江西冷水坑矿田火山-岩浆活动时限:SHRIMP锆石U-Pb年龄证据
摘要
冷水坑铅锌银矿是武夷山北缘中生代火山岩带中独具特色的斑岩型矿床,含矿花岗斑岩侵位于打鼓顶组和鹅湖岭组火山岩地层中。笔者采用SHRIMP锆石U-Pb测年技术,对冷水坑矿田含矿花岗斑岩与鹅湖岭组晶屑凝灰岩进行了年代学研究。3个晶屑凝灰岩的锆石U-Pb年龄分别为(157.8±1.6)Ma、(157.2±1.5)Ma和(158.2±1.8)Ma,花岗斑岩形成于(157.6±1.3)Ma。含矿斑岩与其赋存的火山岩活动时间高度一致,是同一构造岩浆活动的产物。与区域上其他火山盆地不同,冷水坑矿田鹅湖岭组与打鼓顶组火山岩属于侏罗系。广泛发育于武夷山北坡中生代火山岩盆地的打鼓顶组与鹅湖岭组火山岩,其活动时间在不同火山盆地也各不相同,不能简单地统一划归为侏罗纪或白垩纪,这套地层的时代应予以重新厘定。区域上该套火山岩活动时间的差异,指示武夷山北缘火山岩浆活动具有阶段性或间隙性的演化过程,且构造背景也有很大不同。冷水坑矿田火山岩与含矿斑岩形成于中国东部陆内挤压构造环境。
The Lengshuikeng lend-zinc silver deposit is a porphyry deposit located in northern Wuyi Mountain Mesozoic volcanic belt.The ore-bearing porphyry intruded Daguding Formation and Ehuling Formation volcanic strata.Based on an analysis of the mineralization feature of the deposit,the authas determined SHRIMP zircon U-Pb ages of the ore-bearing porphyry and crystal stuff of Ehuling Formation in the Lengshuikeng orefield.Zircon U-Pb dating yields ages of(157.8±1.6) Ma、(157.2±1.5) Ma and(158.2±1.8) Ma for the volcanic rocks and(157.6±1.3) Ma for the porphyry,respectively.The highly consistent activity time for the ore-bearing porphyry and the volcano rock in the orefield suggests that they resulted from the same tectonic magmatic activity.The age of volcano rocks of Daguding Formation and Ehuling Formation are Jurassic,completely different from the ages of volcanic rock in other Mesozoic volcanic basin in northern Wuyi Mountain area.The Daguding Formation and Ehuling Formation volcanic rocks,which are widely distributed in the Mesozoic volcanic basins on the north slope of the Wuyi Mountain area,were formed in different periods in different basins.Those volcanic strata in this area should be reclassified.The time difference of volcanic activities in different basis implies the stages or interstitial evolution process for the volcano-magmatic activities in northern Wuyi Mountain and in different tectonic settings.The ore-bearing porphyry and the volcanic rocks in the Lengshuikeng orefield were formed in Mesozoic continental extrusion setting in eastern China.
The Lengshuikeng lend-zinc silver deposit is a porphyry deposit located in northern Wuyi Mountain Mesozoic volcanic belt.The ore-bearing porphyry intruded Daguding Formation and Ehuling Formation volcanic strata.Based on an analysis of the mineralization feature of the deposit,the authas determined SHRIMP zircon U-Pb ages of the ore-bearing porphyry and crystal stuff of Ehuling Formation in the Lengshuikeng orefield.Zircon U-Pb dating yields ages of(157.8±1.6) Ma、(157.2±1.5) Ma and(158.2±1.8) Ma for the volcanic rocks and(157.6±1.3) Ma for the porphyry,respectively.The highly consistent activity time for the ore-bearing porphyry and the volcano rock in the orefield suggests that they resulted from the same tectonic magmatic activity.The age of volcano rocks of Daguding Formation and Ehuling Formation are Jurassic,completely different from the ages of volcanic rock in other Mesozoic volcanic basin in northern Wuyi Mountain area.The Daguding Formation and Ehuling Formation volcanic rocks,which are widely distributed in the Mesozoic volcanic basins on the north slope of the Wuyi Mountain area,were formed in different periods in different basins.Those volcanic strata in this area should be reclassified.The time difference of volcanic activities in different basis implies the stages or interstitial evolution process for the volcano-magmatic activities in northern Wuyi Mountain and in different tectonic settings.The ore-bearing porphyry and the volcanic rocks in the Lengshuikeng orefield were formed in Mesozoic continental extrusion setting in eastern China.
