中天山南缘伊尔根布鲁克石英闪长岩锆石U-Pb年龄和地球化学特征
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摘要
中天山位于天山造山带核心部位,对研究中亚造山带西南段构造演化、块体起源和陆壳生长等具重要意义。本次研究围绕中天山伊尔根布鲁克石英闪长岩展开,锆石LA-ICP-MS U-Pb定年获得岩浆结晶年龄为(313.3±5.7)Ma,成岩时代为晚石炭世。花岗岩SiO_2含量58.13%~66.74%,具低CaO含量3.68%~5.79%和高Al_2O_3含量13.02%~13.68%特征。轻重稀土元素分馏明显,富集轻稀土元素,Eu弱正异常或无异常,δEu=0.95~1.3。岩石地球化学研究表明,花岗岩富集大离子亲石元素Ba,Sr,K和亏损高场强元素Nb,Ta,Ti,P,具火山弧花岗岩特征。结合岩石锆石LA-ICP-MS定年结果和区域地质背景,认为伊尔根布鲁克石英闪长岩可能是中天山南缘大洋俯冲消减作用的产物,该区大洋俯冲消减至少延续到晚石炭世。
Chinese Central Tianshan,located in the central part of the Tianshan Orogenic Belt,is of signigicant importance for understanding the tectonic evolution,origination and continental growth of the Central Asian Orogenic Belt.This paper focuses on tectonic implications of quartz diorite intrusions from the Yiergenbuluke at the Southern margin of the Central Tianshan Mountain.Granite intruded at(313.3±5.7) Ma based on the dating results of zircon U-Pb geochromology,it suggested that the granite erupted in Late Carboniferous Epoch. The granite is characterized by SiO2 content from 58.13% ~66.74%,low CaO(3.68~5.79%)and high Al2O3(13.02% ~13.68%).The granite forms a LREE-enriched distribution pattern with a strong contrast between LREE and HREE and the existence of positive or normal Eu anomaly(δEu= 0.95~1.3).Geochemical characteristic of metamorphism andesite suggest that it shows island-arc volcanic chatacteristics,being enriched in LILE such as Ba,Sr,K and depleted in HFSE such as Nb,Ta,Ti,P.In combination with the result of LA-ICP-MS zircon U-Pb dating and regional geological setting,we suggest that the Yiergenbuluke quartz diorite was resulted from the ocean subduction in the Southern margin of the Centre Tianshan Mountain,the oceanic subduction lasted for the Late Carboniferous Epoch.
Chinese Central Tianshan,located in the central part of the Tianshan Orogenic Belt,is of signigicant importance for understanding the tectonic evolution,origination and continental growth of the Central Asian Orogenic Belt.This paper focuses on tectonic implications of quartz diorite intrusions from the Yiergenbuluke at the Southern margin of the Central Tianshan Mountain.Granite intruded at(313.3±5.7) Ma based on the dating results of zircon U-Pb geochromology,it suggested that the granite erupted in Late Carboniferous Epoch. The granite is characterized by SiO2 content from 58.13% ~66.74%,low CaO(3.68~5.79%)and high Al2O3(13.02% ~13.68%).The granite forms a LREE-enriched distribution pattern with a strong contrast between LREE and HREE and the existence of positive or normal Eu anomaly(δEu= 0.95~1.3).Geochemical characteristic of metamorphism andesite suggest that it shows island-arc volcanic chatacteristics,being enriched in LILE such as Ba,Sr,K and depleted in HFSE such as Nb,Ta,Ti,P.In combination with the result of LA-ICP-MS zircon U-Pb dating and regional geological setting,we suggest that the Yiergenbuluke quartz diorite was resulted from the ocean subduction in the Southern margin of the Centre Tianshan Mountain,the oceanic subduction lasted for the Late Carboniferous Epoch.
引文
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[20]舒良树,卢华复,印栋豪,等.中、南天山古生代增生-碰撞事件和变形运动学研究[J].南京大学学报(自然科学),2003,39(1):17-30.
