花岗岩与金铜及钨锡成矿的关系

2010年10月October,2010 矿 床 地 质

M I NERAL DEPO SI T S

第29卷 第5期

Vol.29 No.5

文章编号:0258-7106(2010)05-0729-31

花岗岩与金铜及钨锡成矿的关系

张 旗1,金惟俊1,王 焰2,李承东3,王元龙1

(1中国科学院地质与地球物理研究所,北京 100029;2中国科学院广州地球化学研究所,广东广州 510640;

3中国地质调查局天津地质矿产研究所,天津 300170)

摘 要 文章从对国内外若干与金铜钨锡矿床有关的花岗岩Sr、Yb含量的统计出发,按照花岗岩新的分类,归纳了花岗岩与成矿的关系。指出金铜成矿与埃达克型和喜马拉雅型花岗岩有关,钨锡成矿与南岭型花岗岩有关。

其原因主要取决于成岩和成矿的深度以及氧逸度条件。金铜和钨锡成矿的深度不同,因此,金铜和钨锡不可能在同时同地出现,但可以叠加在一起。作者认为,成岩和成矿是两回事,成岩基本上是一个物理过程,而成矿主要体现为化学反应;成岩需要热,而成矿需要热、流体以及合适的矿源3个条件,缺一不可。在一个地区,成岩作用可以很普遍,但是,成矿可能很局限。成岩与成矿有关不是成因有关而是时空有关。成矿与成岩同时、或成矿早于成岩、或晚于成岩,都是合理的,而区分含矿岩体和不含矿岩体可能是没有意义的。文中还讨论了金能否来源于围岩的问题及找矿思路的问题,指出就矿找矿仍然是行之有效的找矿方法。

关键词 地质学;花岗岩;金矿;斑岩铜矿;钨锡矿;成岩作用;成矿作用

中图分类号:P618.51;P618.41;P618.67;P618.44 文献标志码:A

Relationship between granitic rocks and Au-Cu-W-Sn mineralization ZHANG Qi1,JIN WeiJun1,WANG Yan2,LI Cheng Dong3and WANG YuanLong1

(1Institute of Geolog y and G eophysics,Chinese Academy o f Sciences,Beijing100029,China;

2Guangzhou Institute of Geochemistry,Chinese A cademy of Sciences,Guangzhou510640,G uang dong;China;

3T ianjin I nstitute of G eolo gy and M ineral R esources,China Geological Survey,T ianjin300170,China)

Abstract

Sr and Yb concentrations of grantitic rocks related to Au-Cu-W-Sn mineralization in the w orld are summarized in this paper.According to the classification of Sr versus Yb for granitic rocks,the authors hold that Au-Cu mineralization m ay be associated with adakitic type and Himalay an type granitic rocks,w hereas W-Sn mine-ralization may be related to Nanling-type granitic rocks.The crucial factors for different metallic ore de posits hosted in g ranitic rocks are formation depth and f(O2),Consequently,Au-Cu mineralization cannot be coex istent w ith W-Sn mineralization at the same time and in the sam e locality unless the two kinds of mineral ization w ere superimposed on each other afterw ards.It is considered that granitic rocks and related ore deposits mig ht have been formed by tw o independent processes:the formation of granitic rocks was controlled by heat of source rocks,whereas the formation of ore deposits was controlled by three compulsory factors,i.e.,heat,fluid and suitable metal sources.T herefore,ore mineralization is alw ays restricted in certain localities.Au-Cu-W-Sn ore deposits may not have a direct genetic connection w ith the host granitic rocks.It is probable that ore de posits might have been formed earlier or later than or simultaneously w ith spatially associated granitic rocks.

Key words:geology,granitic rocks,gold deposit,porphyry Cu deposit,W-Sn deposit,lithogenesis,ore -forming process

本文得到中国科学院地质与地球物理研究所岩石圈演化国家重点实验室和国家自然科学基金重大研究计划(90714011和90714007)资助第一作者简介 张 旗,男,1937年生,研究员,岩石学和地球化学专业。Email:zq1937@

收稿日期 2010-03-10;改回日期 2010-07-30。张绮玲编辑。