  We show that, by treating the gravitational interaction between two
mechanical resonators as a classical measurement channel, a gravitational
decoherence model results that is equivalent to a model first proposed by
Diosi. The resulting decoherence model implies that the classically mediated
gravitational interaction between two gravitationally coupled resonators cannot
create entanglement. The gravitational decoherence rate ( and the complementary
heating rate) is of the order of the gravitationally induced normal mode
splitting of the two resonators.
