(3):223-237.
丰成友,王松,李国臣,马圣钞,李东生.2012.青海祁漫塔格中晚三叠世花岗岩:年代学、地球化学及成矿意义.岩石学报,28(2):665-678.
丰成友,王雪萍,舒晓峰,张爱奎,肖晔,刘建楠,马圣钞,李国臣,李大新.2011.青海祁漫塔格虎头崖铅锌多金属矿区年代学研究及地质意义.吉林大学学报(地球科学版),41(6):1806-1816.
高永宝,李文渊,李侃,钱兵,李东生,何书跃,张照伟,张江伟.2014.东昆仑野马泉铁矿有关花岗岩年代学、地球化学、Hf同位素特征.岩石学报,36(6):1647-1665.
高永宝,李文渊,马晓光,张照伟,汤庆艳.2012.东昆仑尕林格铁矿床成因年代学及Hf同位素制约.兰州大学学报(自然科学版),48(2):36-47.
郭正府,邓晋福,许志琴,莫宣学,罗照华.1998.青藏东昆仑晚古生代末?中生代中酸性火成岩与陆内造山过程.现代地质,12(3):344-352.
侯可军,李延河,田有荣.2009.LA-MC-ICP-MS锆石微区原位U-Pb定年技术.矿床地质,28(4):481-492.
刘成东,莫宣学,罗照华,喻学惠,谌宏伟,李述为,赵欣.2004.东昆仑壳?幔岩浆混合作用:来自锆石SHRIMP年代学的证据.科学通报,49(6):596-602.
刘建楠,丰成友,赵一鸣,李大新,肖晔,周建厚,马永寿.2013.青海野马泉矽卡岩型铁锌多金属矿区侵入岩、交代岩及矿化蚀变特征.矿床地质,32(1):77-94.
刘云华,莫宣学,喻学惠,张雪亭,许国武.2006.东昆仑野马地区景忍花岗岩锆石SHRIMP U-Pb定年及其地质意义.岩石学报,22(10):2457-2463.
毛景文,周振华,丰成友,王义天,张长青,彭慧娟,于淼.2012.初论中国三叠纪大规模成矿作用及其动力学背景.中国地质,39(6):1437-1471.
莫宣学,罗照华,邓晋福,喻学惠,刘成东,谌宏伟,袁万明,刘云华.2007.东昆仑造山带花岗岩及地壳生长.高校地质学报,13(3):403-414.
潘桂棠,李兴振,王立全,丁俊,陈智粱.2002.青藏高原及邻区大地构造单元初步划分.地质通报,21(11):701-707.
宋忠宝,贾群子,张占玉,何书跃,陈向阳,全守村,栗亚芝,张雨莲,张晓飞.2010.东昆仑祁漫塔格地区野马泉铁铜矿床地质特征及成因探讨.西北地质,43(4):209-217.
田承盛,丰成友,李军红,曹德智.2013.青海它温察汉铁多金属矿床40Ar-39Ar年代学研究及意义.矿床地质,32(1):169-176.
吴祥珂,孟繁聪,许虹,崔美慧.2011.青海祁漫塔格玛兴大坂晚三叠世花岗岩年代学、地球化学及Nd-Hf同位素组成.岩石学报,27(11):3380-3394.
肖晔,丰成友,刘建楠,于淼,周建厚,李大新,赵一鸣.2013.青海肯德可克铁多金属矿区年代学及硫同位素特征.矿床地质,32(1):177-186.
于淼,丰成友,刘洪川,李定武,赵一鸣,李大新,刘建楠,王辉,张明辉.2015.青海尕林格矽卡岩型铁矿金云母40Ar/39Ar年代学及成矿地质意义.地质学报,89(3):510-521
张彦,陈文,陈克龙,刘新宇.2006.成岩混层(I/S)Ar-Ar年龄谱型及39Ar核反冲丢失机理研究--以浙江长兴地区P-T界线粘土岩为例.地质论评,52(4):556-561.
赵一鸣,林文蔚,毕承思,李大新,蒋崇俊.2012.中国矽卡岩矿床.北京:地质出版社:1-411.
赵振华.2007.关于岩石微量元素构造环境判别图解使用的有关问题.大地构造与成矿学,31(2):92-103.
Andersen T.2005.Detrital zircons as tracers of sedimentary provenance:Limiting conditions from statistics and numerical simulation.Chemical Geology,216:249-270.
Chappell B W and White A J R.2001.Two contrasting granite types:25 years later.Australian Journal of Earth Sciences,48(4):489-499.
Elhlou S,Belousova E,Griffin W L,Peaarson N G and O’Reilly S Y.2006.Trace element and isotopic composition of GJ-red zircon standard by laser ablation.Geochimica et Cosmochimica Acta,70(S1):158.
Giletti B J and Tullis J.1977.Studies in diffusion:Pressure dependence of Ar diffusion in phlogopite mica.Earth and Planetary Science Letters,35:180-183.
Liu Y S,Hu Z C,Gao S,Gunther D,Xu J,Gao C G and Chen H H.2008.In situ analysis of major and trace elements of anhydrous minerals by LA-MC-ICP-MSwithout applying an internal standard.Chemical Geology,257(1-2):34-43.
Maniar P D and Piccoli P M 1989.Tectonic discrimination of granitoids.Geological Society of America Bulletin,101(5):635-643.
Meinert L D,Dipple G M and Nicolescu S.2005.World skarn deposits.Economic Geology,Society of Economic Geologist in Economical Geology 100th Anniversary Volume:229-336
Nasdala L,Hofmeister W,Norberg N,Mattinson J M,Corfu F,Dor W,Kamo S L,Kennedy A K,Kronz A,Reiners PW,Frei D,Kosler J,Wan Y,Gotze J,Hager T,Kroner Aand Valley J.2008.Zircon M257-A homogeneous natural reference material forthe ion microp robe U-Pb analysis of zircon.Geostandards and Geoanalytical Research,32:247-265.
Pearce J A,Harris B N W and Tindle A G.1984.Trace element discrimination diagrams for the tectonic interpretation of granite rocks.Journal of Petrology,25:956-983.
Rickwood P C.1989.Boundary lines within petrologic diagrams which use oxides of minor elements.Lithos,22:247-263.
Sun S S and Mc Donough W F.1989.Chemical and isotopic systematic of oceanic basalts:Implications for mantle composition and process//Sanders A D and Norry M J.Magmatism in the Ocean Basins.Geological Society,London,Special Publications,42:313-345.
Whalen J B,Currie K L and Chappell B W.1987.A-type granites:Geochemical characteristics,discrimination and petrogenesis.Contributions to Mineralogy and Petrology,95:407-419.