摘要
The Yinshan silver polymetallic deposit of northwestern Zhejiang occurs in the Sinian Lantian Formation. Its orebodies display layered and bedded texture, and exhibit a significant tectonic control by folds and faults. The orebodies become thicker on the hinge zones and reversal limbs of the folds. Ratios of Fe/Ti-Al/(Al+Fe+Mn) and Co/Ni indicate its hydrothermal characteristics. In combination with the ore vein traverse relationship and ore textures and structures, the mineralization process can be divided into hydrothermal deposition period and the late epithermal transformation period. The ore-forming fluids are low in salinity, which indicates its evolution trend from low salinity to high salinity. It is concluded that the Yinshan silver polymetallic deposit is an epithermal hydrothermal one, and the Precambrian era is the stage of the enrichment of ore-forming elements, but it did not form economically valuable ores. The late tectonic movements and rock mass intrusion spawned the enriched ores.