Confusion about "mass reacted" in Gtplot

[ats5482]

Hi,

I'm using React to run dissolution experiments of minerals under Archean seawater conditions. In Gtplot, I noticed that for all of my model runs, plotting "mass reacted" (of the primary mineral) vs Rxn Progress shows a straight line that ends when the y-coordinate reaches the input mass. For example, if I run

react 100 g Anorthite

and plot "Mass reacted, Anorthite (g)" vs Rxn progress, the line goes from 0 to 100 g (see attached plot).

Does this mean all 100 g have been dissolved and are now in solution with no primary mineral remaining? Or can React model a dynamic equilibrium where, for example, you have seawater sitting on top of a crust (made of feldspar, olivine, etc) and the crust dissolves until it reaches saturation?