How was crude oil formed?
Crude oil was formed from the remains of animals and plants (diatoms) that lived millions of years ago in a marine environment before the existence of dinosaurs. Over millions of years, the remains of these animals and plants were covered by layers of sand, silt, and rock. Heat and pressure from these layers turned the remains into what we now call crude oil. The word petroleum means rock oil or oil from the earth.
Source: U.S. Energy Information Administration (public domain)
Diatoms magnified under a microscope.
Source: Image used by permission from Micrographia
Last updated: December 11, 2018