"After all these superstar/supernova/superstar/supernova cycles, one would expect that the atoms of the various elements would be pretty well stirred-up and randomly distributed. Where, then, did gold nuggets and iron meteoroids come from?"
Most of that geology I can accept, given the melting and crustal movements. But, admittedly, coordinating the simultaneous explosions of 10^40 supernova's is a bit tough.
8<)
And, as stated, today's physics and mass-energy do a pretty good job of explainig what's happening right now.