岩矿测试2016，Vol.35Issue(4)：440-447,8.DOI:10.15898/j.cnki.11-2131/td.2016.04.017
西藏邦铺斑岩钼（铜）矿床钾硅酸盐化热液黑云母电子探针分析及早期成矿流体特征
EPMA Analysis of Hydrothermal Biotite from the Bangpu Porphyry Mo-Cu Deposit of Tibet, China and the Characteristics of Early Ore-forming Fluids
摘要
Abstract
The chemical composition of hydrothermal biotite is important in revealing the physiochemical conditions and evolution of early ore-forming fluids.The Bangpu deposit is a large porphyry Mo (Cu )deposit in the eastern part of the Gangdese metallogenic belt,and hydrothermal biotite is extensive in the potassic alteration zone.Hydrothermal biotite in the potassic alteration zone of dioritic porphyry was analyzed by Electron Microprobe Analyzer (EPMA)and is reported in this paper.Results show that the biotite is characterized by the high content of K and low contents of Na and Ca. The average contents of SiO2,TiO2,Al2 O3,FeOT,MgO,K2 O are 38.95%,1.42%,13.55%,14.22%,16.23%, 9.77%,respectively.The anomalously high K/Na values (82.5)may be an important indicator for the porphyry Mo mineralization.Based on chemical components,the temperature and oxygen fugacity of the ore-forming fluids were calculated.Results show that the early ore-forming fluids of the potassic alteration have a high temperature and oxygen fugacity,and the average temperature (458℃)of the deep ore-forming fluids is much higher than that of the shallow ore-forming fluids (366℃).The decreasing temperature and pressure during the migration of the early ore-forming fluids from deep to shallow resulted in the precipitation of the Mo and Cu sulfides.This research provides an important clue for studying the evolution of ore-forming fluids and the ore-forming mechanism.关键词
热液黑云母/电子探针/物理化学条件/斑岩型矿床/邦铺Key words
hydrothermal biotite/Electron Microprobe/physico-chemical condition/porphyry deposit/Bangpu分类
天文与地球科学引用本文复制引用
王勇,唐菊兴,王立强..西藏邦铺斑岩钼（铜）矿床钾硅酸盐化热液黑云母电子探针分析及早期成矿流体特征[J].岩矿测试,2016,35(4):440-447,8.基金项目
国家自然科学基金资助项目(41403040),中国地质调查局地质调查项目(12120115028301),中央级公益性科研院所基本科研业务费专项(K1416) （41403040）
