小秦岭大湖矿区钼、金矿体地质、地球化学特征与差异性分析

Geological and Geochemical Features of Gold and Molybdenum Ore Bodies in Dahu Deposit,Xiaoqinling Area,and an Analysis on Their Differences

本文针对小秦岭金矿田大湖钼金矿矿床地质、地球化学特征进行了系统的分析。矿区浅部为石英脉型金矿体,向深部延伸出现石英脉型钼矿体,F5断层是大湖矿区内金、钼矿主要的含矿构造,钼矿体与金矿体共生或独立存在。钼矿体顶板围岩主要发育钾长石化,而金矿体顶底板围岩则发育硅化、绢云母化、黄铁矿化,其中绢云母化和中细粒黄铁矿化与金矿体关系最为密切。含金石英脉流体包裹体气相组分以CO2、H2O为主,含有少量CH4、C2H2等还原性气体,液相组分主要为Na+、Ca2+、Cl-、F-等离子。钼矿体与金矿体的H、O同位素数据显示钼矿脉与金矿脉的成矿流体主要都是来自岩浆水,但是两种矿体的H、O同位素组成又表现出一定的差异。辉钼矿化石英脉与金矿体中钾长石化和黄铁矿化石英脉中的稀土组成具有明显的不同,辉钼矿化石英脉具有较高的的∑REE和轻重稀土分馏,指示金矿体与钼矿体成矿流体来源不同,金、钼可能形成于不同的成矿期。

This paper makes a systematical geochemical analysis on the Dahu molybdenum gold deposit in Xiaoqinling Area. The main gas compositions of the fluid inclusion are CO2 ,H2O and a little of reducing gas, such as C H4 and C2 H2. The main liquid components are Na ＋, Ca2＋ , Cl- ,F-, etc. Hydrogen and Oxygen isotope display ore-forming fluid of molybdenum and gold deposit were mainly from magma water, but the Hydrogen and Oxygen isotope of the kinds of ore bodies also show some differences. Rare earth compositions of the molybdenumization quartz vein and potash feldspathization,pyritization quartz vein have obvious differences, molybdenumization quartz vein has higher ∑REE and LREE-HREE fractionation, the ore-forming fluid source of gold and molybdenum may be different, molybdenum and gold ore bodies maybe formed in different period.