Yes the question was answered. River actually answered it. I honestly think that there will be something more to do with Trenzalore because there were no fields at all it was a complete graveyard. I think that we will see a revisit to Trenzalore with the question being asked again, I think that is what will start everything that turns Trenzalore into what it was in that episode.
I think the only reason there was no mention of the silence was because the Great Intelligence was at Trenzalore.