* Plant Material: Swamps and bogs provide the perfect environment for the growth of dense vegetation, primarily trees and ferns.
* Anaerobic Conditions: The waterlogged conditions in these areas lack oxygen, creating an anaerobic environment which inhibits the decomposition of the dead plant material.
* Burial and Compression: Over time, layers of sediment accumulate on top of the plant debris, burying it and applying immense pressure.
* Transformation: This pressure and the heat from the Earth's interior transform the plant material into peat, which then further transforms into coal over millions of years.
So, while coal is ultimately found in the Earth's crust, it forms in specific environments within the crust - the swamps and bogs where the necessary conditions exist.
