This paper presents the temperature and pressure dependence of the minimum binary diffusivity in granitic melts. The minimum diffusivities are determined by monitoring the temporal development of the diffusion -controlled melt layer(DCM) in granitic systems (albite (Ab) -quartz (Qtz) -H 2 O and orthoclase (Or) -Qtz -H 2 O) gathered during 31 melting experiments under conditions of 800 -900 °C and 100 -200 MPa for durations of 19 -72 h. The DCM is formed between single crystals (Ab or Or crystals) and powdered quartz in all runs and is characterized by a distinct concentration gradient. The maximum thickness of the DCM increases systematically with temperature, pressure, and run duration. Temporal development of the DCM obeys the parabolic growth rate law, using which the diffusivity can be estimated. Plots of concentrations along the diffusion paths in ternary diagrams (Na 2 O -Al 2 O 3 -SiO 2 diagram for the Ab -Qtz -H 2 O system and K 2 O -Al 2 O 3 -SiO 2 diagram for the Or -Qtz -H 2 O system) show linear trends rather than S -shaped trends, indicating that binary nature of diffusion occurs in these systems. Therefore, the diffusive component can be interpreted as an albite component or orthoclase and quartz components (SiO 2 ) rather than an oxide or a cation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.