四川乡城-稻城地区花岗岩地球化学特征及构造背景探讨
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摘要
四川乡城-稻城地区发育4套花岗岩体:包括石英闪长玢岩、花岗细晶岩、二长花岗(细晶)岩和花岗闪长岩,形成时代为印支期到燕山晚期。花岗岩的地球化学研究表明:w(SiO2)=57.82%~81.66%,σ=0.06~2.45,w(K2O+Na2O)=1.38%~7.76%,AR=1.26~2.93,属于亚碱性岩体;ΣREE含量较低,轻稀土相对富集,δEu=0.09~1.28,(La/Yb)N=1.88~11.96,总体表现为右倾型。各套花岗岩微量元素地球化学特征差异明显,相对富集大离子亲石元素,贫化高场强元素,Rb/Sr=0.04~6.18。根据花岗岩的R1-R2,Rb-Yb+Ta,Ta-Yb构造判别图解和区域构造演化史研究,认为二长花岗岩形成于板内构造环境,花岗细晶岩、闪长玢岩和花岗闪长岩形成于岛弧构造环境,其形成与义敦岛弧带碰撞造山活动有关。
Granites in Xiangheng-Daohen areas were mainly composed of quartz-diorite porphyrite,granite aplite,monzonitic granite(aplite)and granodiorite.The age of the granite was from Indosinian to late-Yanshanian.Based on the study of main elements,REE elements and trace elements of the Granites,it was showed that the w(SiO2)=57.82%~81.66%,the Rittmann index(σ)=0.06~2.45,the AR=1.26~2.93,suggesting that the granites belonged to subalkaline.The gross of REE content was low,LREE was relatively rich,δEu=0.09~1.28,(La/Yb)N=1.88~11.96,and the shape of chondrite-normalized REE patterns inclined towards the right.The granites were of great difference in trace elements,relative LILE-enrichment and HFSE-depletion,Rb/Sr=0.04~6.18.The discrimination diagrams of tectonic setting about R1-R2,Rb-Yb+Ta,Ta-Yb and regional tectonic setting evolution revealed that monzonitic granites were formed in continental environment;granite aplite,quartz-diorite porphyrite and granodiorite were foemed in island arc condition.They were resulted from the collision orogenic activities of Yidun island arc.
Granites in Xiangheng-Daohen areas were mainly composed of quartz-diorite porphyrite,granite aplite,monzonitic granite(aplite)and granodiorite.The age of the granite was from Indosinian to late-Yanshanian.Based on the study of main elements,REE elements and trace elements of the Granites,it was showed that the w(SiO2)=57.82%~81.66%,the Rittmann index(σ)=0.06~2.45,the AR=1.26~2.93,suggesting that the granites belonged to subalkaline.The gross of REE content was low,LREE was relatively rich,δEu=0.09~1.28,(La/Yb)N=1.88~11.96,and the shape of chondrite-normalized REE patterns inclined towards the right.The granites were of great difference in trace elements,relative LILE-enrichment and HFSE-depletion,Rb/Sr=0.04~6.18.The discrimination diagrams of tectonic setting about R1-R2,Rb-Yb+Ta,Ta-Yb and regional tectonic setting evolution revealed that monzonitic granites were formed in continental environment;granite aplite,quartz-diorite porphyrite and granodiorite were foemed in island arc condition.They were resulted from the collision orogenic activities of Yidun island arc.
引文
[1]唐菊兴,李佑国.四川乡城-稻城-得荣斑岩型铜矿找矿方向研究报告,2006.
[1]吕伯西,王增,张能德,等.三江地区花岗岩类及其成矿专属性[M].北京:地质出版社,1993,17-60.
[2]侯增谦,曲晓明,周继荣,等.三江地区义敦岛弧碰撞造山过程:花岗岩记录[J].地质学报,2001,75(4):484-497.
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[4]陈旭,李佑国,许模,等.川西地区竹鸡顶铜矿矿床地质特征及矿床成因研究[J].地质与勘探,2008,44(1):42-45.
[5]李仕辉,赵艳.原子吸收光谱分析技术与应用[J].忻州师范学院学报,2008,24(2):25-28.
[6]韩松,董金泉,于福生,等.中子活化分析花岗岩中造岩矿物的稀土和微量元素特征[J].核技术,2005,28(6):445-448.
[7]刘亚轩,张勤,黄珍玉,等.ICP-MS法测定地球化学样品中As,Cr,Ge,V等18种微量痕量元素的研究[J].化学世界,2006(1):16-20.
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[9]Miyashiro A.Volcanic rock series inisland arcs and activecontinental margins[J].American Journal of Science,1974,274:321-355.
[10]周家云,郑荣才,沈冰,等.四川冕宁木洛稀土矿床含矿岩体地球化学特征及其构造意义[J].矿物岩石,2007,27(1):83-89.
[11]谢建成,杨晓勇,Insung Lee.安徽沿江地区燕山期含铜岩体稀土、微量地球化学特征[J].矿物岩石,2008,28(1):72-78.
[12]Boynton W V.Cosmochemistry of the Rare Earth Elements:Meteorite Studies[A].In:Henderson P(ed).Rare Earth Element Geochemis-try[C].Amsterdam:Elsevire Scientific Publishing Company,1984,63-91.
