MACFLINCOR AND ITS APPLICATION TO FLUIDS IN ARCHEAN LODE-GOLD DEPOSITS

MacFlinCor was developed to process laboratory data gathered on fluid inclusions and to calculate isochores for geologically important fluid s composed of H2O, CO2, CH2, NaCl, and N-2. Within the program, intera ctive diagrams are available to describe those chemical systems which cannot be adequately constrained numerically. The user can choose from various published equations of state describing fluid behavior and ca n easily compare the results obtained by using different equations. Th e program, once the basic fluid parameters have been established, allo ws the data to be used to determine the P-T trapping conditions, to ev aluate possible pressure corrections and to compare different depths o f formation based on the pressure calculations and given geothermal gr adients. For illustrative purposes, MacFlinCor has been utilized here to constrain different physical-chemical parameters of fluid inclusion s trapped in ore-related quartz veins and breccias of Archean lode-gol d deposits in Western Australia. Inferred pressures from individual de posits show a wide range of values which may be due to post-entrapment modifications and/or observational uncertainties including estimation of liquid-vapor ratios.