[21]Wang B,Chen Y,Zhan S,et al.Primary Carboniferous and Permian paleomagnetic results from the Yili Block(NW China)and their implications on the geodynamic evolution of Chinese Tianshan Belt[J].Earth&Planetary Science Letters,2007,263(3-4):288-308.
[22]王守敬,王居里.新疆巴伦台钾长花岗岩的地球化学及年代学[J].西北大学学报:自然科学版,2010,40(1):105-110.
[23]Dong Y,Zhang G,Neubauer F,et al.Syn-and post-collisional granitoids in the Central Tianshan orogen:Geochemistry,geochronology and implications for tectonic evolution[J].Gondwana Research,2011,20(2-3):568-581.
[24]Ma X,Shu L,Meert J G,et al.The Paleozoic evolution of Central Tianshan:Geochemical and geochronological evidence[J].Gondwana Research,2014,25(2):797-819.
[25]李向东,王克卓.塔里木盆地西南及邻区特提斯格局和构造意义[J].新疆地质,2000,18(2):113-120.
[26]刘楚雄,许保良,邹天人,等.塔里木北缘及邻区海西期碱性岩岩石化学特征及其大地构造意义[J].新疆地质,2004,22(1):43-49.
[27]姜常义,姜寒冰,叶书锋,等.新疆库鲁克塔格地区二叠纪脉岩群岩石地球化学特征,Nd、Sr、Pb同位素组成与岩石成因[J].地质学报,2005,79(6):823-833.
[28]李曰俊,孙龙德,吴浩若,等.南天山西端乌帕塔尔坎群发现石炭-二叠纪放射虫化石[J].地质科学,2005,40(2):220-226.
[29]Long L,Gao J,Klemd R,et al.Geochemical and geochronological studies of granitoid rocks from the Western Tianshan Orogen:Implications for continental growth in the southwestern Central Asian Orogenic Belt[J].Lithos,2011,126(3):321-340.
[30]Zhang L,Ai Y,Li X,et al.Triassic collision of western Tianshan orogenic belt,China:Evidence from SHRIMP U-Pb dating of zircon from HP/UHP eclogitic rocks[J].Lithos,2007,96(1):266-280.
[31]Andersen T.Correction of common lead in U-Pb analyses that do not report 204Pb[J].Chemical Geology,2002,192(1-2):59-79.
[32]Ludwig KR.Isoplot/Ex version 2.49:A geochronological toolkit for Microsoft Excel[M].Berkeley:Berkeley Geochronology Center Special Publication,2003,La:1-56.
[33]路远发.Geotit:一个用VBA构建的地球化学工具软件包[J].地球化学,2004,33(5):459-464.
[34]Hsokin PWO and Black LP.Metamorphic ziron formation by solid-state recrystallization of protolith igneous zircon[J].Journal of Metamorphic Geology,2000,18:423-439
[35]吴元保,郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学捅报,2004,49(16):1589-1604.
[36]Pearce J A,Harris N B W,Tindle A G.Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks[J].Journal of Petrology,1984,25(4):956-983.
[37]Wilson M.Igneous Petrogenesis:A Global Approach[J].1989.
[38]杨天南,李锦轶,孙桂华,等.中天山早泥盆世陆弧:来自花岗质糜棱岩地球化学及SHRIMP-U/Pb定年的证据[J].岩石学报,2006,22(1):41-48.
[39]陈义兵,张国伟,柳小明,等.中天山巴仑台地区变形花岗岩类LA-ICP-MSU-Pb年代学及其构造意义[J].地质论评,2012,58(1):117-125.
[40]Zhang L,Ai Y,Li X,et al.Triassic collision of western Tianshan orogenic belt,China:Evidence from SHRIMP U-Pb dating of zircon from HP/UHP eclogitic rocks[J].Lithos,2007,96(1):266-280.
