大别造山带岳西地区岩脉群锆石定年及意义
|
摘要
大别造山带岳西地区分布有大量NNE走向的岩脉,其岩石类型多样,包括石英正长斑岩、花岗斑岩、石英闪长岩以及辉绿岩等。区内广泛发育中生代岩浆岩,以中酸性为主,伴有少量的基性岩。岩脉切穿区内广泛发育的岩浆岩,为燕山期岩浆活动最晚的产物。通过锆石LA-ICPMS定年方法得到石英正长斑岩、石英闪长岩和花岗斑岩3种类型的三件岩脉样品的年龄分别为127.1 Ma±4.5 Ma,127.5 Ma±1.9 Ma和127.4 Ma±2.5 Ma,这些岩脉的形成时代较为集中,其形成时代为早白垩世,代表了岳西地区中生代岩浆活动幕的结束。岳西地区岩脉群是郯庐断裂带左行走滑动力学体制下,岩浆沿剪张裂隙侵入形成,岩脉的形成时代指示郯庐断裂带南段中生代第三次左行走滑可能发生在127 Ma左右。
NNE-striking dike swarm is widespread in Yuexi area of the Dabie orogen and these dikes consist of different rock types,including quartz-syenite porphyry,granite porphyry,quartzdiorite and diabase.It shows that the dikes cut through the Yanshanian intrusive bodies,indicating that the dikes formed in the latest stage of Yanshanian magmatic activity.LA-ICPMS zircon U-Pb dating yields weighted mean ages of 127.1Ma±4.5Ma,127.5Ma±1.9Ma and 127.4Ma±2.5Ma for the quartz-syenite porphyry,quartz-diorite and granite porphyry,respectively.Therefore,these dikes are generated during a short time span and formed in the early Cretaceous,representing the termination of Mesozoic magmatism in this region.Owing to the sinistral strike-slip movement of the Tan-Lu fault zone,the dike swarm in Yuexi area intruded along the shear-tensile cracks.The ages of these dikes indicate that the third sinistral strike-slip movement of the TLFZ might take place around 127 Ma.
NNE-striking dike swarm is widespread in Yuexi area of the Dabie orogen and these dikes consist of different rock types,including quartz-syenite porphyry,granite porphyry,quartzdiorite and diabase.It shows that the dikes cut through the Yanshanian intrusive bodies,indicating that the dikes formed in the latest stage of Yanshanian magmatic activity.LA-ICPMS zircon U-Pb dating yields weighted mean ages of 127.1Ma±4.5Ma,127.5Ma±1.9Ma and 127.4Ma±2.5Ma for the quartz-syenite porphyry,quartz-diorite and granite porphyry,respectively.Therefore,these dikes are generated during a short time span and formed in the early Cretaceous,representing the termination of Mesozoic magmatism in this region.Owing to the sinistral strike-slip movement of the Tan-Lu fault zone,the dike swarm in Yuexi area intruded along the shear-tensile cracks.The ages of these dikes indicate that the third sinistral strike-slip movement of the TLFZ might take place around 127 Ma.
引文
[1]刘晓强,闫峻,王爱国,等.大别造山带岳西地区中生代岩浆岩年代学研究[J].地质论评,2016,62(4):897-914.
[2]Xu H J,Ma C Q,Ye K.Early cretaceous granitoids and their implications for the collapse of the Dabie orogen,eastern China:SHRIMP zircon U-Pb dating and geochemistry[J].Chemical Geology,2007,240:238-259.
[3]续海金,叶凯,马昌前.北大别早白垩世花岗岩类的Sm-Nd和锆石Hf同位素及其构造意义[J].岩石学报,2008,24(1):87-103.
[4]朱光,宋传中,王道轩,等.郯庐断裂带走滑时代的40 Ar/39 Ar年代学研究及其构造意义[J].中国科学(D辑),2001,31(3):250-256.
[5]韩雨,牛漫兰,朱光,等.郯庐断裂带肥东段早白垩世中期走滑运动的年代学证据[J].地球科学进展,2015,30(8):922-939.
[6]Zheng Y F,Wu Y B,Zhao Z F,et al.Metamorphic effect on zircon Lu-Hf and U-Pb isotope systems in ultrahigh-pressure eclogite-facies metagranite and metabasite[J].Earth and Planetary Science Letters,2005,240:378-400.
