What is coal & how does it form?
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Coal is a black or brownish-black sedimentary rock that is primarily composed of carbon and other elements such as hydrogen, sulfur, oxygen, and nitrogen. It is a valuable energy source that is widely used for electricity generation and industrial processes.
Coal forms from the remains of plants that lived and died millions of years ago. The formation process begins with the accumulation of plant material in swampy areas. Over time, layers of dead plants, known as peat, build up. The peat is then subjected to high pressure and temperature, causing physical and chemical changes. These changes, known as coalification, gradually transform the peat into different types of coal.
There are four main types of coal: lignite, sub-bituminous, bituminous, and anthracite, which differ in their carbon content and energy content. Lignite, the lowest grade coal, contains about 25-35% carbon. Sub-bituminous coal has a higher carbon content of around 35-45%. Bituminous coal, the most commonly used type, contains about 45-86% carbon. Finally, anthracite is the highest grade coal, with a carbon content of over 86%.
To learn more about the formation of coal and its different types, you can visit the link http://www.athro.com/geo/trp/gub/coal.html. This resource provides a detailed explanation of the coal formation process, including the stages of coalification and the factors that influence coal quality.