青海多彩地区龙墨沟辉绿岩脉锆石U-Pb年代学及其地质意义
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摘要
多彩地区位于羌塘地块东北缘,其内发育的大量晚古生代-中生代岩浆岩为研究古特提斯洋构造演化提供了重要证据。选取龙墨沟地区出露的辉绿岩脉为研究对象,采用LA-ICP-MS锆石U-Pb定年的方法进行了测试分析,探讨了成岩年代学及其地质意义。定年结果表明龙墨沟辉绿岩侵位年龄为(248.3±2.6)Ma,为早三叠世岩浆活动产物;与区内其他岩浆岩研究成果的对比分析表明,龙墨沟辉绿岩可能产于龙木错-双湖洋俯冲产生的弧后伸展背景下。
The Duocai area is located in the northeastern margin of the Qiangtang terrane.In this area,Permian to Triassic magmatic rocks are widespread because of the subduction of Palaeo-Tethyan oceans and the final closure.We take the Longmogou diabase as the research object,and details the researches on its zircon U-Pb geochronology.The result shows that the diabase has crystalline age of(248.3±2.6)Ma and thus constrains its formation time to the Early Triassic.Cosidering previously published data,we suggest that the Longmogou diabase might have formed in a continental back-arc spreading environment of Longmucuo-Shuanghu ocean subduction.
The Duocai area is located in the northeastern margin of the Qiangtang terrane.In this area,Permian to Triassic magmatic rocks are widespread because of the subduction of Palaeo-Tethyan oceans and the final closure.We take the Longmogou diabase as the research object,and details the researches on its zircon U-Pb geochronology.The result shows that the diabase has crystalline age of(248.3±2.6)Ma and thus constrains its formation time to the Early Triassic.Cosidering previously published data,we suggest that the Longmogou diabase might have formed in a continental back-arc spreading environment of Longmucuo-Shuanghu ocean subduction.
引文
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[26]刘银.当江-多彩俯冲型蛇绿岩及其岩浆弧特征[D].北京:中国地质大学(北京),2011.
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[29]王召林.三江北段玉树地区复合造山与成矿作用研究[D].北京:中国地质科学院,2009.
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[32]Corfu F,Hanchar J M,Hoskin P W O,et al.Atlas of zircon textures[J].Reviews in Mineralogy and Geochemistry,2003,53(1):469-499.
[33]Griffin W L,Belousova E A,Shee S R,et al.Archean crustal evolution in the northern Yilgarn Craton:U-Pb and Hf-isotope evidence from detrital zircons[J].Precambrian Research,2004,131(3/4):231-282.
[34]何世平,李荣社,王超,等.青藏高原北羌塘昌都地块发现约4.0Ga碎屑锆石[J].科学通报,2011,56(8):573-582.
[35]刘彬.青藏高原中部玉树二叠纪-三叠纪镁铁质岩石的成因及其地球动力学背景[D].武汉:中国地质大学(武汉),2014.
[36]Yang T N,Zhang H R,Liu Y X,et al.Permo-Triassic arc magmatism in central Tibet:Evidence from zircon U-Pb geochronology,Hf isotopes,rare earth elements,and bulk geochemistry[J].Chemical Geology,2011,284(3):270-282.
[37]Yang T N,Ding Y,Zhang H R,et al.Two-phase subduction and subsequent collision defines the Paleotethyan tectonics of the southeastern Tibetan Plateau:Evidence from zircon U-Pb dating,geochemistry,and structural geology of the Sanjiang orogenic belt,southwest China[J].Geological Society of America Bulletin,2014,126(11/12):1654-1682.
[38]闫全人,王宗起,刘树文,等.西南三江特提斯洋扩张与晚古生代东冈瓦纳裂解:来自甘孜蛇绿岩辉长岩的SHRIMP年代学证据[J].科学通报,2005,50(2):158-166.
[39]Reid A,Wilson C J L,Shun L,et al.Mesozoic plutons of the Yidun Arc,SW China:U/Pb geochronology and Hf isotopic signature[J].Ore Geology Reviews,2007,31(1/4):88-106.
[40]Chen J L,Xu J F,Ren J B,et al.Geochronology and geochemical characteristics of Late Triassic porphyritic rocks from the Zhongdian arc,eastern Tibet,and their tectonic and metallogenic implications[J].Gondwana Research,2014,26(2):492-504.
[41]Wang B Q,Zhou M F,Li J W,et al.Late Triassic porphyritic intrusions and associated volcanic rocks from the Shangri-La region,Yidun terrane,Eastern Tibetan Plateau:Adakitic magmatism and porphyry copper mineralization[J].Lithos,2011,127(1/2):24-38.
[42]李善平,陈有顺,李伍福,等.青藏高原北羌塘盆地查涌蛇绿岩的地球化学特征及其构造意义[J].现代地质,2009,23(6):1030-1038.