[7]Liu Y C,Li S G,Xu S T.Zircon SHRIMP U-Pb dating for gneisses in northern Dabie high T/P metamorphic zone,central China:Implications for decoupling within subducted continental crust[J].Lithos,2007,96(1):170-185.
[8]Zhao Z F,Zheng Y F,Wei C S,et al.Zircon U-Pb ages,Hf and O isotopes constrain the architecture of the ultrahigh-pressure Dabie orogen in China[J].Chemical Geology,2008,253(3/4):222-242.
[9]Zheng Y F,Zhao Z F,Wu Y B,et al.Zircon U-Pb age,Hf and O isotope constraints on protolith origin of ultrahigh-pressure eclogite and gneiss in the Dabie orogen[J].Chemical Geology,2006,231:135-158.
[10]Xu S T,Liu Y C,Su W,et al.Discovery of the eclogite and its petrography in the Northern Dabie Mountains[J].Chinese Science Bulletin,2000,45(3):273-278.
[11]Xu S T,Liu Y C,Jiang L L,et al.Architecture and kinematics of the Dabie Mountains orogen[M].University of Science and Technology of China Press Hefei,2002,1-133.
[12]Xue F,Rowley D B,Tucker R D,et al.U-Pb zircon ages of granitoid rocks in the north Dabie complex,eastern Dabie Shan,China[J].Journal of Geology,1997,105:744-753.
[13]Hacker B R,Ratschbacher L,Webb L,et al.U-Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie Orogen,China[J].Earth and Planetary Science Letters,1998,161:215-230.
[14]金成伟,郑祥身.大别岳西地区花岗岩类岩石学及其成因[J].岩石学报,1998,14(4):493-502.
[15]闫峻,彭戈,刘建敏,等.下扬子繁昌地区花岗岩成因:锆石年代学和Hf-O同位素制约[J].岩石学报,2012,28(10):588-597.
[16]Zheng Y F,Wu Y B,Chen F C,et al.Zircon U-Pb and oxygen isotope evidence for a large-scale 18 O depletion event in igneous rocks during the Neoproterozoic[J].Geochimica et Cosmochimica Acta,2004,68(20):4 145-4 165.
[17]吴元保,陈道公,夏群科,等.北大别黄土岭麻粒岩锆石U-Pb离子探针定年[J].岩石学报,2002,18(3):378-382.
[18]Wu Y B,Chen D G,Xia Q K,et al.In-situ trace element analyses and Pb-Pb dating of zircons in granulite from Huangtuling,Dabieshan by LA-ICP-MS[J].Science China Earth Sciences,2003,46(11):1 161-1 170.
[19]赵子福,郑永飞.俯冲大陆岩石圈重熔:大别-苏鲁造山带中生代岩浆岩成因[J].中国科学(D辑),2009,39(7):888-909.
[20]朱光,王薇,顾承串,等.郯庐断裂带晚中生代演化历史及其对华北克拉通破坏过程的指示[J].岩石学报,2016,32(4):935-949.
[21]Zhu G,Wang Y S,Liu G S,et al.40 Ar/39 Ar dating of strike-slip motion on the Tan-Lu fault zone,East China[J].Journal of Structural Geology,2005,27(8):1 379-1 398.
[22]Zhu G,Wang Y.Sinistral to Normal Faulting along the Tan-Lu Fault Zone:Evidence for Geodynamic Switching of the East China Continental Margin[J].Journal of Geology,2010,2(118):277-293.
[23]张岳桥,董树文.郯庐断裂带中生代构造演化史:进展与新认识[J].地质通报,2008,27(9):1 371-1 390.
[24]王微,宋传中,李加好,等.郯庐断裂带肥东段剪切活动锆石U-Pb测年[J].地质科学,2015,50(3):588-597.
[2]Xu H J,Ma C Q,Ye K.Early cretaceous granitoids and their implications for the collapse of the Dabie orogen,eastern China:SHRIMP zircon U-Pb dating and geochemistry[J].Chemical Geology,2007,240:238-259.
[3]续海金,叶凯,马昌前.北大别早白垩世花岗岩类的Sm-Nd和锆石Hf同位素及其构造意义[J].岩石学报,2008,24(1):87-103.
[4]朱光,宋传中,王道轩,等.郯庐断裂带走滑时代的40 Ar/39 Ar年代学研究及其构造意义[J].中国科学(D辑),2001,31(3):250-256.
