安徽省东至县程檀金矿成矿流体地球化学研究

Study of ore-forming fluid geochemistry of Chengtan gold deposit in Dongzhi County of Anhui Province

东至县程檀金矿位于扬子陆块北缘,是一受构造控制的中低温热液蚀变矿床,金资源量具一定规模。根据流体包裹体地球化学研究显示:程檀金矿成矿阶段均一温度介于119.7℃~244.9℃之间,平均171.19℃;流体盐度w(NaCleq)介于0.18%~12.85%之间,平均4.15%;成矿压力变化范围为8.28Mpa^22.57MPa,平均13.57Mpa,对应成矿深度变化范围为0.33~0.9km,平均值为0.54km。根据碳、氢、氧同位素研究表明,成矿流体可能主要来源于岩浆岩,后期有大气降水参与。

Chengtan gold deposit is located at the north margin of Yangtze Block in Dongzhi County,which is a medium-low temperature hydrothermal alteration deposit controlled by structure.There is a certain scale of the gold resources in the deposit.According to the fluid inclusion geochemistry research,it is shown that the deposit metallogenic stage uniformity temperature is between 119.7℃ and 244.9℃,with an average value of 171.19℃.The fluid salinity is in the range of(0.18-12.85)(wt%)NaCleq,with an average value of 4.15(wt%)NaCleq.The ore-forming pressure varies between 8.28 Mpa and 22.57 Mpa,with an average value of13.57 Mpa.The corresponding range of mineralization depth is between 330 mand 900 m,with an average value of 540 m.According to the research of carbon,hydrogen and oxygen isotopic compositions,the oreforming fluid might come from magmatic rocks,and the meteoric precipitation water is involved into it in the later stage.