THE CHARACTERISTIC AND ORIGIN OF ORE-FORMING FLIUD FROM MICRO-DISSEMINATED GOLD DEPOSITS IN YOUJIANG BASIN

Fluid inclusions from micro-disseminated gold deposits in Youjiang basin area are mainly liquid inclusions which are more than 90% in all inclusions in quantity. The physical and chemical features of the inclusions are as follow: low homogenization temperature, low salinity, high Na~+, low K~+, high Cl~- , low F~-, and 2Na~+/K~+10,1.5Na~+/(Ca~(2+)+Mg~(2+))4 which are not character of magmatic fluid and hot brine. Hydrogen isotope of samples vary in little range, whereas Oxygen isotopes vary in large range. On the figure of δD-δ~(18)O, the data distribute approximately along the line δD = -70‰ which represents evolving line of Mesozoic meteoric water in Southchina. In fluid inclusions,~(36)Ar came from atmosphere and Sr derived from crust. An above evidence indicates that the water in ore-forming fluids is mainly from meteoric water. In the process of mineralization of gold, meteoric water didn't infiltrate downward vertically in ore district, but infiltrated from south to north on basin scale.