[5]韩雨,牛漫兰,朱光,等.郯庐断裂带肥东段早白垩世中期走滑运动的年代学证据[J].地球科学进展,2015,30(8):922-939.
[6]Zheng Y F,Wu Y B,Zhao Z F,et al.Metamorphic effect on zircon Lu-Hf and U-Pb isotope systems in ultrahigh-pressure eclogite-facies metagranite and metabasite[J].Earth and Planetary Science Letters,2005,240:378-400.
[7]Liu Y C,Li S G,Xu S T.Zircon SHRIMP U-Pb dating for gneisses in northern Dabie high T/P metamorphic zone,central China:Implications for decoupling within subducted continental crust[J].Lithos,2007,96(1):170-185.
[8]Zhao Z F,Zheng Y F,Wei C S,et al.Zircon U-Pb ages,Hf and O isotopes constrain the architecture of the ultrahigh-pressure Dabie orogen in China[J].Chemical Geology,2008,253(3/4):222-242.
[9]Zheng Y F,Zhao Z F,Wu Y B,et al.Zircon U-Pb age,Hf and O isotope constraints on protolith origin of ultrahigh-pressure eclogite and gneiss in the Dabie orogen[J].Chemical Geology,2006,231:135-158.
[10]Xu S T,Liu Y C,Su W,et al.Discovery of the eclogite and its petrography in the Northern Dabie Mountains[J].Chinese Science Bulletin,2000,45(3):273-278.
[11]Xu S T,Liu Y C,Jiang L L,et al.Architecture and kinematics of the Dabie Mountains orogen[M].University of Science and Technology of China Press Hefei,2002,1-133.
[12]Xue F,Rowley D B,Tucker R D,et al.U-Pb zircon ages of granitoid rocks in the north Dabie complex,eastern Dabie Shan,China[J].Journal of Geology,1997,105:744-753.
[13]Hacker B R,Ratschbacher L,Webb L,et al.U-Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie Orogen,China[J].Earth and Planetary Science Letters,1998,161:215-230.
[14]金成伟,郑祥身.大别岳西地区花岗岩类岩石学及其成因[J].岩石学报,1998,14(4):493-502.
[15]闫峻,彭戈,刘建敏,等.下扬子繁昌地区花岗岩成因:锆石年代学和Hf-O同位素制约[J].岩石学报,2012,28(10):588-597.
[16]Zheng Y F,Wu Y B,Chen F C,et al.Zircon U-Pb and oxygen isotope evidence for a large-scale 18 O depletion event in igneous rocks during the Neoproterozoic[J].Geochimica et Cosmochimica Acta,2004,68(20):4 145-4 165.
[17]吴元保,陈道公,夏群科,等.北大别黄土岭麻粒岩锆石U-Pb离子探针定年[J].岩石学报,2002,18(3):378-382.
[18]Wu Y B,Chen D G,Xia Q K,et al.In-situ trace element analyses and Pb-Pb dating of zircons in granulite from Huangtuling,Dabieshan by LA-ICP-MS[J].Science China Earth Sciences,2003,46(11):1 161-1 170.
[19]赵子福,郑永飞.俯冲大陆岩石圈重熔:大别-苏鲁造山带中生代岩浆岩成因[J].中国科学(D辑),2009,39(7):888-909.
[20]朱光,王薇,顾承串,等.郯庐断裂带晚中生代演化历史及其对华北克拉通破坏过程的指示[J].岩石学报,2016,32(4):935-949.
[21]Zhu G,Wang Y S,Liu G S,et al.40 Ar/39 Ar dating of strike-slip motion on the Tan-Lu fault zone,East China[J].Journal of Structural Geology,2005,27(8):1 379-1 398.
[22]Zhu G,Wang Y.Sinistral to Normal Faulting along the Tan-Lu Fault Zone:Evidence for Geodynamic Switching of the East China Continental Margin[J].Journal of Geology,2010,2(118):277-293.
[23]张岳桥,董树文.郯庐断裂带中生代构造演化史:进展与新认识[J].地质通报,2008,27(9):1 371-1 390.
[24]王微,宋传中,李加好,等.郯庐断裂带肥东段剪切活动锆石U-Pb测年[J].地质科学,2015,50(3):588-597.