地学前缘 ›› 2019, Vol. 26 ›› Issue (5): 206-221.DOI: 10.13745/j.esf.sf.2019.9.17

• 岩浆过程与成矿 • 上一篇    下一篇

华北克拉通南缘崤山地区后河岩体锆石U-Pb年代学、地球化学特征及对区域成矿潜力的启示

齐楠,陈衍景,王玭,吴艳爽,许晨,展恩鹏   

  1. 1. 北京大学 造山带与地壳演化重点实验室, 北京 100871
    2. 中国科学院 边缘海与大洋地质重点实验室; 中国科学院 南海海洋研究所, 广东 广州 510301
    3. 中国科学院 新疆生态与地理研究所, 新疆 乌鲁木齐 830011
  • 收稿日期:2019-02-28 修回日期:2019-06-25 出版日期:2019-09-28 发布日期:2019-09-28
  • 通讯作者: 王玭(1987—),女,博士,矿物学、岩石学、矿床学专业。
  • 作者简介:齐楠(1994—),女,博士研究生,矿物学、岩石学、矿床学。E-mail:q497921730@126.com
  • 基金资助:
    国家自然科学基金项目(41630313,41602065)

Zircon U-Pb geochronology and geochemistry of Houhe granite in the Xiaoshan area, southern North China Craton and their implication for regional metallogenic potential

QI Nan,CHEN Yanjing,WANG Pin,WU Yanshuang,XU Chen,ZHAN Enpeng   

  1. 1. Key Laboratory of Orogenic Belt and Crustal Evolution, Peking University, Beijing 100871, China
    2. Key Laboratory of Ocean and Marginal Sea Geology, Chinese Academy of Sciences; South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
    3. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, rümqi 830011, China
  • Received:2019-02-28 Revised:2019-06-25 Online:2019-09-28 Published:2019-09-28
  • Supported by:
     

摘要: 后河岩体位于华北克拉通南缘崤山北部,岩体侵位于太古宙太华超群地层中,主要岩性是黑云母石英二长岩和黑云母二长花岗岩。黑云母石英二长岩和黑云母二长花岗岩的锆石U-Pb年龄分别为(131.0±1.8) Ma和(127.3±1.0) Ma。地球化学特征表明二者均具有富钾(K2O/Na2O =1.00~1.51)、过铝(A/CNK =1.12~1.17)、贫镁(Mg#=26~34)的特征,属高钾钙碱性系列的过铝质花岗岩。轻重稀土元素分馏程度较高,富集轻稀土,亏损重稀土,总体富集大离子亲石元素(LILE)而亏损高场强元素(HFSE),Eu异常不明显(δEu=0.84~0.97),(La/Yb)N比值高。Hf同位素特征显示,εHf(t)具有明显的负值(-17.8~-9.5),TDM2主要集中在2.3~1.7 Ga。综上所述,早白垩世后河岩体是华北克拉通南缘加厚下地壳部分熔融的产物,形成于地壳由挤压加厚向伸展减薄转换的阶段。

 

关键词: 后河岩体, 崤山, 锆石U-Pb年龄, 锆石铪同位素, 地球化学

Abstract: The Houhe granitiod is located in the northern Xiaoshan area, southern North China Craton, intruding into the Archean Taihua Group. It mainly consists of biotite-quartz monzonite and biotite-monzogranite, with LA-ICP-MS zircon U-Pb ages of 127.9±1.4 and 131.0±1.8 Ma, respectively. The geochemical and isotopic data show that the two types of granites are similar geochemically—they are both peraluminous high-K calc-alkaline rocks, having high K2O (K2O/Na2O =1.001.51) and Al2O3 (A/CNK=1.121.17) and low MgO (Mg#=2634) contents. They are enriched in Ba, K, U, Th, Pb and light rare earth elements and depleted in high field strength (eg. Nb, Ta and Ti) and heavy rare earth elements, with nearly no Eu anomalies (δEu=0.840.97) and high Sr/Y and (La/Yb)N ratios. Isotopic analysis of zircons from the granite yielded εHf(t) value of -17.8 to -9.5 and TDM2(Hf) ages of 2.31.7 Ga. In conclusion, the Houhe granite originated primarily from partial melting of thickened continental crust, as tectonic settings transferred from post-collisional to intraplate anorogenic dynamics at the southern margin of the North China Craton.

Key words: Houhe granite, Xiaoshan, zircon U-Pb age, zircon Hf isotope, geochemistry

中图分类号: