STUDY ON THE METALLOGENIC FEATURE AND ORE GENESIS OF WANZHUANG GOLD DEPOSIT,BEIJ ING

Wanzhuang gold deposit is distributed in the Midproterozoic ca rbonate strata of the Yanshan depression zone within the Sino-Korean platform. G old mineralization is controlled by the Yan- shanian period Sanbaishan intr usive, metamorphosed strata, interformational breccia zones and NE-striked fract ures with multi-period of activities. Gold ore bodies in Wanzhuang gold deposit occur as chimney, pillar and vein forms. The main ore minerals are limonite, pyr ite, native gold, and electrum. Ore types are mainly silicalized poly-metallic a nd silicalized pyrite types. In the mining area, horizontal mineralization zonat ion is obvious. Taking Sanbaishan intrusive as the center outwardly through inne r contact zone to outer contact zone and the metamorphic wall rocks, mineraliza tion types change from hydrothermal vein type Cu mineralization to skarn type Cu -Au mineralization to hydrothermal gold mineralization. The first two types of m ineralization are of no industrious significance while the third ore forms Wanzh uang gold deposit. Various pieces of evidence shows that the basement rocks of the Archean Miyun group provided some ore-forming materieds and the Sanbaishan q uartz diorite intrusive and related dykes could be the source for heat and part of the ore-forming hydrothermal fluid that mixed with meteoric water during gold mineralization. And the Midproterozoic carbonate rocks were the favourable wall rocks for gold mineralization. From all above, it is recognized that Wanzhuang gold deposit belongs to the type of middle to low temperature gold deposit with obvious stratabound characteristics.