摘要
Fluid inclusion studies of 5 gold deposits connected with alkaline rocks show that quartz separated from auriferous quartz veins contains abundant three\|phase CO\-2\|NaCl\|H\-2O inclusions and two\|phase CO\-2\|dominated ones, measuring 5-20μm in diameter. Homogenization temperatures of the fluid inclusions are mostly within the range of 150-300℃, and the salinities, mainly 0.2wt%-12 wt%(NaCl). Gold mineralizations occurred at depths of 1.4-2.8 km. The most striking character of fluid composition is that among the cations, Na\++ is dominant, followed by K\++, Ca\+\{2+\}; among the anions, Cl\+- is slightly higher than SO\+\{2-\}\-4. In the evaporate, H\-2O is dominant, followed by CO\-2. The pH values are mainly within the range of 6.5-8.5,indicating that the ore\|forming solutions are alkaline in nature. The hydrogen and oxygen isotopic ratios indicate that the ore fluid is composed mainly of magmatic water. With the dropping of temperature in the ore fluid, the contents of CO\-2 decreased while the salinity increased. The relations between Au and other components of the ore fluid are discussed in the paper, and it is concluded that in these deposits, chlorides, H\-2S, SiO\-2,CO\-2 , etc. in the fluid all are involved in the migration and concentration of Au.
Fluid inclusion studies of 5 gold deposits connected with alkaline rocks show that quartz separated from auriferous quartz veins contains abundant three\|phase CO\-2\|NaCl\|H\-2O inclusions and two\|phase CO\-2\|dominated ones, measuring 5-20μm in diameter. Homogenization temperatures of the fluid inclusions are mostly within the range of 150-300℃, and the salinities, mainly 0.2wt%-12 wt%(NaCl). Gold mineralizations occurred at depths of 1.4-2.8 km. The most striking character of fluid composition is that among the cations, Na\++ is dominant, followed by K\++, Ca\+\{2+\}; among the anions, Cl\+- is slightly higher than SO\+\{2-\}\-4. In the evaporate, H\-2O is dominant, followed by CO\-2. The pH values are mainly within the range of 6.5-8.5,indicating that the ore\|forming solutions are alkaline in nature. The hydrogen and oxygen isotopic ratios indicate that the ore fluid is composed mainly of magmatic water. With the dropping of temperature in the ore fluid, the contents of CO\-2 decreased while the salinity increased. The relations between Au and other components of the ore fluid are discussed in the paper, and it is concluded that in these deposits, chlorides, H\-2S, SiO\-2,CO\-2 , etc. in the fluid all are involved in the migration and concentration of Au.