引文
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宋彪,张玉海,刘敦一.2002b.微理原位分析仪器SHRI MP的产生与锆石同位素地质年代学[J].质谱学报,23(1):58-62.
杨水源,蒋少涌,姜耀辉,赵葵东,范洪海.2010.江西相山流纹英安岩和流纹英安斑岩锆石U-Pb年代学和Hf同位素组成及其地质意义[J].中国科学:地球科学,40(8):953-969.
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张利民.1996.试论我国东部火山岩型铀矿床赋存层位的地质时代[J].铀矿地质,12(3):139-143.
张万良.2000.盛源盆地火山岩系地层的时代归属[J].铀矿地质,16(2):99-101.
左力艳,孟祥金,杨竹森.2008.冷水坑斑岩型银铅锌矿床含矿岩系岩石地球化学及Sr、Nd同位素研究[J].矿床地质,27(3):367-382.
左力艳,侯增谦,孟祥金,杨志明,宋玉财,李政.2010.冷水坑斑岩型银铅锌矿床含矿斑岩锆石SHRI MP U-Pb年代学研究[J].中国地质,37(5):1450-1457.
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Jiang Y H,Ling HF,Jiang S Y,Fan HH,Shen WZand Ni P.2005.Petrogenesis of a Late Jurassic peraluminous volcanic complex andits high-Mg,potassic,quenched enclaves at Xiangshan,SoutheastChina[J].J.Petrol.,46:1121-1154.
Ludwig K R.2001.Users manual for isoplot/Ex(rev.2.49):Ageochronologica toolkit for Microsoft Excel[R].BerkeleyGeochronology Center.Special Publication No.l,1-55.
Williams I S and Claesson S.1987.Isotopic evidence for the Precambri-an provenance and Caledonian metamorphismof high grade parag-neisses fromthe Seve Nappes,Scandanavia Caledonides:II.Ionmicroprobe zircon U-Th-Pb[J].Contrib.Mineral.Petrol.,97:205-217.
Williams I S,Buick S and Cartwright I.1996.An extended episode ofearly Mesoproterozoic metamorphic fluid flow in the ReynoldsRange,central Australia[J].J.Metamorph Geol.,14:29-47.
Williams I S.1998.U-Th-Pb geochronology byion microprobe[A].In:Mckibben M A,Shanks Iii WC,eds.Applications of microanaly-tical techniques to understanding mineralizing processes[C].Rev.Econ.Geol.,7:1-35.
陈迪云,周文斌,周鲁民,吴伯林,谭敬华,孙占学.1993.相山铀矿田同位素地质学特征[J].矿床地质,12(4):370-377.
方锡珩,侯文尧,万国良.1982.相山破火山口火山杂岩体的岩石学研究[J].岩矿测试,1(1):1-10.
江西地质矿产局.1982.江西省区域地质志[M].北京:地质出版社.1-921.
李坤英,沈加林,王小平.1989.中国浙闽赣地区中生代陆相火山岩同位素年代学[J].地层学杂志,13(1):1-13.
李兆鼐,权恒,李之彤,毛建仁,李汉声,吴才来,郝艳丽,张招崇,王碧香,刘焰.2003.中国东部中新生代火成岩及其深部过程[M].北京:地质出版社.1-357.
