Calling all smart asses: Dinosaur/human coexistence question...

OK, you know the way dinos are found in rock strata several meters into the ground (or whatever). Well could it be possible that there was once a great flood, i.e., torrential rains which fell everyday for years, and caused the ground everywhere to become meters upon meters of thick, soggy, muddy wasteland?

Now, just wondering: considering the fact that dinosaurs (most of them) weighed several tonnes, isn't it likely that their huge bulk would have caused them to sink deeper into the ground compared to animals which weighed far less? So, therefore, dinos and humans may have actually coexisted, but the dinos may have sunk further into the earth during the great flood because of their huge bulk?

See, I'm not a creationist or nothing like that, but I just find it strange that dinosaur fossils (so many of them) are so well preserved when they are dug up. Shouldn't they have decayed into oblivion after so many millions of years?

Also I'm aware of the fact that scientists use radiometric dating to determine the age of the rocks in which fossils are found, and they do this by measuring the half-lives of radioactive isotopes within the rock. But could it be possible that the rock - in which these isotopes are found - had at one time partially liquefied due to continuous flooding, and the big ass dinos sunk into it?