甘肃北山南金山金矿床地质特征及深部成矿预测

Geological Features of Nanjinshan Gold Deposit and Prediction to Mineralization at Depth in the Beishan Area,Gansu Province

南金山金矿是北山地区典型的浅成低温热液型金矿床,原20万化探扫面中在该矿床处存在W、Mo等高温元素异常组合,明显异于一般浅成低温热液矿床仅存在中低温元素异常组合。作者在系列成矿找矿思路的指导下,采集了南金山金矿床不同深度的地球化学样品,剖析该矿矿床特征、蚀变矿化特征、成矿元素的富集规律,指出该矿床是一典型的高硫型浅成低温热液矿床,矿床高温元素W、Mo,中温元素Cu向深部增高。并通过与典型铜金矿床地化特征、国外高硫型浅成低温热液型矿床与相关铜金矿床空间配位的类比,提出了南金山金矿深部存在斑岩型铜矿的可能。

The Nanjinshan gold deposit is a typical epithermal deposit in the Beishan area,Gansu Province. As shown on the map of original geochemical reconnaissace of scale 1：200000,there as an abnormal combination of W,Mo and other high-temperature elements in this deposit,significantly different from general epithermal deposits where exists only an abnormal combination of low temperature elements. Under the guidance of the prospecting thought based on series mineralization theory,we have collected geochemical samples of the Nanjinshan gold deposit at different depths,analyzed the characteristics of the ore deposit,alteration and mineralization,and the enrichment of ore-forming elements. We noted that this deposit is a typical high-sulphidation epithermal deposit with high-temperature elements of W,Mo and medium temperature element Cu that increases with depth. By comparing it with the typical geochemical characteristics of copper-gold deposits,high-sulphidation epithermal deposits in other countries and spatial configuration of related copper-gold deposits,this work suggests that the a porphyry copper deposit probably exists at depth in the Nanjinshan gold deposit area.