[43]Scott R B,Kroenke L.Periodicity of remnant arcs and back-arc basins of the South Philippine Sea[J].Oceanologica Acta,1981,4:193-202.
[44]王毅智,祁生胜,安守文,等.青海南部杂多地区超镁铁质-镁铁质岩石的特征及Ar-Ar定年[J].地质通报,2007,26(6):668-674.
[2]Wang Q,Li Z X,Chung S L,et al.Late Triassic high-Mg andesite/dacite suites from northern Hohxil,North Tibet:Geochronology,geochemical characteristics,petrogenetic processes and tectonic implications[J].Lithos,2011,126(1):54-67.
[3]Wang B Q,Zhou M F,Chen W T,et al.Petrogenesis and tectonic implications of the Triassic volcanic rocks in the northern Yidun Terrane,Eastern Tibet[J].Lithos,2013,175/176(8):285-301.
[4]Zhai Q G,Jahn B M,Wang J,et al.The Carboniferous ophiolite in the middle of the Qiangtang terrane,Northern Tibet:SHRIMP U-Pb dating,geochemical and Sr-Nd-Hf isotopic characteristics[J].Lithos,2013,168/169(3):186-199.
[5]许志琴,杨经绥,李文昌,等.青藏高原中的古特提斯体制与增生造山作用[J].岩石学报,2013,29(6):1847-1860.
[6]Metcalfe I.Gondwana dispersion and Asian accretion:Tectonic and palaeogeographic evolution of eastern Tethys[J].Journal of Asian Earth Sciences,2013,66:1-33.
[7]李才.龙木错-双湖-澜沧江板块缝合带与石炭二叠纪冈瓦纳北界[J].吉林大学学报:地球科学版,1987,17(2):37-48.
[8]许伟,李才,江庆源,等.藏北羌塘中部冈玛错-日湾茶卡地区下石炭统望果山组的建立及其地质意义[J].地质通报,2014,33(11):1696-1701.
[9]江庆源,李才,解超明,等.藏北羌塘冈玛错地区望果山组火山岩地球化学特征及LA-ICP-MS锆石U-Pb年龄[J].地质通报,2014,33(11):1702-1714.
[10]Jiang Q Y,Li C,Su L,et al.Carboniferous arc magmatism in the Qiangtang area,northern Tibet:Zircon U-Pb ages,geochemical and Lu-Hf isotopic characteristics,and tectonic implications[J].Journal of Asian Earth Sciences,2015,100:132-144.
[11]Wang B,Wang L,Chen J,et al.Petrogenesis of Late DevonianEarly Carboniferous volcanic rocks in northern Tibet:New constraints on the Paleozoic tectonic evolution of the Tethyan Ocean[J].Gondwana Research,2015,66(6):323-339.
[12]吴浩.青藏高原羌塘中部375~200 Ma多期次岩浆作用[D].吉林:吉林大学,2016.
[13]Yang T N,Hou Z Q,Wang Y,et al.Late Paleozoic to Early Mesozoic tectonic evolution of northeast Tibet:Evidence from the Triassic composite western Jinsha-Garzê-Litang suture[J].Tectonics,2012,31(4):TC4004.
[14]Zhao S Q,Tan J,Wei J H,et al.Late Triassic Batang Group arc volcanic rocks in the northeastern margin of Qiangtang terrane,northern Tibet:Partial melting of juvenile crust and implications for Paleo-Tethys ocean subduction[J].International Journal of Earth Sciences,2015,104(2):369-387.
[15]赵少卿,付乐兵,魏俊浩,等.青海治多地区晚三叠世石英闪长岩地球化学特征及成岩动力学背景[J].地球科学:中国地质大学学报,2015,40(1):61-76.
[16]王凤林,魏俊浩,张玉洁,等.青海治多县多彩地区巴塘群英安岩锆石U-Pb年代学及其地质意义[J].地质科技情报,2017,36(1):26-32.
[17]刘彬,马昌前,黄坚,等.北羌塘北缘玉树三叠纪火山岩的成因机制及其构造意义[J].岩石矿物学杂志,2016,35(1):1-15.
[18]Halls H C.The importance and potential of mafic dyke swarms in studies of geodynamic processes[J].Geoscience Canada,1982,9(3):145-154.
[19]Yin A,Harrison T M.Geologic evolution of the Himalayan-Tibetan Orogen[J].Annual Review of Earth and Planetary Sciences,2000,28(28):211-280.
[20]Zhang Z M,Dong X,Santosh M,et al.Metamorphism and tectonic evolution of the Lhasa terrane,Central Tibet[J].Gondwana Research,2014,25(1):170-189.
[21]Kapp P,Yin A,Manning C E,et al.Tectonic evolution of the Early Mesozoic blueschist-bearing Qiangtang metamorphic belt,central Tibet[J].Tectonics,2003,22(4):11-17.
