I’ve actually assumed for a long time that some ‘bug’ must make oil...probably microscopic in size.
Why?
1. Purity. Oil is supposedly plant and animal matter that just ‘decomposed’. Wouldn’t that mean that somewhere along the way, some petrified wood, a sliver of bone, or fibrous plant material would show up, with all the oil we’ve pumped? Since that doesn’t happen, wouldn’t oil’s homogeneous nature imply that some process is sythesising the decaying matter?
2. Free Carbon. On a macro scale, the problem with burning fuel isn’t really the CO2, as much as the O2. Once the carbon joins with the oxygen, there are not many processes in nature that split the two back again...and concievably, we could lower the oxygen content of air. Sure plants split them - but ultimately most are ‘used’ in a way that joins its carbon back to oxygen - you eat wheat for example, your body burns it, and you breath out CO2, same goes for burning wood, etc. So, we have vast reserves of carbon below ground, which could potentially join with all our oxygen and suffocate us all...and its very good that the O2 is above ground, and the carbon is seperate below ground. But how did the carbon seperate itself in the first place? I believe some process had to have performed this task...and micsoscopic bugs nibbling at decaying plants is not a stretch. Similar concepts are used in water treatment, and have been for years.
Now why haven’t we seen these ‘bugs’. Maybe something changed in our atmosphere, and they went the way of the dinosaurs.
I know it sounds whacky...but really, does the ‘decayed plant and animal life’ sound that plausible?
Temperature and pressure, most likely, with the passage of sufficient time.