PRELIMINARY STUDY ON THE MINEROGENETIC MODEL OF MESOZOIC VOLCANIC-MAGMATIC ROCKS IN EASTERN JILIN,CHINA

The Mesozoic continental volcanic fault basin in Eastern Jilin is tectonically located in Yanbian synclinorium of Yanbian eugeosyncline fold belt.Since Mesozoic,faults with different directions,intense volcanic activities and frequent magma intrusions have been developing in this area.Gold,copper and polymetal deposits,as well as mineralizing alterations,which are genetically related to the Mesozoic volcanic magmatic activities,are commonly seen,forming the well known E-W-trending Wufeng-Xiaoxinancha post-volcanic magmatic stage epithermal Au-Cu-polymetal metallogenic belt.The Mesozoic volcanic-magmatic rocks in the region are the result of mantle magma intrusion,accompanied by mineralization,with Au-Cu-polymetal orebodies formed in favorable structural positions.The ore-forming matters are derived from the mantle.The mineralization took place in acid media under a reduction condition.From far source to near source,with the mineralizing zonation of Au,Ag→Au,Cu,Ag→Cu,Au,Pb,Zn→Cu(Mo,Au),the ore-forming temperatures change from low to high;while the sulphide contents vary from poor to abundant.