[2]Jahn B M,Wu F,Hong D.Important crustal growth in the Phanerozoic:Isotopic evidence of granitoids from east-central Asia[J].Journal of Earth System Science,2000,109(1):5-20.
[3]Jahn B M,Wu F Y,Chen B.Massive granitoid generation in Central Asia:Nd isotope evidence and implication for continental growth in the Phanerozoic.Episodes[J].Episodes,2000,23(2):82-92.
[4]洪大卫,王式洸,谢锡林,等.从中亚正ε_(Nd)值花岗岩看超大陆演化和大陆地壳生长的关系[J].地质学报,2003,77(2):203-209.
[5]Jahn B M.The Central Asian Orogenic Belt and growth of the continental crust in the Phanerozoic[J].Geological Society London Special Publications,2004,226(1):73-100.
[6]胡霭琴,韦刚健,江博明,等.天山0.9Ga新元古代花岗岩SHRIMP锆石U-Pb年龄及其构造意义[J].地球化学,2010,39(3):197-212.
[7]Dong Y,Zhang G,Neubauer F,et al.Syn-and post-collisional granitoids in the Central Tianshan orogen:Geochemistry,geochronology and implications for tectonic evolution[J].Gondwana Research,2011,20(2-3):568-581.
[8]Lei R X,Wu C Z,Gu L X,et al.Zircon U-Pb chronology and Hf isotope of the Xingxingxia granodiorite from the Central Tianshan zone(NW China):Implications for the tectonic evolution of the southern Altaids[J].Gondwana Research,2011,20(2-3):582-593.
[9]陈义兵,张国伟,柳小明,等.中天山巴仑台地区变形花岗岩类LA-ICP-MSU-Pb年代学及其构造意义[J].地质论评,2012,58(1):117-125.
[10]He Z Y,Zhang Z M,Zong K Q,et al.Zircon U-Pb and Hf isotopic studies of the Xingxingxia Complex from Eastern Tianshan(NW China):Significance to the reconstruction and tectonics of the southern Central Asian Orogenic Belt[J].Lithos,2014,s 190-191(2):485-499.
[11]Gao J,Li M,Xiao X,et al.Paleozoic tectonic evolution of the Tianshan Orogen,northwestern China[J].Tectonophysics,1998,287(1-4):213-231.
[12]李锦轶,肖序常.对新疆地壳结构与构造演化几个问题的简要评述[J].地质科学,1999(4):405-419.
[13]Xiao W J.Paleozoic accretionary and collisional tectonics of the eastern Tianshan(China):Implications for the continental growth of central Asia[J].Social Compass,2004,304(1):85-98.
[14]董云鹏,周鼎武,张国伟,等.中天山北缘干沟蛇绿混杂岩带的地质地球化学[J].岩石学报,2006,22(1):49-56.
[15]高俊,龙灵利,钱青,黄德志,苏文,Klemd R.南天山:晚古生代还是三叠纪碰撞造山带?[J].岩石学报,2006,22(5):1049-1061.
[16]李锦轶,王克桌,李亚萍,孙桂花,褚春华,李丽群,朱志新.天山山脉地貌特征、地壳组成与地质演化[J].地质通报,2006,25(8):895-909.
[17]朱志新,李锦轶,董连慧,等.新疆西天山古生代侵入岩的地质特征及构造意义[J].地学前缘,2011,18(2):170-179.
[18]Ma X,Shu L,Meert J G.Early Permian slab breakoff in the Chinese Tianshan belt inferred from the post-collisional granitoids[J].Gondwana Research,2015,27(1):228-243.
[19]张元元,郭召杰.准噶尔北部蛇绿岩形成时限新证据及其东、西准噶尔蛇绿岩的对比研究[J].岩石学报,2010,26(2):422-430.
[20]舒良树,卢华复,印栋豪,等.中、南天山古生代增生-碰撞事件和变形运动学研究[J].南京大学学报(自然科学),2003,39(1):17-30.
