|MadSci Network: Environment/Ecology|
Fossil fuels are manís main source of energy in the past century and are: coal and lignite (a soft sub-bituminous type of coal), peat, petroleum (as crude oil), and natural gas. There are some other minor fossil fuels (such as oil shale) but the preceding list covers the major fossil fuels. I am not really sure what you mean as sources. All fossil fuels have a similar source. They are the natural hydrocarbon remains of larger land plants for peats and coals, and microscopic marine plants (such as plankton) for petroleum. Natural gas is a by-product of the chemical and physical production of both coals and petroleum. If you are interested in more in-depth descriptions of fossil fuels, I suggest a good general introductory college level geology text book. There are also many numerous more advanced geological texts that deal in much detail with both coal and petroleum formation and occurrence. Many of these texts can be found in a good college library.
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