摘要
大宝山是粤北独具特色的铜多金属矿区,其矿床成因一直争议不休。本文在野外工作的基础上,通过对大宝山矿区次英安斑岩的岩石学、地球化学、同位素年代学、锆石微量和矿质迁移定量分析,认为大宝山矿区次英安斑岩是早侏罗世晚期(～175 Ma)沿逆冲推覆构造侵位的次火山岩,并捕获了大量志留纪岩浆锆石。铜多金属矿化具有斑岩型矿床特征,次英安斑岩与灰岩接触时外接触带形成的矽卡岩中赋存块状、层状、似层状矿体;与泥质、长英质岩石接触时,由于外接触带角岩的流体圈闭作用,在岩体内形成了细脉状铜多金属矿化和绢英岩化。大宝山和九曲岭次英安斑岩既是成矿母岩又是有利的赋矿围岩,铜多金属矿的成矿流体是次英安斑岩深部岩浆房晚期去气作用排出的含矿热液,其中富含SiO_2、Fe_2O_3、K_2O、Mo、W、Cu、Rb、Th、U、Bi、Tl、Cs、In、Cd、Be和挥发分等,具有强氧化(Fe^(3+)/Fe^(2+)平均值为8.55)、高交代参数(K^+/Na^+平均值为56.62)的特征,并于围岩交代过程中,萃取其中的TiO_2、FeO、MnO、CaO、Na_2O、P_2O_5、REE及Sc、Pb、Ba、Sr、Ni、Mn、Zr等。
The Dabaoshan is a unique Cu-polymetallic deposit and its genesis is still a matter of debate.On the basis of orefield geological survey,we studied the petrology,petrography,geochemistry,isotope chronology and zircon trace element characteristics of the porphyritic dacite,and estimated migration of the components during alteration.The results indicate that the porphyritic dacite in the Dabaoshan orefield intruded into a thrust nappe structure at the end of early Jurassic Period(about 175 Ma),and it captured lots of zircon grains from the Silurian magmatic rocks.The ores show features of typical porphyry deposit.The ore bodies are massive,stratiform,and strata-like in skarn,and veins in the porphyritic dacite.It is evident to infer that the Dabaoshan and Jiuquling porphyritic dacites are genetically related to the Cu-polymetallic mineralization.We further argue that the Cu-polymetallic deposit is of porphyry type,and the ore-bearing fluids are characterized by rich SiO 2,Fe 2 O 3,K 2 O,Mo,W,Cu,Rb,Th,U,Bi,Tl,Cs,In,Cd,Be and volatiles,and strongly oxidizing(Fe^3+/Fe^2+=8.55),moreover,the ore-bearing fluids may extract TiO 2,FeO,MnO,CaO,Na 2 O,P 2 O 5,REEs,Sc,Pb,Ba,Sr,Ni,Mn and Zr from the porphyritic dacite during the profound potash metasomatism.
作者
赵如意
陈毓川
王登红
蒋金昌
应立娟
张熊
刘战庆
王要武
ZHAO Ruyi;CHEN Yuchuan;WANG Denghong;JIANG Jinchang;YING Lijuan;ZHANG Xiong;LIU Zhanqing;WANG Yaowu(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resource,CAGS,Beijing 100037,China;Guangdong Province Dabaoshan Mining co.,Ltd.,Shaoguan 512127,Guangdong,China;College of Earth Sciences,Guilin University of Technology,Guilin 541004,Guangxi,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2019年第1期123-140,共18页
Geotectonica et Metallogenia
基金
中国地质调查局中国矿产地质与成矿规律综合集成和服务(矿产地质志)项目(DD20160346)
大宝山矿床外围(深部)找矿方向研究项目(HE1806)联合资助
关键词
大宝山
多金属矿
次英安斑岩
矿质迁移
成矿作用
Dabaoshan
Cu-polymetallic
the porphyritic dacite
mineral components migration
metallogenesis