[21]Wang B,Chen Y,Zhan S,et al.Primary Carboniferous and Permian paleomagnetic results from the Yili Block(NW China)and their implications on the geodynamic evolution of Chinese Tianshan Belt[J].Earth&Planetary Science Letters,2007,263(3-4):288-308.
[22]王守敬,王居里.新疆巴伦台钾长花岗岩的地球化学及年代学[J].西北大学学报:自然科学版,2010,40(1):105-110.
[23]Dong Y,Zhang G,Neubauer F,et al.Syn-and post-collisional granitoids in the Central Tianshan orogen:Geochemistry,geochronology and implications for tectonic evolution[J].Gondwana Research,2011,20(2-3):568-581.
[24]Ma X,Shu L,Meert J G,et al.The Paleozoic evolution of Central Tianshan:Geochemical and geochronological evidence[J].Gondwana Research,2014,25(2):797-819.
[25]李向东,王克卓.塔里木盆地西南及邻区特提斯格局和构造意义[J].新疆地质,2000,18(2):113-120.
[26]刘楚雄,许保良,邹天人,等.塔里木北缘及邻区海西期碱性岩岩石化学特征及其大地构造意义[J].新疆地质,2004,22(1):43-49.
[27]姜常义,姜寒冰,叶书锋,等.新疆库鲁克塔格地区二叠纪脉岩群岩石地球化学特征,Nd、Sr、Pb同位素组成与岩石成因[J].地质学报,2005,79(6):823-833.
[28]李曰俊,孙龙德,吴浩若,等.南天山西端乌帕塔尔坎群发现石炭-二叠纪放射虫化石[J].地质科学,2005,40(2):220-226.
[29]Long L,Gao J,Klemd R,et al.Geochemical and geochronological studies of granitoid rocks from the Western Tianshan Orogen:Implications for continental growth in the southwestern Central Asian Orogenic Belt[J].Lithos,2011,126(3):321-340.
[30]Zhang L,Ai Y,Li X,et al.Triassic collision of western Tianshan orogenic belt,China:Evidence from SHRIMP U-Pb dating of zircon from HP/UHP eclogitic rocks[J].Lithos,2007,96(1):266-280.
[31]Andersen T.Correction of common lead in U-Pb analyses that do not report 204Pb[J].Chemical Geology,2002,192(1-2):59-79.
[32]Ludwig KR.Isoplot/Ex version 2.49:A geochronological toolkit for Microsoft Excel[M].Berkeley:Berkeley Geochronology Center Special Publication,2003,La:1-56.
[33]路远发.Geotit:一个用VBA构建的地球化学工具软件包[J].地球化学,2004,33(5):459-464.
[34]Hsokin PWO and Black LP.Metamorphic ziron formation by solid-state recrystallization of protolith igneous zircon[J].Journal of Metamorphic Geology,2000,18:423-439
[35]吴元保,郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学捅报,2004,49(16):1589-1604.
[36]Pearce J A,Harris N B W,Tindle A G.Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks[J].Journal of Petrology,1984,25(4):956-983.
[37]Wilson M.Igneous Petrogenesis:A Global Approach[J].1989.
[38]杨天南,李锦轶,孙桂华,等.中天山早泥盆世陆弧:来自花岗质糜棱岩地球化学及SHRIMP-U/Pb定年的证据[J].岩石学报,2006,22(1):41-48.
[39]陈义兵,张国伟,柳小明,等.中天山巴仑台地区变形花岗岩类LA-ICP-MSU-Pb年代学及其构造意义[J].地质论评,2012,58(1):117-125.
[40]Zhang L,Ai Y,Li X,et al.Triassic collision of western Tianshan orogenic belt,China:Evidence from SHRIMP U-Pb dating of zircon from HP/UHP eclogitic rocks[J].Lithos,2007,96(1):266-280.