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现代地质 ›› 2022, Vol. 36 ›› Issue (01): 282-294.DOI: 10.19657/j.geoscience.1000-8527.2021.046

• 岩石学 • 上一篇    下一篇

内蒙古浩布高铅锌矿床小罕山岩体年代学、Hf同位素及地球化学特征

周桐1,2,3(), 孙珍军1,2(), 于赫楠1,2, 王承洋1,2, 刘广虎1,2   

  1. 1. 防灾科技学院 地球科学学院,河北 三河 101601
    2. 河北省地震动力学重点实验室,河北 三河 101601
    3. 桂林理工大学 地球科学学院,广西 桂林 541004
  • 收稿日期:2020-11-20 修回日期:2021-11-10 出版日期:2022-02-10 发布日期:2022-03-08
  • 通讯作者: 孙珍军
  • 作者简介:孙珍军,男,副教授,1982年出生,矿物学、岩石学、矿床学专业,主要从事矿床地质学、矿床地球化学研究。Email: 306292193@qq.com
    周 桐,男,硕士研究生,1994年出生,矿物学、岩石学、矿床学专业,主要从事矿床地质学、矿床地球化学研究。Email: 2583831404@qq.com
  • 基金资助:
    中央高校基本科研业务费专项项目(ZY20215129);自然资源部东北亚矿产资源评价重点实验室开放基金“大兴安岭南段浩布高铅锌矿成矿流体演化过程研究”(DBY-KF-19-08);中国地质调查局重要锡、锰等矿集区矿产地质调查项目“内蒙古浩布高—榆树林—黄土梁锡多金属矿矿集区矿产调查”子项目“典型矿床研究”(WKZB1911BJM30071/008)

Zircon U-Pb Geochronology, Hf isotope and Whole-Rock Geochemical Characteristics of Xiaohanshan Pluton in Haobugao Pb-Zn Deposit, Inner Mongolia

ZHU Tong1,2,3(), SUN Zhenjun1,2(), YU Henan1,2, WANG Chengyang1,2, LIU Guanghu1,2   

  1. 1. School of Earth Science, China Institute of Disaster Prevention, Sanhe, Hebei 101601, China
    2. Hebei Key Laboratory of Earthquake Dynamics, Sanhe, Hebei 101601, China
    3. College of Earth Science, Guilin University of Technology, Guilin, Guangxi 541004, China
  • Received:2020-11-20 Revised:2021-11-10 Online:2022-02-10 Published:2022-03-08
  • Contact: SUN Zhenjun

摘要:

内蒙古赤峰浩布高铅锌矿床大地构造位置位于大兴安岭地区南段,属黄岗梁—甘珠尔庙褶皱成矿带。对浩布高铅锌矿床小罕山岩体进行了详细的岩石学、年代学、岩石地球化学和Hf同位素研究。结果显示:小罕山岩体主要岩石类型为二长花岗岩,形成于(143.9±1.1) Ma,属于早白垩世;地球化学组成上表现出高硅(SiO2=66.96%~68.05%)、富碱(Na2O+K2O=9.91%~10.09%)、弱铝(Al2O3=15.69%~16.49%)、低钙(CaO=1.22%~1.41%)及低TFe2O3/MgO值(平均值为8.29)的特征,属于准铝质到过铝质花岗岩;稀土元素配分曲线呈右倾轻稀土富集,δEu(0.33~0.41)表现为明显的负异常,总体表现出富集大离子亲石元素(Rb、K等元素)和不相容元素(Th、U等元素)、亏损高场强元素(Nb、P、Nb、Ta、Ti等元素)的特征,显示出A2型花岗岩属性。样品初始176Hf/177Hf值为0.282 829~0.282 936,平均值为0.282 888;εHf(t)范围在4.4~8.4之间,平均值为6.7,表明小罕山岩体主要源于中下地壳部分熔融,且有少量地幔物质加入。综合认为小罕山岩体的形成与早白垩世古太平洋板块俯冲大陆边缘的后碰撞伸展构造环境有关。

关键词: 地球化学, 锆石U-Pb定年, 早白垩世, 小罕山岩体, 浩布高铅锌矿床

Abstract:

The Haobugao lead-zinc deposit is tectonically located in the southern part of the Great Xing’an Range, and is part of the Huanggangliang-Ganzhuermiao tectono-metallogenic belt. In this paper, detailed data on petrology, U-Pb geochronology, geochemistry and Hf isotopes were presented on the Xiaohanshan pluton of the Haobugao lead-zinc deposit. The results show that the main rock type of the Xiaohanshan pluton is monzogranite, which was formed in the Early Cretaceous (143.9±1.1 Ma). The rocks have high SiO2 (66.96%-68.05%) and alkali (Na2O+K2O=9.91%-10.09%), but low Al2O3 (15.69%-16.49%), CaO (1.22%-1.41%), and TFe2O3/MgO (average 8.29). The rocks belong to metaluminous to peraluminous granites with right-inclining REE distribution patterns and distinct negative Eu anomalies (0.33-0.41). The samples also show enrichments in large ion lithophilic elements (LILEs, e.g., Rb, K) and other incompatible elements (e.g., Th, U), whereas high field strength elements (HFSEs, e.g., Nb, P, Nb, Ta, Ti) are depleted, showing A2-type granite affinity. The rocks have initial 176Hf/177Hf values of 0.282,829-0.282,936(average 0.282,888) and εHf(t) of 4.4 to 8.4 (average 6.7), indicating that the Xiaohanshan pluton is mainly derived from partial melting of the middle and lower crust with minor mantle material input. It is considered that formation of the Xiaohanshan pluton was related to the post-collision extensional tectonics in the Early Cretaceous Paleo-Pacific subduction continental margin.

Key words: geochemistry, zircon U-Pb dating, Early Cretaceous, Xiaohanshan pluton, Haobugao lead-zinc deposit

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