How coal was formed

Coal was formed in Paleolithic era ecosystems ( lake basins, river deltas or low lying areas ) and is made of the material of prehistoric plants. Initially, through solar energy they produced hydrocarbons from air, water and mineral matters. Upon decay they sank into the swamps which were environments without oxygen. They could not decompose by normal biological processes. Evidence of this origin of coal and specific structure of prehistoric ecosystems can be found in numerous palaeontological findings.

Further geological processes then overlaid the layers of biologic origin with other materials – often suddenly as a result of various natural disasters. It is evidenced by the transitions between the coal seam and the surrounding rock being frequently very sharp.

The matter initially similar to turf gradually got deeper and thicker. Owing to increasing pressures and temperatures water and other substances were displaced from it while the share of carbon was built up.

The conversion of biological material to coal can be expressed by this simplified equation:

biological material (cellulose) = carbon dioxide + water + methane + carbon (coal)

It is indicated that for the formation of a coal seam of one metre thickness approximately 100 m layer of turf was needed. Thus, the longer this process took, the superior the coal is – the most pure and final product of carbonization is graphite (black-lead) with virtually 100% carbon content.

The greatest and the best coal seams were formed in the Palaeozoic era called Carboniferous indicatively, which era also includes the period of the formation of Ostrava-Karviná coal. Coal was further formed in the Palaeozoic era called Permian and even later. However, with shorter periods of carbonization the quality of coal decreases – in other words: not only wine and whisky age to perfection.

Coal is being formed in Paludal ecosystems even today, thus a skilful lawyer would not be in a hopeless position trying to declare coal as a constantly renewable source of energy. Nevertheless, the raw material being formed today will be of use to our posterity in tens or hundreds of millions of years.

Anorganic origin of coal?

Rather as an amusing oddity it is worth mentioning that there is a view according to which coal was not formed from biological material but it is of anorganic origin.