浅成低温热液矿床特征及在我国的找矿方向
CHARACTERISTICS OF EPITHERMAL DEPOSITS AND THE PROSPECTING GUIDE IN CHINA
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摘要: 浅成低温热液矿床形成的构造环境主要为岛弧和岛弧之后的张裂带,大多数形成于第三纪,少数矿床形成于中生代和古生代.矿石具脉状、网脉状和角砾状构造,发育有特征的矿物组合、元素分带.围岩具特征的蚀变分带.矿化围岩主要为分异良好的火山岩类.矿床形成于地表以下1000 m深度范围内,成矿温度一般为200~300℃,成矿流体以低盐度的大气降水为主.结合我国浅成低温热液矿床的形成条件分析,提出该类矿床在中国的有利成矿区.Abstract: The tectonic backgrounds of epithermal deposits are mainly island arc and arc-back extension belt. Most deposits of the type are formed in Cenozoic, with minority in Mesozoic and Palaeozoic. The structure of ore are of vein, stockwork and breccia. The ore bodies are charaterized by specific mineral assemblage, element belting and alteration zoning. The mineralization occurs in volcanic terrane that fractionate well. The mineralization depth is less than 1000 m. The mineralization temperature is in the range of 200~300℃. The hydrothermal brine is dominated by low-salinity atmosperic precipitation.Based on the analysis for the condition of epithermal deposit formation in China, the authors propose favorable areas of mineralization in China.