| 黑龙江多宝山地区裸河岩体锆石U-Pb年龄、地球化学特征及地质意义 |
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| 作者姓名： | 符安宗 李金明 吕石佳 石国明 |
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| 作者单位： | 黑龙江省自然资源调查院,黑龙江 哈尔滨 150036 |
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| 基金项目： | 中国地质调查局“黑龙江1∶5万三矿沟等六幅(三矿沟、三峰山、一六九幅、多宝山铜矿幅、星火公社幅、一五三幅)区域地质调查(编号: DD20160047-07)”项目资助 |
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| 摘 要： | 为加深对兴蒙造山带中段中生代构造演化的认识,探讨多宝山地区侏罗纪构造岩浆演化,选取位于大兴安岭与小兴安岭结合部的裸河岩体开展岩石学、年代学和地球化学研究。结果表明: 裸河岩体主要由中细粒和细粒花岗闪长岩组成,岩体中部发育少量花岗闪长斑岩,花岗闪长岩锆石U-Pb年龄为(168.09±0.95) Ma,形成于中侏罗世中期,该期花岗闪长岩的主量元素含量具有富Na、高K、低Ti、低P的特点,微量元素含量具有低Sr、高Yb的特点,重稀土亏损,具弱负Eu异常,属于高钾钙碱性系列I型花岗岩。构造环境判别图解指示裸河岩体花岗闪长岩应属后碰撞花岗岩。结合研究区周边早侏罗世—中侏罗世侵入岩体的特征,裸河岩体形成于蒙古—鄂霍茨克洋闭合后的后碰撞构造环境。
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| 关 键 词： | 中侏罗世 锆石U-Pb年龄 地球化学特征 I型花岗岩 裸河岩体 |
| 收稿时间： | 2021-04-06 |
Zircon U-Pb ages,geochemical characteristics and geological significance of Luohe pluton in Duobaoshan area,Heilongjiang Province |
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| Authors: | FU Anzong LI Jinming LV Shijia SHI Guoming |
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| Institution: | Heilongjiang Institute of Natural Resources Research, Heilongjiang Harbin 150036, China |
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| Abstract: | Petrology, geochronology and geochemistry of Luohe pluton in the connecting areas between Great Xinganling and Lesser Khingan Mountains were studied to intensify the knowledge of the tectonic evolution in the middle part of Xingmeng orogenic belt and discuss the Jurassic tectonomagmatic evolution in Duobaoshan area. The results show that Luohe pluton is mainly composed of medium fine-grained granodiorite and fine-grained granodiorite, with a small amount of granodiorite porphyry developed in the middle of the pluton. The zircon U-Pb ages of the granodiorite is (168.09 ± 0.95) Ma, indicating that it is emplaced during the Middle Jurassic. The granodiorite is characterized by high Na, high K, low Ti and low P in major elements, and low Sr and high Yb in trace elements, with depleted HREE. And weakly negative Eu anomaly is in REE distribution, which makes the granodiorite belonging to the high-K calcium alkaline series I-type granite. The Triassic and Early Jurassic sedimentary in the study area and Great Hinggan Mountains were deficient according to the discrimination diagram of tectonic setting, which means that the granodiorite of Luohe pluton belongs to the post-collision granite. Combined with the characteristics of the early-middle Jurassic intrusive rocks around the study area, the Luohe pluton is considered to be formed in the post collisional tectonic environment after the closure of Mongolia Okhotsk ocean. |
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| Keywords: | Middle Jurassic zircon U-Pb age geochemical characteristics I-type granite Luohe pluton |
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