LA-ICP-MS Zircon U-Pb Ages of the Zhahe Pluton in North Part of Sanjiang Orogenic Belt and Its Geological Significance
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摘要: 扎河岩体产出于三江造山带北段可可西里-金沙江缝合带，呈北西向展布，受北西向断裂构造控制。笔者通过详细调查，在石英闪长岩锆石中获得的（190.4±2.8）Ma的年龄值，在富石英英云闪长岩锆石中获得的（192.1±1.2）Ma的年龄值，基本反映了扎河岩体成岩于早侏罗世，表明金沙江结合带经受了该时期构造-岩浆活动的影响。稀土元素特征表明该套侵入岩属轻稀土富集、重稀土平坦型，具有弱正Eu异常，反映岩石经历了一定程度的分离结晶作用，微量元素显示出活动大陆边缘岛弧岩浆的特征，笔者通过野外地质调查，结合区域构造演化，认为侏罗纪早期三江北段已进入碰撞后陆内汇聚阶段，该期构造-岩浆事件的发生是受班公湖-怒江洋向北俯冲消减持续影响效应的产物。
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关键词:
- 造山带 /
- 扎河岩体 /
- 锆石LA-ICP-MS U-Pb年龄 /
- 地球化学
Abstract: The Zhahe pluton is located in the north part of the Sanjiang Orogenic Belt, with NW trend, which is controlled by NE direction fault. According to the detailed survey, the obtained zircon U-Pb ages of quartz diorite and tonalite are (190.4±2.8) Ma and (192.1±1.2) Ma, respectively, indicating that the Zhahe pluton was formed in Early Jurassic. The dating result suggests that the Jinshajiang suture zone was affected by the tectonic-magmatic activity in this period. On the chondrite-normalized REE diagram, this pluton is enriched in LREE and has a flat HREE pattern. The slight negative anomaly of Eu indicates that this pluton experienced a fractional crystallization of plagioclase. The trace element distribution of this pluton is similar to the ones of island arc magma.Based on the geochemistry and petrography characteristics mentioned above, it's concluded that the Zhahe Pluton has affected by the subduction component and it might be formed in a tectonic compression island arc or active continental margin.After analyzing the field geological survey and regional tectonic evolution, it's believed that the north part of Sanjiang Orogenic Belt had entered the stage of intracontinental convergence in Early Jurassic Period, and that this tectono-magmatic event has affected by the northwardsubduction of Bangong Lake-Nujiang Ocean and serves as the product of this sustained tectonic effect.-
Keywords:
- orogenic belt /
- the Zhahe pluton /
- Zircon U-Pb age /
- geochemistry
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侯增谦,王二七,莫宣学,等.青藏高原碰撞造山与成矿作用[M].北京:地质出版社,2008. HOU Zengqian,WANG Erqi,MO Xuanxue,et al.Collisionalorogenyandmetallogenesisof the Tibetanplateau[M].Beijing:Geological Publishing House,2008(in Chinese with English abstract).
刘增乾,李兴振,叶庆同,等.三江地区构造岩浆带的划分与矿产分布规律[M].北京:地质出版社,1993. LIU Zengqian,LI Xingzhen,YE Qingtong,et al.Division of Tectona-Magmaticzones and the Distrbution of deposits in the Sanjiang Area[M].Beijing:Geological Publishing House,1993 (in Chinese with English abstract).
莫宣学,潘桂棠.从特提斯到青藏高原形成:构造-岩浆事件的约束[J].地学前缘,2006,13 (6):43-51. MO Xuanxue,PAN Guidang.From the Tethysto the formation of the Qinghai-Tibet Plateau:constrained by tectono-magmaticevents[J]. Earth Science Frontiers,2006,3(6):43-51(in Chinese with English abstract).
陈建平,郝金华.青海南部三江北段铜多金属成矿系统演化研究[J].西北地质,2012,45 (1):236-243. CHEN Jianping,HAO Jinhua.Study on the evolution of copper polymetallicmetallogenic system in sanjiang north of qinghai[J].Northwestern Geology,2012,45 (1):236-243.
陈向阳,粟亚芝,张雨莲,等.三江北段纳日贡玛斜长花岗斑岩的年代学及地质意义[J].西北地质,2013,46(4):49-56. CHEN Xiangyang,SU Yazhi,ZHANG Yulian,et al.The chronology and geological significance of the Narigongmaplagioclast porphyry in the north section of sanjiang[J].Northwestern Geology,2013,46 (4):49-56.
