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棉田金铜矿床是受断裂构造和中性侵入体联合控制的以金、铜为主的多金属矿床。笔者在对该区地质调查的基础上,运用红外光谱分析和显微测温技术对成矿流体进行研究,发现该区围岩蚀变以绢云母化和青磐岩化最为普遍,并将成矿阶段分为4个阶段:黄铁绢英岩阶段、石英--黄铁矿阶段、多金属硫化物阶段和石英--碳酸盐阶段;对应的均一温度为320℃～360℃、280℃～320℃、200℃～280℃和200℃～240℃;其中主成矿阶段为第二、三阶段,主成矿温度为200℃～320℃,这也是热液中水和二氧化碳含量最高的阶段。流体盐度为1.91～13.40(wt%,NaCl),密度为0.69～0.95g/cm3,具低盐度和低密度的特点;成矿深度为0.8～1.5 km,具浅层成矿的特点;氢氧同位素分析,δ18OH2O的值为-4.7×10-3～5.83×10-3,δDH2O的值为-89×10-3～-124×10-3,说明成矿流体主要为岩浆水,含少量大气水。综合研究表明,棉田金铜矿床属于浅成中温岩浆热液型矿床。
The gold-copper deposit in cotton field is a polymetallic deposit dominated by gold and copper under the combined control of fault structure and neutral intrusion. Based on the geological survey in this area, the author studied the ore-forming fluids by infrared spectroscopy and microscopic temperature measurement. It is found that the alteration of wall rocks in the area is most prevalent with sericitization and metamorphism and mineralization The stage is divided into four stages: pyroxene-quartzite stage, quartz-pyrite stage, polymetallic sulphide stage and quartz-carbonate stage; the corresponding homogenization temperature is 320 ℃ ~ 360 ℃, 280 ℃ ~ 320 ℃ , 200 ℃ ~ 280 ℃ and 200 ℃ ~ 240 ℃. The main mineralization stage is the second and third stages, the main mineralization temperature is 200 ℃ ~ 320 ℃, which is also the hydrothermal water and carbon dioxide levels of the highest stage. The salinity of the fluid is 1.91 ~ 13.40 (wt% NaCl) and the density is 0.69 ~ 0.95g / cm3, with low salinity and low density. The mineralization depth is 0.8 ~ 1.5 km with the characteristics of shallow mineralization. Hydrogen and oxygen isotope analysis, δ18OH2O value of -4.7 × 10-3 ~ 5.83 × 10-3, δDH2O value of -89 × 10-3 ~ -124 × 10-3, indicating that the ore-forming fluid is mainly magmatic water, containing A small amount of atmospheric water. The comprehensive study shows that the gold-copper deposit in cotton field belongs to epithermal magmatic hydrothermal deposit.