The effect of presure on the solubility of minerals in water and seawater can be estimated from In ( KPsp K0sp) + (-ΔVP + 0.5ΔKP2) RT where the volume (ΔV) and compressibility (ΔK) changes at atmospheric pressure (P = 0) are given by ΔV = V ̄(M+, X-) - V ̄[MX(s)]ΔK = K ̄(M+, X-) - K ̄[MX(s)] Values of the partial molal volume ( V ̄) and compressibilty ( K ̄) in water and seawater have been tabulated for some ions from 0 to 50°C. The compressibility change is quite large (~10 × 10-3 cm3 bar-1 mol-1) for the solubility of most minerals. This large compressibility change accounts for the large differences observed between values of ΔV obtained from linear plots of In Ksp versus P and molal volume data (Macdonald and North, 1974; North, 1974). Calculated values of KPsp Kosp for the solubility of CaCO3, SrSO4 and CaF2 in water were found to be in good agreement with direct measurements (Macdonald and North, 1974). Similar calculations for the solubility of minerals in seawater are also in good agreement with direct measurements (Ingle, 1975) providing that the surface of the solid phase is not appreciably altered.
ASJC Scopus subject areas
- Geochemistry and Petrology