延边东北部地区中生代火山-岩浆岩区金铜矿成矿特征

METALLOGENIC CHARACTERISTICS OF GOLD AND COPPER DEPOSITS IN MESOZOIC VOLCANIC-MAGMATIC AREA IN NORTHEASTERN YANBIAN

延边东北部地区中生代陆相火山断陷盆地处于吉黑褶皱系延边优地槽褶皱带延边复向斜内 ;区内中生代以来不同方向的断裂发育 ,火山活动强烈 ,岩浆侵入频繁 ;与中生代火山 -岩浆活动有成因联系的金、铜金金属矿床多处 ,矿化蚀变线索也较多 ,构成了著名的五凤 -小西南岔近东西向火山 -岩浆期后低温热液型金、铜多金属成矿带 ;区内中生代火山 -岩浆岩的形成是太平洋板块俯冲作用使大陆边缘拉张活动不断加剧 ,造成上地幔岩浆上侵的结果 ;并伴有成矿作用的发生 ,在岩浆岩体内外接触带的有利部位形成金、金铜或铜金多金属矿床 ;从远源至近源的成矿分带为Au- Ag→ Au- Cu- Ag→ Cu- Au- Pb- Zn→ Cu (- Mo- Au) ;成矿作用表现出从低温至高温、从低硫到高硫的变化 .

The Mesozoic continental volcanic fault basin in the northeast area of Yanbian is located in Yanbian synclinorium of Yanbian eugeosyncline folding zone Since Mesozoic, faults with different directions, strong volcanic activities and frequent magma intrusions have been developing in this area There are occurred many copper polymetal deposits which are genetically related to Mesozoic volcanic magmatic activity The mineralized alteration can be commonly found,forming the famous Wufeng Xiaoxinancha post magmatic epithermal type of Au Cu polymetal mineralized belt striking E W The Mesozoic volcanic magmatic rocks of the area resulted from the underthrust of the Pacific plate which made the intense extension of continental margin and upward intrusion of upper mantle magma accompanied by mineralization Au,Au Cu or Cu Au polymetal deposits formed in favourable places of inner and outer contact zone in magmatic body.From distal to proximal, metallogenic zoning is Au, Ag→Au, Cu, Ag→Cu, Au,Pb,Zn→Cu(Mo,Au) The mineralization shows a process from low temperature to high temperature and from low sulphur to high sulphur