Coal is a solid, black, readily combustible fossil fuel that contains a large amount of carbon-based material – approximately 50% of its weight. The formation of coal takes a significant amount of time (on the order of a few million years), and the first coal-bearing rock units appeared about 290-360 million years ago, at a time known as the Carboniferous or “coal-bearing” Period. As well, there are extensive coal deposits from the Cretaceous age – about 65 to 144 million years ago.
The formation of coal begins in areas of swampy wetlands where groundwater is near or slightly above the topsoil. Because of this, the flora present produces organic matter quickly – faster in fact than it can be decomposed. In these areas, layers of organic matter are accumulated and then buried. It is these layers of organic material that then form coal. The energy in coal initially comes from the sun and is energy from sunlight trapped by dead plants(Coal Formation – Energy Education, n.d.).
What’s another common natural resource whose formation process you find incredibly complex or surprising? Share your thoughts below!
