Is it possible that earth had naquadah in the past but was striped down before the the goa'uld left earth?
I would doubt that. Because that could had been mentioned Moebius, Part 1 and Moebius, Part 2 and Stargate: Continuum.
It could have been stripped of it before the Ancients left Earth
For all we know the Ancients could have used it all up building the gates.
What do you think?