孟祥金,董光裕,刘建光,左力艳,何细荣,赵志刚,黄振强,宁晋南,杨小朋,饶克辛,杨存来.2007.江西冷水坑斑岩型铅锌银矿床[M].北京:地质出版社.1-148.
孟祥金,侯增谦,董光裕,刘建光,左力艳,杨竹森,肖茂章.2009.江西冷水坑斑岩型铅锌银矿床地质特征、热液蚀变与成矿时限[J].地质学报,83(12):1951-1967.
宋彪,张玉海,万渝生,简平.2002a.锆石SHRI MP样品靶制作、年龄测定及有关现象讨论[J].地质论评,48(增刊):26-30.
宋彪,张玉海,刘敦一.2002b.微理原位分析仪器SHRI MP的产生与锆石同位素地质年代学[J].质谱学报,23(1):58-62.
杨水源,蒋少涌,姜耀辉,赵葵东,范洪海.2010.江西相山流纹英安岩和流纹英安斑岩锆石U-Pb年代学和Hf同位素组成及其地质意义[J].中国科学:地球科学,40(8):953-969.
叶庆同.1987.赣东北铅锌矿床成矿系列和成矿机理[M].北京:北京科学技术出版社.1-104.
张利民.1996.试论我国东部火山岩型铀矿床赋存层位的地质时代[J].铀矿地质,12(3):139-143.
张万良.2000.盛源盆地火山岩系地层的时代归属[J].铀矿地质,16(2):99-101.
左力艳,孟祥金,杨竹森.2008.冷水坑斑岩型银铅锌矿床含矿岩系岩石地球化学及Sr、Nd同位素研究[J].矿床地质,27(3):367-382.
左力艳,侯增谦,孟祥金,杨志明,宋玉财,李政.2010.冷水坑斑岩型银铅锌矿床含矿斑岩锆石SHRI MP U-Pb年代学研究[J].中国地质,37(5):1450-1457.
Compston W,Williams I S and Meyer C E.1984.U-Pb geochronologyof zircons fromlunar breccia73217using a sensitive high mass-resolutionion microprobe[J].J.Geophys Res.,89:B525-B534.
Compston W,Williams I S,Kirschvink J L,Zhang Z and Guogan M.1992.Zircon U-Pb ages for the Early Cambrian ti me-scale[J].J.Geol.Soc.,149:171-184.
Feng R,Machado Nand Ludden J.1993.Lead geochronology of zirconby LaserProbe-inductively coupled plasma mass spectrometry(LP-ICPMS)[J].Geochi m.Cosmochi m.Acta,57:3479-3486.
Jiang Y H,Ling HF,Jiang S Y,Fan HH,Shen WZand Ni P.2005.Petrogenesis of a Late Jurassic peraluminous volcanic complex andits high-Mg,potassic,quenched enclaves at Xiangshan,SoutheastChina[J].J.Petrol.,46:1121-1154.
Ludwig K R.2001.Users manual for isoplot/Ex(rev.2.49):Ageochronologica toolkit for Microsoft Excel[R].BerkeleyGeochronology Center.Special Publication No.l,1-55.
Williams I S and Claesson S.1987.Isotopic evidence for the Precambri-an provenance and Caledonian metamorphismof high grade parag-neisses fromthe Seve Nappes,Scandanavia Caledonides:II.Ionmicroprobe zircon U-Th-Pb[J].Contrib.Mineral.Petrol.,97:205-217.
Williams I S,Buick S and Cartwright I.1996.An extended episode ofearly Mesoproterozoic metamorphic fluid flow in the ReynoldsRange,central Australia[J].J.Metamorph Geol.,14:29-47.
Williams I S.1998.U-Th-Pb geochronology byion microprobe[A].In:Mckibben M A,Shanks Iii WC,eds.Applications of microanaly-tical techniques to understanding mineralizing processes[C].Rev.Econ.Geol.,7:1-35.
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