【摘要】 富湾超大型银矿床主要为脉状,产于下石炭统灰岩与长坑赋金硅质岩接触带及其下的破碎带中。银矿床矿化石英40Ar-39Ar年龄为(64.3±0.1)Ma。矿床铅同位素μ值(10.67~10.95)与赋矿地层的μ值(9.79~10.33)不同,而与粤西地区元古宇基底中矿床的μ值(10.62~10.66)相似。富湾超大型银矿床成矿物质主要来自元古宙变质基底,矿床形成与三水盆地晚白垩世到早第三纪强烈火山活动形成的有利成矿环境有关。有利于形成富湾超大型银矿床地质条件包括:(1)深大断裂构造交汇及盆地边缘同生断裂构造组成的连通网;(2)特殊岩性组合形成的聚矿-圈闭环境;(3)丰富成矿物质源区、多期矿化及成矿元素多次活化迁移;(4)多期次火山活动形成的循环地热系统。更多还原

【Abstract】 The Fuwan superlarge silver deposit is hosted in the Early Carboniferous limestones along a contact fault zone between the limestone and the overlying Changkeng Au-hosting siliceous rocks. The ~ 40 Ar-~ 39 Ar age of the ore-related quartz veins from the Fuwan silver deposit is (64.3±0.1) Ma. The silver deposit is characterized by high μ values (10.67~10.95) in Pb isotopic composition, being much higher than those of the Paleozoic ore-hosted strata and being similar to those of ores hosted in Preterozoic metamorphic base in the Western Guangdong Province. It is concluded that the ore-forming material of the superlarge silver deposit came primarily from the Proterozoic basement. The superlarge silver deposit owns its origin to the Himalayan volcanic activities in the region of the Sanshui Basin.The formation of Fuwan superlarge silver deposit is controlled by the following favorable geological conditions: The intersection of deep faults and contemporaneous faults at the margins of the Sanshui Basin served as excellent passageways for ore fluids; the special ore-hosted rock association served as the ore-concentration and ore-trapping structures; the silver-rich basement,multiple stages of mineralization and of mobilization of silver and related elements; geothermal convection system related to multiple episodes of volcanic activities.更多还原