Geochemistry of subvolcanic-type copper-silver deposits in eastern China

The metallogenesis of subvolcanic deposits is controlled by subvolcanic act ivities. The copper polymetallic deposits are genetically related to interm ediate-acid rocks, and the silver polymetallic deposits are more closely re lated to acid rocks. The abundance of Cu is relatively high in the intermed iate-acid rocks and subvolcanic rocks, whereas the abundances of Pb, An and Ag are high in acid rocks, indicating rich ore-forming elements in origina l magmas. The study of REEs shows that the magmatic type related to copper deposits is the syntectic type, and that related to silver polymetallic dep osits is mainly the re-melting type. The deposits were formed under medium- low temperatures and low salinity. The metallogenic times were the late sta ge of the early Yanshanian or the late Yanshanian, dating 78-147 Ma.