  We apply our theory of conservative solute transport, based on concepts from
percolation theory, directly and without modification to reactive solute
transport. This theory has previously been shown to predict the observed range
of dispersivity values for conservative solute transport over ten orders of
magnitude of length scale. We now show that the temporal dependence derived for
the solute velocity accurately predicts the time-dependence for the weathering
of silicate minerals over nine orders of magnitude of time scale, while its
predicted length dependence agrees with data obtained for reaction rates over
five orders of magnitude of length scale. In both cases, it is possible to
unify lab and field results. Thus, net reaction rates appear to be limited by
solute transport velocities. We suggest the possible relevance of our results
to landscape evolution of the earth's terrestrial surface.