[13]Sun S S,MeDonough WF.Chemical andisotopic systemmatics of oceanic basalts:Implicationfor the mantle composition and process[A].In:Saunder A D,Norry MJ(ed).Geological Society of London Special Publication[C].1989,42:313-345.
[14]费光春,李佑国,陈旭,等.川西乡城-稻城-得荣中带地区浅成花岗岩岩石化学特征及成矿潜力探讨[J].新疆地质,2006,24(3):305-309.
[15]Faure G,Mensing T M.Isotopes:Principles and Applications[M].Third edition.Hoboken,NewJersey:John Wiley&Sons,Inc,2005.
[16]杨岳清,侯增谦,黄典豪,等.中甸弧碰撞造山作用和岩浆成矿系统[J].地球学报,2002,23(1):17-24.
[17]曲晓明,侯增谦,周书贵,等.川西连龙含锡花岗岩的时代与形成构造环境[J].地球学报,2002,23(3):223-228.
[18]曲晓明,侯增谦,唐绍华,等.义敦岛弧带弧后区板内岩浆作用的时代及意义[J].岩石矿物学杂志,2003,22(2):131-137.
[19]Batchelor R A,Bowden P.Petrogenetic interpretation of granitoid rock series using multication parameters[J].Chemical Geology,1985,48(1):43-55.
[20]林清茶,夏斌,张玉泉.云南中甸地区雪鸡坪同碰撞石英闪长玢岩锆石SHRI MP U-Pb定年及其意义[J].地质通报,2006,25(12):133-137.
[21]Pearce J A,Harris N B M,Tindle A G.Trace element discrimination diagrams for the tectonic interpretation of granitic rocks[J].Journal of Petrology,1984,25:956-983.
[1]吕伯西,王增,张能德,等.三江地区花岗岩类及其成矿专属性[M].北京:地质出版社,1993,17-60.
[2]侯增谦,曲晓明,周继荣,等.三江地区义敦岛弧碰撞造山过程:花岗岩记录[J].地质学报,2001,75(4):484-497.
[3]侯增谦,杨岳清,曲晓明,等.三江地区义敦岛弧造山带演化和成矿系统[J].地质学报,2004,78(1):109-120.
[4]陈旭,李佑国,许模,等.川西地区竹鸡顶铜矿矿床地质特征及矿床成因研究[J].地质与勘探,2008,44(1):42-45.
[5]李仕辉,赵艳.原子吸收光谱分析技术与应用[J].忻州师范学院学报,2008,24(2):25-28.
[6]韩松,董金泉,于福生,等.中子活化分析花岗岩中造岩矿物的稀土和微量元素特征[J].核技术,2005,28(6):445-448.
[7]刘亚轩,张勤,黄珍玉,等.ICP-MS法测定地球化学样品中As,Cr,Ge,V等18种微量痕量元素的研究[J].化学世界,2006(1):16-20.
[8]Irvine T N,Baragat WR.Aguide to the chemical classificationof the common volcanic rocks[J].Can J Earth Sci,1971,8:523-548.
[9]Miyashiro A.Volcanic rock series inisland arcs and activecontinental margins[J].American Journal of Science,1974,274:321-355.
[10]周家云,郑荣才,沈冰,等.四川冕宁木洛稀土矿床含矿岩体地球化学特征及其构造意义[J].矿物岩石,2007,27(1):83-89.
[11]谢建成,杨晓勇,Insung Lee.安徽沿江地区燕山期含铜岩体稀土、微量地球化学特征[J].矿物岩石,2008,28(1):72-78.
[12]Boynton W V.Cosmochemistry of the Rare Earth Elements:Meteorite Studies[A].In:Henderson P(ed).Rare Earth Element Geochemis-try[C].Amsterdam:Elsevire Scientific Publishing Company,1984,63-91.
[13]Sun S S,MeDonough WF.Chemical andisotopic systemmatics of oceanic basalts:Implicationfor the mantle composition and process[A].In:Saunder A D,Norry MJ(ed).Geological Society of London Special Publication[C].1989,42:313-345.
[14]费光春,李佑国,陈旭,等.川西乡城-稻城-得荣中带地区浅成花岗岩岩石化学特征及成矿潜力探讨[J].新疆地质,2006,24(3):305-309.
[15]Faure G,Mensing T M.Isotopes:Principles and Applications[M].Third edition.Hoboken,NewJersey:John Wiley&Sons,Inc,2005.
[16]杨岳清,侯增谦,黄典豪,等.中甸弧碰撞造山作用和岩浆成矿系统[J].地球学报,2002,23(1):17-24.
[17]曲晓明,侯增谦,周书贵,等.川西连龙含锡花岗岩的时代与形成构造环境[J].地球学报,2002,23(3):223-228.
[18]曲晓明,侯增谦,唐绍华,等.义敦岛弧带弧后区板内岩浆作用的时代及意义[J].岩石矿物学杂志,2003,22(2):131-137.
[19]Batchelor R A,Bowden P.Petrogenetic interpretation of granitoid rock series using multication parameters[J].Chemical Geology,1985,48(1):43-55.
[20]林清茶,夏斌,张玉泉.云南中甸地区雪鸡坪同碰撞石英闪长玢岩锆石SHRI MP U-Pb定年及其意义[J].地质通报,2006,25(12):133-137.
[21]Pearce J A,Harris N B M,Tindle A G.Trace element discrimination diagrams for the tectonic interpretation of granitic rocks[J].Journal of Petrology,1984,25:956-983.
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