Section-2 Formation and Stages

Different stages of coal

We all know different types of coal, but do we know what is the difference?

COAL FORMATION

The majority of fossils recovered in Cape Breton can be traced to coal areas or coal fields. Fossils have been found ranging from whole or partial tree trunks and branches to shrubs and vine growth. Evolution dates back to pre-historic times – to approximately 325 million years ago when the region was covered in lush, dense vegetation.

Coal beds consist of altered plant remains. When forested swamps died, they sank below the water and began the process of coal formation. However, more than a heavy growth of vegetation is needed for the formation of coal. The debris must be buried, compressed and protected from erosion. Even though all the biological, geographic and climatic factors may be favourable, coal could not be formed unless the plant debris was submerged and buried by sediments.

There are four stages in coal formation: peat, lignite, bituminous and anthracite. The stage depends upon the conditions to which the plant remains are subjected after they were buried – the greater the pressure and heat, the higher the rank of coal. Higher-ranking coal is denser and contains less moisture and gases and has a higher heat value than lower-ranking coal.