湖南杏枫山金矿区首次发现高品位的钨矿体

The first discovery of tungsten orebodies with high ore grades in the Xingfengshan Gold Deposit, Longhui County, Hunan Province

湖南隆回县杏枫山金矿床位于雪峰山弧形构造隆起带的中段,白马山岩体南缘,是一产于新元古界浅变质岩中的石英细脉型金矿,目前已开采了30余年。最近,笔者在该金矿区新发现了矽卡岩和高品位的钨矿体,这类矽卡岩型钨矿床,明显不同于雪峰山一带广泛分布的石英脉型钨矿床。该区矽卡岩在矿区非常发育,主要呈层状、似层状产出,与地层呈整合接触;白钨矿主要是以条带状、脉状充填于矽卡岩之中,少量分布于含金的石英脉中;该区钨矿石的品位高,所有中段矿石WO_3平均含量均在0.5%以上,部分中段可达到3.0%以上。初步研究显示,该区矽卡岩为一还原性矽卡岩,结合其层状产出特征,可推断杏枫山为一品位高、资源潜力大的钨矿床。杏枫山金矿区矽卡岩和钨矿体的发现,不仅具有十分重要的经济价值和社会效益,而且对认识湘中地区岩浆岩的演化与钨、金成矿,也很有价值。

The Xingfengshan gold deposit,located in the central part of the Xuefengshan arc uplift belt,is a typical quartz lode gold deposit hosted in Neoproterozoic meta-metamorphic rocks. This deposit has been mined for gold for more than 30 years. Recently,skarn and tungsten orebodies with high ore grades in skarns were first discovered by writer in this gold deposit. The newly-discovered skarn-type tungsten deposit is obviously different from those lode-type tungsten deposits,which are widespread throughout the Xuefengshan arc uplift belt. Skarn is common throughout the Xingfengshan ore district,however,it was not identified during the past several decades.The skarn is concordant to the host slate and usually occurs in the bedded or stratiform form. Most scheelite occurs as bands or veinlets filling in the skarn,minor appears in the auriferous quartz veins. Generally speaking,the tungsten concentrations in skarn-type ores are relatively high in the Xingfengshan,with an average of more than 0.5% WO3 for most mining levels,even as high as more than 3. 0% WO3 for a few mining levels. Based on its strata-bound characteristics and its reduced signature,it can be concluded that the accumulations of tungsten ores in the Xingshanfeng ore district is abundant. The discovery of skarn-type tungsten orebodies with an extremely-high ore grade in the Xingfengshan ore district will bring abundant tungsten resources,and yield remarkable social and economic benefits,moreover,this new finding is crucial for the understanding of the felsic magma evolution and tungsten-gold mineralization in central Hunan.