Coal is a fossil fuel that has been used for centuries to generate heat and energy. It is believed to have formed millions of years ago during the Carboniferous period, also known as the “Coal Age”. In this article, we will explore how coal was formed in ancient times.
What is coal?
Coal is a black or brownish-black sedimentary rock that is primarily composed of carbon. It is formed from the remains of plants that lived and died millions of years ago. These plants were buried under sediment and rock and subjected to high pressure and temperature over time, causing them to transform into coal.
How was coal formed?
During the Carboniferous period, vast swamps covered much of what is now Europe and North America. These swamps were home to large trees, ferns, and other vegetation. As these plants died, they fell into the swampy water and were quickly buried by sediment.
Over time, more layers of sediment piled on top of the dead plant matter. The weight of this sediment compressed the plant material, squeezing out water and gases. As the pressure continued to increase, chemical changes occurred within the plant material, turning it into peat – a soft, brownish material that resembles modern-day compost.
As more layers of sediment accumulated on top of the peat, it became buried deeper beneath the Earth’s surface. The increasing pressure and temperature caused further chemical changes to occur within the peat, transforming it into different types of coal – lignite, bituminous coal, anthracite – depending on its composition and geological conditions.
The types of coal
- Lignite: This is the lowest grade of coal with a low carbon content (25-35%) and high moisture content.
- Bituminous: This is the most common type of coal with a carbon content ranging from 45-85% and a relatively low moisture content.
- Anthracite: This is the highest grade of coal with a carbon content of 86-97% and very low moisture content. It is also the hardest and shiniest type of coal.
In conclusion, coal was formed millions of years ago during the Carboniferous period from the remains of plants that were buried under sediment and subjected to high pressure and temperature over time. The different types of coal – lignite, bituminous, and anthracite – were formed depending on their composition and geological conditions. Today, coal continues to be an important source of energy for electricity generation and other industrial processes.