河南栾川中鱼库矽卡岩矿物学特征及地质意义

河南栾川中鱼库硫锌多金属矿床是近年来发现的矽卡岩型硫锌多金属矿床,为进一步探讨其成矿机制,本文以矽卡岩矿物为研究对象,开展了野外观察、岩矿鉴定和电子探针分析综合研究。研究表明,矿床成矿阶段可细分为早矽卡岩阶段、退化蚀变阶段(晚矽卡岩阶段)、石英-硫化物阶段、石英-碳酸盐阶段。该矿床矽卡岩为交代成因的钙矽卡岩,石榴子石以钙铁榴石-钙铝榴石系列为主,辉石以透辉石-钙铁辉石系列为主,帘石主要为绿帘石,角闪石为钙角闪石,绿泥石为铁镁绿泥石。石榴子石、辉石端元组分特征显示矽卡岩阶段成矿流体经历了从酸性到碱性、从还原到氧化的转变。随着流体演变,从退化蚀变阶段到石英-硫化物阶段,成岩成矿环境逐渐从氧化环境过渡到还原环境。石英-硫化物阶段是成矿主阶段,在此阶段金属硫化物大量富集和沉淀。

Characteristics and geological significance of skarn minerals from the Zhongyuku sulfide-zinc polymetallic deposit in Luanchuan,Henan, China

Systematic field work,microscopic identification and electron microprobe technology are carried out to study the mineralogical characteristics of skarn and to discuss the petrogenic and metallogenic mechanism in the Zhongyuku sulfide-zinc polymetallic deposit.It reveals that the ore deposit has experienced four ore-forming stages,such as skarn stage,retrograde alteration stage,quartz sulfide stage and carbonate stage,respectively.The skarns in the Zhongyuku deposit belong to typical calcic skarns resulted from the replacement of granitoid magma.Garnets in the ore deposit are mainly composed of andradite-grossularite and the pyroxenes mainly belonging to diopside-andradite series.Amphiboles in the ore show characteristics of calciferous amphibole,and the chlorites are mainly brunsvigite.Components of garnet and pyroxene suggest that the ore-forming fluid have an evolutionary trend from acidic to basic and from reduction to oxidation condition at the skarn stage.From the retrograde alteration stage to the quartz sulfide stage,the oxygen fugacity drops with the evolutionary of ore-forming fluid.The metal sulfides are precipitated at the quartz sulfide stage.