华南诸广山一带桂东岩体年代学、岩石地球化学特征及地质意义  

Geochronology,petrogeochemistry and geological significance of Guidong batholith in Zhuguangshan area,South China

作　　者：张素梅 苏天瑞 朱俊宾[3] 任纪舜[3] 汪洋[2] 张敏杰 于延秋 王霄汉 朱丽娜 井天景 Zhang Sumei;Su Tianrui;Zhu Junbin;Ren Jishun;Wang Yang;Zhang Minjie;Yu Yanqiu;Wang Xiaohan;Zhu Lina;Jing Tianjing(Hebei Key Laboratory of Strategic Mineral Resources,College of Earth Sciences,Hebei GEO University,Shijiazhuang 050031;College of Earth Science and Resources,China University of Geosciences,Beijing 100083;Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037;Huaxin College of Hebei GEO University,Shijiazhuang 050031)

机构地区：[1]河北省战略性关键矿产资源重点实验室,河北地质大学地球科学学院,石家庄050031 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院地质研究所,北京100037 [4]河北地质大学华信学院,石家庄050031

出　　处：《地质科学》2024年第6期1722-1747,共26页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：河北省青年科学基金项目(编号:D2022403023);河北省斑岩型矿床研究重点实验室项目(编号:HBBY202401);河北省青年科学基金项目(编号:D2022403023);河北地质大学教学改革研究项目(编号:2014J17,2016J19)资助。

摘　　要：华南加里东期岩浆岩是否具有陆内成因,幔源岩浆参与情况是华南早古生代构造—岩浆演化研究中长期争论的重要科学问题。本文通过远离大陆边缘的桂东岩体的年代学、岩石地球化学等特征来探讨诸广山一带的加里东期岩浆活动特征、幔源物质参与程度及大地构造背景,将为进一步揭示华南早古代岩浆岩的构造—岩浆演化过程提供重要信息。锆石U-Pb年代学、岩石地球化学及锆石Lu-Hf同位素结果表明,岩石总体具有高硅(SiO_(2)=63.31%~75.53%)、高铝(Al_(2)O_(3)=11.95%~17.29%)、高碱(Na_(2)O+K_(2)O=4.09%~9.31%)、低铁(Fe_(2)O_(3)=0.02%~2.91%、FeO=0.17%~5.37%)特征;早奥陶世末—早志留世末(474~434 Ma)期间,研究区处于挤压为主的大地构造背景之下,并伴生了早奥陶世末至中奥陶世(474~464 Ma)的壳源型、晚奥陶世—早泥盆世(452~442 Ma)及早志留世(438~434 Ma)混合源型花岗质岩浆岩,岩石中角闪石的含量较高,壳幔相互作用较强;早志留世末至中志留世初(438~434 Ma)期间,研究区的构造属性可能开始发生转换,壳幔相互作用达到最强,但岩石中基本不含角闪石;中志留世—早泥盆世末(430~410 Ma)期间,研究区整体处于伸展拉张为主的构造背景中,并伴生了中志留世(430~425 Ma)壳源为主的混合源型及晚志留世末—早泥盆世(415~410 Ma)的壳源型花岗质岩浆岩,岩石中的角闪石含量相对较低,中志留世研究区的岩浆混合作用较强,之后减弱,研究区的岩浆活动逐渐结束。The origin of the Caledonian magmatic rocks in South China and the degree to which they involve magmas derived from the mantle have been enduring scientific questions concerning the Early Paleozoic tectono-magmatic evolution of the region.This paper explores the characteristics of Caledonian magmatic activity,the degree of participation of mantle-derived materials,and the tectonic setting in the Zhuguangshan area through the chronological and petrogeochemical characteristics of the Guidong batholith,which is far from the continental margin.This provides important information for further revealing the tectono-magmatic evolution process of the Early Paleozoic magmatic rocks in South China.Zircon U-Pb geochronology,petrogeochemistry and zircon Lu-Hf isotope results indicate that the rocks generally have high silicon(SiO_(2)=63.31%~75.53%),high aluminum(Al_(2)O_(3)=11.95%~17.29%),high alkali(Na_(2)O+K_(2)O=4.09%~9.31%),and low iron(Fe_(2)O_(3)=0.02%~2.91%,FeO=0.17%~5.37%)characteristics;during the late Early Ordovician to the late Early Silurian(474~434 Ma),the study area was under a tectonic setting dominated by compression,accompanied by crust-derived,mixed-source granitic magmatism from the late Early Ordovician to the Middle Ordovician(474~464 Ma),and from the Late Ordovician to the Early Devonian(452~442 Ma)and Early Silurian(438~434 Ma).The rocks have a relatively high content of amphibole,indicating strong crust-mantle interaction.During the late Early Silurian to the early Middle Silurian(438~434 Ma),the tectonic of the study area may have begun to transform,with the strongest crust-mantle interaction,but the rocks contain few amphiboles.Later,South China orogenic belt was dominated by extensional rifting during the Middle Silurian to the late Early Devonian(430~410 Ma),accompanied by crust-derived,mixed-source granitic magmatism from the Middle Silurian(430~425 Ma)and crust-derived granitic magmatism from the Late Silurian to the Early Devonian(415~410 Ma).These rocks have a relatively lower amphibole conten

关 键 词：华南 桂东岩体 U-PB年代学 加里东期 岩石地球化学 

分 类 号：P588.1[天文地球—岩石学] P59[天文地球—地质学]