[xcamel]

Half a billion years of single and small multicell carcases building up 2 mile deep sediments probably was the source of most of it.

[chuckles]

Well, NASA said the depth of the moon dust would be several hundred feet deep after billions of years of dust settling. In fact it was inches. Your scenario is widely accepted, but more and more scientists are looking for other theories.

Your scenario would mean that the earth would be covered in oil. No place would be without oil. A 2 mile deep pile of carcases would make us drown in oil. There are unanswered questions and anomalies with your assumptions.

One good thing about your theory is we could kill all the Chinese and make enough oil from the bodies to run for many years. A billion or so bodies converted to oil would save the polar bears for a few more years. Kinda a win win don't ya know. The UN could decide who lives and who dies. Finally the UN has a usefull purpose.