Earth after life

[mith]

Iron oxidation(rust), etc...

[Balanchine]

Right, good point. I also found this from a general article on bacteria, which answers quite a bit of my earlier question:

"Bacteria are solely responsible for the 20% of the atmosphere that is oxygen, which is a highly reactive gas that took millions of years of evolution to harness correctly. If there was a way to kill all bacteria, the amount of oxygen on Earth would drop to zero, as it literally floats right out of the atmosphere and must be created constantly. While plants definitely play a role, they themselves could not exist without bacteria."