地球学报2012，Vol.33Issue(4)：444-458,15.DOI:10.3975/cagsb.2012.04.06
西藏甲玛铜多金属矿床角岩中黑云母矿物化学特征及地质意义
Mineral Chemical Characteristics of Biotites from Hornfels in the Jiama(Gyama) Polymetallic Copper Deposit of Tibet and Their Geological Significance
摘要
Abstract
Biotite from hornfels in the Jiama(Gyama) polymetallic copper deposit can be classified into primary biotite and hydrothermal one. Two sorts of biotite were observed by SEM and measured by EMPA. The authors calculated the chemical formula of biotite on the basis of EMPA data. Both primary and hydrothermal biotites are magnesian biotites and have experienced hydrothermal alterations. Magma-hydrothermal fluids were gradually converted into oxidation state, as evidenced by the increase of Fe3+ and decrease of Fe2+, the increasing differentiation between Fe3+ and Fe2+, and the decrease of K, Na and Ca content from primary biotite to hydrothermal one. Compared with things of primary biotite, more Cu was likely to be concentrated in hydrothermal biotite. The Cu content of rocks has positive correlation with Fe2+/(Fe2++Mg2+) of biotite, and negative correlation with Fe3+/Fe2+ in hydrothermal biotites, which suggests that the mineralization intensity of hornfels-type ores containing hydrothermal biotites might be judged by Fe2+/(Fe2++Mg2+) ratio of hydrothermal biotites; nevertheless, Mo is spread in two sorts of biotite diffusely, and doesn't have characteristics of selective occurrence.关键词
角岩/原生黑云母/热液黑云母/镁质黑云母/化学特征/Cu、Mo/成矿指示/SEM/EMPAKey words
hornfels/ primary biotite/ hydrothermal biotite/ magnesian biotite/ chemical characteristics/ Cu and Mo/ ore-forming indicator/ SEM/ EMPA分类
天文与地球科学引用本文复制引用
王崴平,唐菊兴,应立娟..西藏甲玛铜多金属矿床角岩中黑云母矿物化学特征及地质意义[J].地球学报,2012,33(4):444-458,15.基金项目
本文由国家973项目(编号:2011CB403103)、危机矿山接替资源找矿专项典型矿床及成矿规律总结研究项目(编号:20089932)和青藏专项(编号:1212010012005)联合资助. （编号:2011CB403103）
