Characteristics of alteration and mineralization of the Shaxi porphyry copper deposit,Luzong area,Anhui Province
YUAN Feng1,ZHOU TaoFa1,WANG ShiWei1,FAN Yu1,TANG Cheng1,ZHANG QianMing2,YU CangHai3 and SHI Cheng3 1.School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China 2.No.327 Geological Team,Bureau of Geology and Mineral Resources of Anhui Province,Hefei 230001,China 3.Tongling Nonferrous Metals Group Holding Co.,Ltd.,Tongling 244000,China
Shaxi is a large porphyry copper deposit located outside the Luzong volcanic basin in the Middle and Lower Reaches of the Yangtze River metallogenic belt.Before this study,geological investigations of wall rock alteration and mineralization characteristics of the deposit were minor,restricting application of these guides to exploration and to further study of the metallogenesis of the region.On the basis of previous work plus our detailed field observations and petrographic and mineralogical studies,we have characterized the magmatic rocks and their sequence of intrusion,the mineralogy of alteration(alteration type:potassic alteration,propylitization,feldspar-destructive alteration and kaolinization) and its zoning(from deep to shallow:potassic alteration,feldspar-destructive alteration and kaolinization),the characteristics of mineralization,the sequence of mineral deposition and the ore-forming stages(potassium silicate stage,quartz sulfide stage and quartz carbonate stage;the quartz sulfide stage can be further divided into quartz sulfide sub-stage and epidote-chlorite sub-stage).Based on the characteristics of alteration and mineralization at Shaxi,we find that the chalcopyrite began to precipitate in the late stage of the potassium silicate alteration,and reached a peak during the quartz sulfide substage.The quartz carbonate stage also contributed some copper to the ore.The alteration and mineralization characteristics of Shaxi porphyry copper deposit are generally similar to porphyry deposits in different tectonic environments.The alteration zoning in Shaxi deposit is similar to that in deposits in continental marginal arcs and island arcs,and intracontinental collision post-orogenic extension environments,but the alteration at Shaxi is different from that at Dexing deposit,which occurs in an intraplate setting,but the ore types and mineralization are similar.Consequently,the tectonic setting may control the formation and evolution and the ore-bearing potential of magma,but the final emplacement depth of the magmatic rocks and the nature of their wall rocks control the alteration and mineralization characteristics of porphyry deposits.
【Fund】： 国家自然科学基金项目(40830426、41172084、41172086);; 中国地质调查局地质调查工作项目(1212011121115);; 国家“深部探测技术与实验研究专项计划”专题(SinoProbe-03-02-05);; 安徽省国土资源科技项目(2009-g-22 2011-g-11);; 新世纪优秀人才支持计划项目(NCET-10-0324)联合资助
【CateGory Index】： P618.41
【CateGory Index】： P618.41