冀西栾木厂金矿地球化学特征及成因初探

Geochemical features and genesis of Luanmuchang gold deposit in Western Hebei province

栾木厂金矿位于华北地台北缘中段金多金属成矿区内,矿区发现金矿脉4条,其中以2号金矿脉为主。现已探获(332)资源量接近4t。文章通过氢、氧同位素分析得出:该区成矿流体水具有多来源特征。矿床中黄铁矿δ34S的组成特点反映了硫源可能来自地壳深部或上地幔。矿石稀土元素表现为富轻稀土,贫重稀土。金矿成矿于燕山晚期,成矿热液中金主要以硫化物配合物的形式迁移,并与围岩发生充分的物质交换后运移到裂隙发育部位,并因为流体的混合和围压突然降低,成矿流体产生强烈的沸腾作用,使成矿物质沉淀富集成矿。

Luanmuchang gold deposit is located in the gold polymetallic mineralization zone of the middle part of the northern edge of north China platform. Four gold veins have been discovered in the mining area, and No. 2 is the main one. Now nearly four tons of gold resources（332） have been explored. Through the analysis of hydrogen and oxygen isotope, the article suggests that the source of metallogenic fluid in the area is multiple. The composition feature of pyrite δ^34S in the deposit possibly reflects that sulfur is from deep crust or upper mantle. Rare earth elements of ores are mainly rich in light REE, andpoor in heavy REE. Gold mineralization occurred in late Yanshan epoch. In the metallogenic hydrotherm, gold was transferred mainly in sulfide and moved to the places where fissures developed after interacting with wall rock for material exchanges. Then because of the mixture of fluid and decrease of pressure around, metallogenic fluid boils intensely, which makemetallogenic material presentates and enriches into deposit.