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龙头山金矿是钦杭成矿带南段大瑶山地区重要的金矿床之一,矿区发育大量不同阶段的黄铁矿,根据其产出特征和先后关系划分为5个世代,对应着5个成矿阶段:电气石-石英-硫化物阶段(Ⅰ)、石英-黄铁矿-黄铜矿阶段(Ⅱ)、石英-多金属硫化物阶段(Ⅲ)、石英-黄铁矿-闪锌矿阶段(Ⅳ)和石英-黄铁矿阶段(Ⅴ)。黄铁矿单矿物的稀土、微量元素分析结果表明:与金成矿有关的成矿流体主要为中高温岩浆热液,具有还原性,且流体富Cl-贫F-,Au主要以(AuCl_2)~-络合物形式迁移。黄铁矿δ~(34)S_(CDT)值介于+1.29×10~(-3)~+2.01×10~(-3),表明成矿物质来源于深部岩浆;铅同位素μ值为9.63~9.84,Th/U值为3.87~4.00,变化范围窄,为稳定性铅同位素。综合分析认为:矿区成矿物质主要来源于基底地壳重熔形成的深部岩浆岩,其中岩浆期后热液为主要成矿热液。
Longtoushan gold deposit is one of the important gold deposits in Dayaoshan area in the southern segment of Qinhang metallogenic belt. There are a large number of different stages of pyrite in the mining area, which are divided into 5 generations according to their output characteristics and their relationship, corresponding to 5 Stage of the ore: tourmaline-quartz-sulphide stage (I), quartz-pyrite-chalcopyrite stage (II), quartz-polymetallic sulphide stage (Ⅳ) and quartz-pyrite stage (Ⅴ). The results of REE and trace element analysis of single minerals in pyrite indicate that the ore-forming fluids related to gold mineralization are mainly medium- and high-temperature magmatic hydrothermal fluids with reducibility and rich Cl- Complex form migration. The δ ~ (34) S_ (CDT) value of pyrite ranged from + 1.29 × 10 -3 to + 2.01 × 10 -3, indicating that the ore-forming materials originated from deep magma. The Pb isotopic value of pyrite was 9.63 ~ 9.84, Th / U value of 3.87 ~ 4.00, a narrow range of variation, as a stable lead isotope. The comprehensive analysis shows that the ore-forming materials in the mining area are mainly derived from the deep magmatic rocks formed by remelting of the basement crust, and the hydrothermal fluids are the major hydrothermal fluids after the magmatic period.