南岭地区诸广山复式岩体年代格架研究  

Chronological Framework of the Zhuguangshan Composite Batholith in the Nanling Area

作　　者：夏金龙[1,2] 黄圭成 定立[1,2] 丁丽雪 陈希清[1,2] 季文兵 XIA Jin-Long;HUANG Gui-Cheng;DING Li;DING Li-Xue;CHEN Xi-Qing;JI Wen-Bing(Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey,Wuhan 430205,Hubei,China;Wuhan Center of China Geological Survey(Central South China Innovation Center for Geosciences),Wuhan 430205,Hubei,China;Nanjing Institute of Environmental Sciences,Ministry of Ecology and Environment,Nanjing 210042,Jiangsu,China)

机构地区：[1]中国地质调查局花岗岩成岩成矿地质研究中心,武汉430205 [2]中国地质调查局武汉地质调查中心(中南地质科技创新中心),武汉430205 [3]生态环境部南京环境科学研究所,南京210042

出　　处：《华南地质》2021年第3期280-297,共18页South China Geology

基　　金：中国地质调查局地质调查项目(12120114005901、DD20160034、DD20190154)资助。

摘　　要：诸广山岩体是南岭地区著名的大型复式岩体之一,但其研究程度存在南体高、北体低的不均衡现象,制约了对诸广山岩体年代格架及其岩石组成的整体性认识。本文对诸广山复式岩体(北体)进行锆石年代研究,测得早古生代汤湖岩体、寨前岩体、东洛岩体(黑云母二长花岗岩)锆石U-Pb年龄分别为444±2 Ma、448±3 Ma、440±2 Ma,桂东岩体和上堡岩体(黑云母花岗闪长岩)锆石U-Pb年龄分别为444±2 Ma、442±2 Ma;中生代淋洋岩体(二长花岗岩)和鹅形岩体(正长花岗岩)锆石U-Pb年龄分别为230±3 Ma、157±1 Ma。诸广山岩体(北体)是由晚奥陶世-早志留世、晚三叠世、晚侏罗世岩体组成的复式岩体。结合南体年代与岩石学资料,认为诸广山复式岩体的侵位可划分为晚奥陶世-早志留世、中-晚三叠世、晚侏罗世三个期次,相应的岩石组合大致由花岗闪长岩-二长花岗岩→二长花岗岩→二长花岗岩-正长花岗岩演变,与显生宙南岭地区地壳物质成熟度逐渐增高的总趋势一致,这可能为晚中生代该区发生钨锡铍铌钽铀等战略性矿产大规模、集群式成矿奠定了物质基础。汤湖岩体和寨前岩体中存在的新元古代继承锆石和捕获锆石暗示本区早古生代岩体形成过程中可能有新元古代物质的参与。The Zhuguangshan composite batholith is one of the well-known large-scale composite batholiths in the Nanling area.However,the research degree of the north pare is relatively poor,compared with the south part,which restricts the overall understanding of the chronology framework and rock composition of the Zhuguangshan batholith.Zircon U-Pb chronological studies of the Zhuguangshan batholith(the north part)show that the ages of Early Paleozoic Tanghu pluton,Zhaiqian pluton and Dongluo pluton(with lithofacies of biotite monzonite)are 444±2 Ma,448±3 Ma and 440±2 Ma,respectively,and the ages of Early Paleozoic Guidong pluton and the Shangbao pluton(with lithofacies of biotite granodiorite)are 444±2 Ma and 442±2 Ma,respectively.The ages of the Linyang pluton(with lithofacies of monzogranite)and the Exing pluton(with lithofacies of syenogranite)are 230±3 Ma and 157±1 Ma,respectively.The Zhuguangshan composite batho-lith(the north part)was emplaced in three periods,which are late Ordovician-Early Silurian,Late Triassic and Late Jurassic.In combination with the datum of previous research,it is considered that the formation of the Zhuguangshan composite batholith can be divided into three intrusive periods,such as Late Ordovician-Early Silurian,Middle-Late Triassic and Late Jurassic,and the corresponding rock assemblages roughly evolve from granodiorite,monzogranite→monzogranite→monzogranite,syenogranite,consistenting with the increasing trend of crustal maturity in the Nanling area during Phanerozoic.This may lay an important geological foun-dation for large-scale cluster mineralization of strategic minerals such as Tungsten,Tin,Beryllium,Niobium,Tantalum and Uranium in the Nanling area during Late Mesozoic.Neoproterozoic inherited and captured zir-cons are found in the Tanghu pluton and the Zhaiqian pluton,indicating that Neoproterozoic materials may be involved in the formation of early Paleozoic rocks in this area.

关 键 词：年代格架 锆石U-PB年龄 花岗岩 诸广山复式岩体 南岭 

分 类 号：P581[天文地球—岩石学]