Damberger, Heinz H. Illinois State Geological Survey, Champaign, Illinois.
Last reviewed:March 2019
Show previous versions
- Coal seams
- Coal rank
- Links to Primary Literature
- Additional Readings
A brown to black combustible carbonaceous sedimentary rock that is mined and used primarily as a fuel. Coal originated by accumulation and subsequent physical and chemical alteration of plant material over about 300 million years, and contains at least 50 percent by weight carbon. The plant debris accumulated in various wet environments, commonly called peat swamps, where dead plants were largely protected from decay by a high water table and oxygen-deficient water. The accumulating spongy, water-saturated, plant-derived organic material, known as peat, is the precursor of coal. Over time, many changes of the original vegetable matter were brought about by bacteria, fungi, and chemical agents. The process progressively transformed peat into lignite or brown coal (lowest quality and carbon content), subbituminous coal, bituminous coal, and anthracite (highest quality and carbon content, Fig. 1). This progression is known as the coalification series. Increasingly deeper burial under hundreds to thousands of meters of younger sediments is required to advance coalification to the bituminous coal and anthracite stages. The pressure exerted by the weight of the overlying sediment and the heat that increases with depth, as well as the length of exposure to them, determine the degree of coalification reached. See also: Coal paleobotany; Coal mining; Fossil fuel; Kerogen; Lignite; Peat; Sedimentary rocks
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information