How are fossil fuels formed?

Dead plants and animals settle in swamps, oceans, or lakes. This organic material accumulates faster than it can decompose.

Over time, layers of sediment (like mud, sand, and rock) cover the organic matter. This burial creates an anaerobic (oxygen-free) environment, preventing complete decomposition.

As more layers accumulate, the buried organic matter is subjected to immense heat and pressure from the overlying sediments and the Earth's internal heat. This process transforms the organic material.

• Coal forms from terrestrial plant matter, typically in swampy environments.
• Oil and natural gas form from marine organisms (plankton and algae) in ocean basins.

This slow transformation, occurring over millions of years, converts the organic matter into hydrocarbons, which are the chemical compounds that make up fossil fuels.