对与氧逸度有关的花岗岩类成矿专属性-含矿性问题的再思考  

Rethinking of the metallogenic specialization and ore-bearing potential of redox-related granitoid

作　　者：赵博[1] 张德会[1] 石成龙[1] 张荣臻[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石矿物学杂志》2014年第5期955-964,共10页Acta Petrologica et Mineralogica

基　　金：中国地质调查局工作项目(资[2013]01_036_010)

摘　　要：花岗岩类的成矿专属性与氧逸度密切相关,但氧逸度只是矿床形成时的必要非充分条件之一。本文从成矿专属性和含矿性两个方面讨论氧逸度的成矿学意义,得到两点主要认识:还原性斑岩型Cu_Au多金属矿床具有高氧逸度成因,不同元素的矿化分别对应于氧逸度对演化程度、岩石类型、硫逸度、pH协变图上的不同分区,其中可能以氧逸度和岩石类型这两种因素的配合最具专属性意义;从专属性到成矿性分从岩浆到热液、从热液到矿石两个阶段完成,这期间氧逸度对元素地球化学行为的影响不容忽视,但其在矿质沉淀过程中的角色有时不宜夸大,因为有的沉淀与氧逸度关系不大。The ore-forming metallogenic specialization of felsic rocks is closely related to oxygen fugacity.In this paper,however,oxygen fugacity is considered to be one of the necessary but not sufficient conditions for ore formation,and the analytical thinking concerned is partly based on the authors＇ geological field work.The metallogenic significance of oxygen fugacity is divided into metallogenic specialization and ore-bearing potential.Two aspects of understanding have been otained：① Porphyry Cu-Au deposits derived from the reduced I-type granitoid should have a high oxygen-fugacity origin; different sub-regions within the covariogram of oxygen fugacity versus other geochemical parameters,such as degree of magrnatic evolution,temperature,pressure,pH,sulfur fugacity and rock-type,correspond to different metals＇ geochemical behavior or mineralization,respectively,and oxygen fugacity versus rock-type seems to be of significant specialization; ② The evolution from metallogenic specialization to real metallogenesis is the evolution from magma to hydrothermal solution and then from hydrothermal solution to ore; during such a process,oxygen fugacity is also an essential controlling factor for elemental geochemical behaviors,whose influence on mineral precipitation,however,should not be overemphasized,because some kinds of precipitation might have had nothing to do with oxygen fugacity.

关 键 词：氧逸度(fO2) 地球化学参量 花岗岩类 成矿专属性 含矿性 

分 类 号：P588.121[天文地球—岩石学] P611[天文地球—地质学]