Abstract
Experimental studies on the partitioning of Sr and Mg between gypsum and aqueous solutions indicate that partition coefficients depend on salinity: the partition coefficient for Sr increases with an increase in salinity while that for Mg decreases. In the low salinity region (ca.1-5 times salinity of seawater) the partition coefficient values obtained by this study are in agreement with those of the previous study by Kushnir (1980), but the values for the high salinity region (10-30 times seawater) are different from the previous ones. This difference could be explained in terms of influence of water activity. Using the analytical data on gypsum from low-temperature deposits (evaporite), the partition coefficients for gypsum from low-temperature deposits were calculated. The calculated values for Sr for large crystal gypsum are lower than the experimental values, suggesting that gypsum from low-temperature deposits precipitated more slowly than the experimental gypsum.
