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Coal- 2

Coal Formation

Coal is very old. The formation of coal spans the geologic ages and is still being formed today, just very slowly. Below, a coal slab shows the footprints of a dinosaur (the footprints where made during the peat stage but were preserved during the coalification process).

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Noted paleontologist (not really) Dr. Mathews takes you on a tour (Text Version) of some of the EMS museum's prized coal-related fossil specimens (for those with a reasonably high-speed connection, and the stamina to bear a 4 minute (Quicktime) movie.

JPM

Dr. Jonathan Mathews has contributed to this material on this subject. He is currently an Assistant Professor in the Department of Energy and Mineral Engineering at Penn State University. He is an active member of the Fuel Chemistry Division of ACS.

His research interests are in Coal, carbon, carbon molecular sieves, sequestration of carbon dioxide. Complex structural elucidation Molecular modeling. Diffusion of molecules in zeolites, asphaltenes structures, coal structure (maceral structure). Structural influences on processing behaviors. Char and coke structure, molecular modeling.

 

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Source: Joe Nickel, The Skepticism
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Amber is the fossil of tree resin released by plants to heal wounds and protect the tree from insects. Often the insects are captured by the resin and preserved. Here amber contains ants. This specimen is young, probably about 1 million years old. Does Jurassic Park ring a bell? Image copyright of Skeptical Inquirer magazine and the Committee for the Scientific Investigation of Claims of the Paranormal.

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Not all coal is black. Low rank coals, such as lignite, can be brown in color. The majority of coal is black (we think it is because coal mines are dirty) but there are also examples of Peacock coal such as the one shown here. A thin mineral coating is the cause of the "oil-like" shimmer.

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Source: JPM

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Source: JPM
I took this image 100 feet from the entrance to a coal mine. Very little has changed in 320 million years or so. Inside the mine I could see fossils of the same size and morphology.
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Source: JPM
There exists a multitude of evidence to indicate that coal was derived from plant life (mostly). Here the inner bark of a Sigillaria tree might look like bird tracks but it is a bark pattern. The shale contains coal-filled markings. We also can fine coalified trees, leaf fossils and biomarkers (chemicals we identify with life-organic chemistry) within the coal.
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The organic matter that falls or is washed into the swamp will be protected from the usual decay process because of the low oxygen concentration in the water. Decay will occur in the less bio-resistant material, leaving behind the bio-resistant organic material. Eventually this material will form peat. With burial and the "cooking" of the earth (as you get deeper, it gets warmer) for geological time periods low rank coals will form. The process of coal formation might repeat itself and so layers of coal and rock are present in many locations within the US.

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US Coal Supplies & Ages

Coal is well dispersed throughout the continental United States. We have about 25% of the World reserve of coal, and all the various ranks of coal.

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Source: USGS
As the image shows, much of the coal was deposited during just a couple of the early geologic ages. Note that the anthracite region and the bituminous region within PA are both the same age. Remember that the mountain formation (producing high temperatures and pressures) was needed to form anthracite. Younger coal seams may overlie the seams in these coal-fields but they will be much smaller reserves (less coal).

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Source: MW
A brief geological overview of the organic foundations for coal - i.e. the earth's ancient flora and fauna.