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现代地质 ›› 2019, Vol. 33 ›› Issue (03): 501-513.DOI: 10.19657/j.geoscience.1000-8527.2019.03.04

• 矿床学与岩石学 • 上一篇    下一篇

新疆巴音布鲁克地区奥陶纪侵入岩地球化学特征及其构造意义

刘祥1(), 弓小平1, 刘洋洋1, 王哲2, 凤骏2, 刘世杰1, 韩秉峻1, 齐锐1   

  1. 1.新疆大学 地质与矿业工程学院,新疆 乌鲁木齐 830047
    2.新疆维吾尔自治区地质调查院,新疆 乌鲁木齐 830000
  • 收稿日期:2018-01-11 修回日期:2018-12-08 出版日期:2019-06-23 发布日期:2019-06-24
  • 通讯作者: 弓小平
  • 作者简介:弓小平,男,教授级高级工程师,博士,1963年出生,地球探测与信息技术专业,主要从事综合信息成矿预测。Email: gxiaoping01@163.com
    刘 祥,男,硕士研究生,1993年出生,地质工程专业,主要从事成矿预测研究。Email: 1064755273@qq.com
  • 基金资助:
    国家自然科学基金项目“新疆东准噶尔卡拉麦里金矿带成矿流体特征及其与侵入体的关系研究”(41462004);中国地质调查局大调查项目“新疆巴伦台1∶5万K45E006010、K45E007010、K45E007011、K45E008010、K45E008011五幅区域地质调查”(1212011140058)

Geochemical Characteristics and Tectonic Significance of Ordovician Intrusions in Bayanbulak, Xinjiang,China

LIU Xiang1(), GONG Xiaoping1, LIU Yangyang1, WANG Zhe2, FENG Jun2, LIU Shijie1, HAN Bingjun1, QI Rui1   

  1. 1. College of Geology and Mining Engineering, Xinjiang University,Urumqi,Xinjiang 830047, China
    2. Geological Survey Institute of Xinjiang Uygur Autonomous Region,Urumqi,Xinjiang 830000, China
  • Received:2018-01-11 Revised:2018-12-08 Online:2019-06-23 Published:2019-06-24
  • Contact: GONG Xiaoping

摘要:

巴音布鲁克地区位于中天山地块中天山多期复合陆缘岩浆弧。通过研究发现,该地区奥陶纪侵入岩岩性主要为石英闪长岩、花岗闪长岩、二长花岗岩。通过锆石U-Pb定年识别出中奥陶世(462.7±6.2) Ma、(463.4±2.8) Ma、(471.5±5.9) Ma侵入体,岩石地球化学结果表明岩体具有准铝质钙碱性系列岩石特征。稀土元素配分型式呈明显的右倾模式,具负Eu异常,微量元素显示出大离子亲石元素富集、高场强元素亏损的配分模式。地球化学特征指示侵入体形成于俯冲碰撞环境,其岩浆来源为壳幔混源岩浆。综合分析认为,南天山洋盆初始向北发生俯冲作用的时间为中奥陶世早期,与俯冲过程中的右旋运动有关,岩浆活动在中天山地区显示出由西部逐步向东部扩展演化的规律。

关键词: 巴音布鲁克地区, 侵入岩, 奥陶纪, 壳幔混源, 南天山洋盆

Abstract:

The Bayinbuluk area is located in the multi-stage composite continental arc in the Middle Tianshan Complex. Our study found that the Ordovician intrusions include mainly quartz diorite, granodiorite and monzogranite. Zircon U-Pb dating yielded Middle Ordovician ages (462.7±6.2 Ma, 463.4±2.8 Ma, 471.5±5.9 Ma) intrusions, and geochemical analysis shows metaluminous and calc-alkaline affinities. Chondrite-normalized REE patterns show clear right-inclining pattern and negative Eu anomalies. Trace element analysis results show large ion lithophile element (LILE) enrichments and high field strength element (HFSE) depletions. Geochemical characteristics indicate that the intrusions were formed in a subduction-collisional setting, and the magma may have been derived from a crust-mantle mixed source. Comprehensive analysis suggests that the South Tianshan ocean basin started to subduct northward in the early Middle Ordovician, which may have been related to the regional dextral movement. Magmatism in the Middle Tianshan shows a gradual eastward migration and expansion.

Key words: Bayinbuluk area, intrusion, Ordovician, crust-mantle mixed source, South Tianshan ocean basin

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