[22]Zhai Q G,Zhang R Y,Jahn B M,et al.Triassic eclogites from central Qiangtang,northern Tibet,China:Petrology,geochronology and metamorphic P-T path[J].Lithos,2011,125(1/2):173-189.
[23]Liu B,Ma C Q,Guo Y H,et al.Petrogenesis and tectonic implications of Triassic mafic complexes with MORB/OIB affinities from the western Garzê-Litang ophiolitic mélange,central Tibetan Plateau[J].Lithos,2016,260(1):253-267.
[24]Liu B,Ma C Q,Guo P,et al.Evaluation of late Permian mafic magmatism in the central Tibetan Plateau as a response to plume-subduction interaction[J].Lithos,2016,264(1):1-16.
[25]金贵善.西金乌兰-金沙江缝合带西段部分岩浆岩地质年代学及地球化学特征[D].北京:中国地质科学院,2006.
[26]刘银.当江-多彩俯冲型蛇绿岩及其岩浆弧特征[D].北京:中国地质大学(北京),2011.
[27]Chung S L,Chu M F,Zhang Y,et al.Tibetan tectonic evolution inferred from spatial and temporal variations in post-collisional magmatism[J].Earth-Science Reviews,2005,68(3/4):173-196.
[28]王毅智,刘生军,祁生胜,等.中华人民共和国区域地质调查报告(1∶250 000治多县幅I46C003004)[M].武汉:中国地质大学出版社,2014.
[29]王召林.三江北段玉树地区复合造山与成矿作用研究[D].北京:中国地质科学院,2009.
[30]Jackson S E,Pearson N J,Griffin W L,et al.The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology[J].Chemical Geology,2004,211(1/2):47-69.
[31]Black L P,Kamo S L,Williams I S,et al.The application of SHRIMP to Phanerozoic geochronology:A critical appraisal of four zircon standards[J].Chemical Geology,2003,200(1/2):171-188.
[32]Corfu F,Hanchar J M,Hoskin P W O,et al.Atlas of zircon textures[J].Reviews in Mineralogy and Geochemistry,2003,53(1):469-499.
[33]Griffin W L,Belousova E A,Shee S R,et al.Archean crustal evolution in the northern Yilgarn Craton:U-Pb and Hf-isotope evidence from detrital zircons[J].Precambrian Research,2004,131(3/4):231-282.
[34]何世平,李荣社,王超,等.青藏高原北羌塘昌都地块发现约4.0Ga碎屑锆石[J].科学通报,2011,56(8):573-582.
[35]刘彬.青藏高原中部玉树二叠纪-三叠纪镁铁质岩石的成因及其地球动力学背景[D].武汉:中国地质大学(武汉),2014.
[36]Yang T N,Zhang H R,Liu Y X,et al.Permo-Triassic arc magmatism in central Tibet:Evidence from zircon U-Pb geochronology,Hf isotopes,rare earth elements,and bulk geochemistry[J].Chemical Geology,2011,284(3):270-282.
[37]Yang T N,Ding Y,Zhang H R,et al.Two-phase subduction and subsequent collision defines the Paleotethyan tectonics of the southeastern Tibetan Plateau:Evidence from zircon U-Pb dating,geochemistry,and structural geology of the Sanjiang orogenic belt,southwest China[J].Geological Society of America Bulletin,2014,126(11/12):1654-1682.
[38]闫全人,王宗起,刘树文,等.西南三江特提斯洋扩张与晚古生代东冈瓦纳裂解:来自甘孜蛇绿岩辉长岩的SHRIMP年代学证据[J].科学通报,2005,50(2):158-166.
[39]Reid A,Wilson C J L,Shun L,et al.Mesozoic plutons of the Yidun Arc,SW China:U/Pb geochronology and Hf isotopic signature[J].Ore Geology Reviews,2007,31(1/4):88-106.
[40]Chen J L,Xu J F,Ren J B,et al.Geochronology and geochemical characteristics of Late Triassic porphyritic rocks from the Zhongdian arc,eastern Tibet,and their tectonic and metallogenic implications[J].Gondwana Research,2014,26(2):492-504.
[41]Wang B Q,Zhou M F,Li J W,et al.Late Triassic porphyritic intrusions and associated volcanic rocks from the Shangri-La region,Yidun terrane,Eastern Tibetan Plateau:Adakitic magmatism and porphyry copper mineralization[J].Lithos,2011,127(1/2):24-38.
[42]李善平,陈有顺,李伍福,等.青藏高原北羌塘盆地查涌蛇绿岩的地球化学特征及其构造意义[J].现代地质,2009,23(6):1030-1038.
[43]Scott R B,Kroenke L.Periodicity of remnant arcs and back-arc basins of the South Philippine Sea[J].Oceanologica Acta,1981,4:193-202.
[44]王毅智,祁生胜,安守文,等.青海南部杂多地区超镁铁质-镁铁质岩石的特征及Ar-Ar定年[J].地质通报,2007,26(6):668-674.