江西花山洞含钨隐爆角砾岩筒地质特征及成矿模式

花山洞钨矿床位于下扬子成矿亚区江南中部钨锡铜金金属成矿带九岭中段。通过对区内隐爆角砾岩岩相学研究,将其划分为中心带、过渡带、边缘带和外接触带。通过对钨矿赋存状态的分析研究,发现钨矿体严格受隐爆角砾岩筒构造控制,一般多赋存于中心带及过渡带中。岩筒外接触变质带较窄,热接触变质程度低,仅具弱角岩化;岩筒内矿化蚀变主要为碳酸盐化、绢云母化、硅化、云英岩化、钾长石化,其中钾长石化、碳酸盐化及云英岩化与成矿关系密切。研究表明,作为该区初始矿源层的双桥山群各岩性中W元素含量较高,岩浆的重熔作用使成矿物质进一步富集,并经隐爆作用运移沉淀,最终形成了该区隐爆角砾岩型钨矿体。

Geological characteristic and metallogenic model of tungsten-bearing concealed breccia pipe in Huashandong deposit area,Jiangxi

The Huashandong tungsten deposit is located in the central part of Jiangnan tungsten tin and copper-gold metallogenic belt within the downstream Yangtze metallogenic sub-zone. By detailed petrographic study of the concealed breccia which are closely related to mineralization, the breccia can be divided into four zones, i.e., central zone, transitional zone, marginal zone and outer contact zone. By the study of tungsten orebody occurence, it was found that the tungsten ore bodies are strictly controlled by concealed breccia pipe structure, and the tungsten orebodies are generally distributed in the central zone and the transition zone. The outer contact zone of pipe is narrow with low thermal contact metamorphism, there is only weak hornfelsed alteration. Main mineralized alterations within the pipe are carbonation, sericitization, silicification, greisenization and k-feldsparization, among them, the k-feldsparization, sericitization and silicification are closely related to the tungsten mineralization. The study result indicates that Shuangqiaoshan group is the initial ore-forming source bed with high W content, which was enriched by remelting of the magma, and the tungsten ore deposit was formed within the concealed breccia pipe structure finally.