Diffusion of oxygen in melts and minerals

It has been observed that water dramatically enhances oxygen diffusion in silicate melts as well as in many crystalline silicates. Furthermore, in systems studied in more detail, it has been observed that the diffusivity is roughly proportional to H2O pressure (Farver and Yund, 1990), or H2O content in the phase. This has been 

Assuming H20m is the diffusing species, the diffusion equation for R = 0  

Therefore, given an expression of how varies as a function of H20t con- 

In the above discussion, diffusion is considered to be the rate-limiting step, whereas the kinetics of the exchange reaction between different species 

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