Oxygen isotope exchange between quartz and water

Equilibrium constants for oxygen isotope exchange between quartz and water have been measured from 195°C (1000 ln α = 12.0) to 750°C (1000 ln α = 0.4). Over limited temperature ranges the behavior of fractionation with temperature can be approximated by 1000 ln α = 3.38 (106 T−2) − 3.40 for 200°–500°C and by 1000 ln α = 2.51 (106 T−2) − 1.96 for 500°–750°C. The results of measurements in the quartz-water system can be combined with analogous results from other mineral systems to make mineral-pair isotopic thermometers for application to problems of petrogenesis.