金青顶金矿床成矿流体的空间定位机制

The Localizing Mechanism of Ore-Forming Fluids in the Jinqingding Gold Deposit

综合评述了金青顶金矿矿化分带、成矿年龄、流体包裹体以及深部采矿露头新资料。经过详细的观察,确认了一批流体成矿构造证据。结合不同赋存标高上的成矿元素、矿物组合、流体包裹体的温度、压力和成分的分布特征,提出了该矿床新的成矿流体定位机理:该矿床是由一期中高温高压成矿流体经降温降压侵入定位、形成成矿流体的固结外壳后,再经未固结的残余流体发生第二次内爆沸腾、快速降温降压固结的产物。金成矿作用发生在两期流体与围岩作用阶段:(1)深部以金为主的降温降压结晶固结,(2)浅部金—多金属隐爆结晶固结,从而导致金青顶金矿的矿化分带现象。对于矿体分带规律的新认识,有助于指导该区区域成矿规律研究和深部找矿工作。

The new data of metallogenic epochs, the zoning of the mineralization , fluid inclusions and deep mining outcrops in the Jinqingding gold deposit have been reviewed comprehensively. Through the detailed observation, a group of fluid metallogenic structural evidence has been confirmed. In combination with the distribution characteristics of metallogenic elements, mineral associations, fluid inclusions with their their trapping temperatures, pressures and compositions at different elevations, the paper proposes the new localizing mechanism of ore-forming fluids in the deposit. The ore-forming fluids with medium-high temperatures mainly originated from the magma. The deposit was the product of secondary cryptoexplosion, boiling, rapid dropping of pressure and temperature of unsolidified relict fluids which derived from the primary ore-forming fluids of medium-high temperature and high pressure at one epoch which invaded, localized at the depth and formed the solidified crust after the first dropping of temperature and pressure. It seems that gold mineralization happened in two stages of fluid-host rock interaction: (1) dominant gold crystallization and solidification in the depth after the dropping of temperatures and pressures; (2) gold and multiple metal crystallization and solidification at shallow parts after the crytoexplosion. Consequently, the Jinqingding deposit possess the zoning features of metallogeny. The new knowledge of ore body zoning metallogeny helps to direct regional mineralization regularity studies and deep prospecting work in the district.