What is the age of the earth's oil? Oil in the ground is found under the oceans and seas. It is made of dead fish. But from what period are those fish? I heard they are about 119 million years old. But fish exist much longer than that. So is it clear how old our oil is?
Oil can be generated from pretty much anything organic. The oldest oil that I know of comes from a porous Eocambrian siltstone in the Sultanate of Oman. This was formed nearly 200 million years before there were any fish around.
Apart from that, oil can be formed in any of the geological eras up to the late Cenozoic.