宋忠宝,贾群子,张雨莲,等.三江北段纳日贡玛黑云母花岗斑岩LA-ICP-MS锆石U-Pb定年及地质意义[J].地质学报,2012,31(2-3):440-447. SONG Zhongbao,JIA Qunzi,ZHANG Yulian,et al.The chronology and geological significance of the NarigongmaBiotite porphyry LA-ICP-MS zirconU-Pb in the north section of sanjiang[J].Acta Geologica Sinica,2012,31(2-3):440-447.
李洁,陈文,雍拥,等.青海玉树地区扎喜科岩体形成时代、地球化学特征及构造意义研究[J].地球学报,2012,33(5):773-786. LI Jie,CHEN Wen,YONG Yong,et al.The geochemical characteristics and tectonic significance of Zhaxike rock mass formation in yushu area of qinghai province were studied[J]. Acta Geoscientia Sinica,2012,33(5):773-786.
段其发,王建雄,白云山,等.青海南部蛇绿岩中辉长岩锆石SHRIMP U-Pb定年和岩石地球化学特征[J].中国地质,2009,36(2):291-299. DUAN Qifa,WANG Jianxiong,BAI Yunshan,et al.The annual and rocky geochemical characteristics of the gabbro in ophiolite in southern qinghai province[J].Geology of China,2009,36(2):291-299.
白云山,段其发,牛志军,等.青海南部曲麻莱县达考岩体地球化学特征及其构造环境[J].华南地质与矿产,2012,28(01):12-19. BAI Yunshan,DUAN Qifa,NIU Zhijun,et al.Southern Qinghai Qumalai of test rock geochemical characteristics and tectonic environment[J],Geology and Mineral Resources of South China,2012,28(01):12-19.
李昌年.火山岩微量元素岩石学[M].武汉:中国地质大学出版社,1992:1-157. LI Changnian.Trace elements in volcanic rocks[M].Wuhan:China University of Geosciences Press,1992:1-157.
潘桂棠,陈智梁,李兴振,等.东特提斯地质构造形成演化[M].北京:地质出版社,1997:122-128. PAN Guitang,CHEN Zhiliang,LI Xingzhen,et al.The evolution of the geological structure in eastern Tethys[M].Geological Publishing House,1997:122-128.
吴福元,李献华,杨进辉,等.花岗岩成因研究的若干问题[J].岩石学报,2007,23(06):1217-1238. WU Fuyuan,LI Xianhua,YANG Jinhui,et al.Issues of granite genesis[J].Acte Petrologic Sinica,2007,23(06):1217-1238.
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].科学通报,2004,49(16):1589-1604. WU Yuangbao,ZHENG Yongfei.Zircon Minerageny Its interpretation of U-Pb age constraints[J].Acte Science Sinica,2004,49(16):1589-1604.
张旗,王焰,李承东,等.花岗岩的Sr-Yb分类及其地质意义[J].岩石学报,2006,22(09):2249-2269. ZHANG Qi,WANG Yan,LI Chengdong,et al.Sr-Yb granite classification and geological significance[J].Acte Petrologic Sinica,2006,22(09):2249-2269.
王毅智,刘生军,祁生胜,等.1:25万治多县幅区调报告[R].青海:青海省地质调查院,2006. WANG Yizhi,LIU Shengjun,QI Shengshen,et al.1:250000 regional geological survey report Zhiduo County Sheet[R].Qinghai:Qinghai Geological Survey Institute,2006.
段其发,牛志军,白云山,等.1:25万曲麻莱县幅区调报告[R].湖北:宜昌地质矿产研究所,2006. DUAN Qifa,NIU Zhijun BAI Yunshan et al.1:250000 regional geological survey reportQumalaiCounty Sheet[R].Hubei:Yichang Geological and Mineral Research Institute,2006.
BATCHELORR A. BOWDEN P. Petrogenetic interpretation of granitoid rock series using multicationic parameters[J].Chemical Geology,1985,48(1-4):43-55.
GREEN TH. Significance of Nb/Ta as an indicator of geochemical P rocesses in the crust-mantle system[J].Chemical Geology,1995,120(3-4):347-359.
PEIVE AB.the foming of european continental crust[J].Geotectonics,1975,(5):6-24.
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