| 冀北独石口古元古代变辉长闪长岩的成因及其地质意义 |
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| 引用本文： | 王芳,彭澎,陈超,胡洪飞,黄冬琴,陈福坤,翟明国.冀北独石口古元古代变辉长闪长岩的成因及其地质意义[J].岩石学报,2021,37(1):269-283. |
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| 作者姓名： | 王芳 彭澎 陈超 胡洪飞 黄冬琴 陈福坤 翟明国 |
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| 作者单位： | 河北省战略性关键矿产资源重点实验室, 石家庄 050031;河北地质大学地球科学学院, 石家庄 050031;中国科学院地质与地球物理研究所, 岩石圈演化国家重点实验室, 北京 100029;安徽省地质矿产勘查局313地质队, 六安 237010;浙江大学海洋学院, 舟山 316021;中国科学技术大学地球与空间科学学院, 合肥 230026 |
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| 基金项目： | 本文受国家自然科学基金重大项目（41800833）、河北省自然基金项目（D2019403015）、河北省高等学校科学技术研究项目（QN2018097、ZD2019003）和河北地质大学博士启动基金项目（BQ2017051）联合资助. |
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| 摘 要： | 为了对华北克拉通古元古代岩浆-变质-构造过程有更清晰的认识,本文对冀北赤城北独石口地区红旗营子杂岩中新发现的古元古代变辉长闪长岩进行了全岩主、微量元素,LA-ICP-MS锆石U-Pb年龄、微量元素和Hf同位素测试。独石口变辉长闪长岩具有典型拉斑系列岩浆岩的特征,SiO2含量变化范围为51.27%~54.39%,Na2O+K2O含量变化范围为4.65%~6.00%,Al2O3含量变化范围为14.74%~15.51%,MgO含量变化范围为2.19%~4.65%,Mg^#为28~47。岩石富集轻稀土元素和大离子亲石元素,亏损Nb、Ta等高场强元素,具有受到交代的岩石圈地幔部分熔融形成的岩浆作用的特征,代表壳-幔相互作用产物。独石口变辉长闪长岩中锆石呈自形-半自形晶,具有较高的Th/U比值,为岩浆成因,对2个变辉长闪长岩样品LA-ICP-MS锆石U-Pb定年结果分别为1808±18Ma和1825±18Ma,表明该岩体形成时代稍晚于古元古代区域变质作用峰期。锆石εHf(t)值变化范围为-5.4~+0.1,单阶段Hf模式年龄tDM1介于2236~2418Ma之间,说明除了太古宙岩石圈物质贡献,也存在新生地幔或者地壳物质的贡献。综合研究表明,独石口变辉长闪长岩可能代表古元古代造山带去根作用造成的区域抬升(伸展)的岩浆作用产物。
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| 关 键 词： | 变辉长闪长岩 红旗营子杂岩 锆石U-PB年龄 HF同位素 独石口 华北克拉通 |
| 收稿时间： | 2020/8/1 0:00:00 |
| 修稿时间： | 2020/11/4 0:00:00 |
Petrogenesis and geological significance of the Paleoproterozoic Dushikou metagabbro-diorite in northern Hebei Province |
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| WANG Fang,PENG Peng,CHEN Chao,HU HongFei,HUANG DongQin,CHEN FuKun,ZHAI MingGuo.Petrogenesis and geological significance of the Paleoproterozoic Dushikou metagabbro-diorite in northern Hebei Province[J].Acta Petrologica Sinica,2021,37(1):269-283. |
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| Authors: | WANG Fang PENG Peng CHEN Chao HU HongFei HUANG DongQin CHEN FuKun ZHAI MingGuo |
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| Institution: | Hebei Key Laboratory of Strategic Critical Mineral Resources, Shijiazhuang 050031, China;College of Earth Sciences, HeBei GEO University, Shijiazhuang 050031, China;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;313 Geological Team, Bureau of Geology and Mineral Resources Exploration of Anhui Province, Lu''an 237010, China;Ocean College, Zhejiang University, Zhoushan 316021, China;School of Earth and Space Sciences, Universities of Science and Technology of China, Hefei 230026, China |
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| Abstract: | A combined analysis of whole rock major and trace elements,LA-ICP-MS zircon U-Pb ages,trace element and Hf isotope of the Paleoproterozoic Dushikou metagabbro-diorite,which is newly discovered in the Hongqiyingzi complex,to the north of Chicheng,Hebei Province,are performed to better understand the Paleoproterozoic magmatism-metamorphism-tectonics of the North China Craton.This pluton has the features of typical tholeiitic magmatic rocks,with SiO2 contents of 51.27%~54.39%,Na2O+K2O of 4.65%~6.00%,Al2O3 of 14.74%~15.51%,MgO of 2.19%~4.65%and Mg^#ranging from 28 to 47.The rocks are rich in light rare earth elements and large ion lithophile elements,and depleted in high field strength elements such as Nb,Ta,etc.They are characterized by magmatism formed by partial melting of metasomatic lithospheric mantle,representing the products of crust-mantle interaction.Zircons in the metagabbro-diorite show high Th/U ratios,suggesting a magmatic origin.LA-ICP-MS zircon U-Pb dating results of two metagabbro-diorite samples are 1808±18Ma and 1825±18Ma,respectively,indicating that the pluton emplacement postponed the peak stage of regional metamorphism at Paleoproterozoic.TheεHf(t)values of dated zircons range from-5.4 to+0.1,with tDM1 from 2236Ma to 2418Ma,indicating that a mixture of juvenile mantle,Archean lithosphere mantle and some crustal materials in its magma generation.Consequently,the Dushikou metagabbro-diorite may represent the magmatic product of regional uplift(extension)probably induced by the loss of the root of the Paleoproterozoic orogeny. |
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| Keywords: | Metagabbro-diorite Hongqiyingzi Complex Zircon U-Pb ages Hf isotope Dushikou North China Craton |
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