FREEZING-POINT DEPRESSION OF NACL-KCL-H2O SOLUTIONS

Experimentally determined freezing points of NaC1-H2O and KC1-H20 solutions obtained in this study agree closely with previously published values, except for those data of Potter et al. (1978) above ∼13 wt percent NaCI. Owing to the agreement between our measured cutcctic temperature for NaC1-H2O (-21.21°C) and values determined by other workers and indicated by synthetic fluid inclusions, we believe that our data are more accurate than the earlier results of Potter et al. (1978) for freezing point depressions of NaCl-H2O solutions and should be used to determine salinities of aqueous fluid inclusions. If the NaCl/(NaC1 + KC1) wt ratio of the inclusion fluid can be determined through microanalysis, our equation (3) or the computer program listed in the Appendix may be used to determine the total salinity of the inclusion for a given freezing point depression.