About 300 million years ago, the earth had dense forests in low-lying wetland areas. Due to natural processes such as flooding, these forests were buried under the soil. As more and more soil deposited over them, they were compressed. The temperature also rose as they sank deeper and deeper. For the process to continue, the plant matter was protected from biodegradation and oxidization, usually by mud or acidic water. This trapped the carbon in immense peat bogs that were eventually covered and deeply buried by sediments. Under high pressure and high temperature, dead vegetation was slowly converted to coal. As coal contains mainly carbon, the conversion of dead vegetation into coal is called carbonization.
The wide, shallow seas of the Carboniferous era provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants — this coal is presumed to have originated from residues of algae.
Read more about this topic: Coal
Other articles related to "formation":
... This provisional government with Dupont de l'Eure as its president, consisted of Lamartine for foreign affairs, Crémieux for justice, Ledru-Rollin for the interior, Carnot for public instruction, Goudchaux for finance, Arago for the navy, and Burdeau for war ... Garnier-Pagès was mayor of Paris ...
... Formation of the primitive streak is reliant upon nodal signaling within the cells contributing to the primitive streak and BMP4 signaling from the extraembryonic tissue ... bilateral symmetry, determine the site of gastrulation and initiate germ layer formation ... process of gastrulation and germ layer formation ...
... The standard Gibbs free energy of formation of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of that substance from its component elements ... gas, graphite, etc.) have 0 standard Gibbs free energy change of formation, as there is no change involved ...
... As formed the Mobile Division was made up of the 1st and 2nd Light Armoured Brigades, the 1st Tank Brigade, artillery, engineers and signals ... Its paper strength was 620 armoured fighting vehicles, but seven eighths of these were reconnaissance vehicles, and of those some were being simulated by trucks ...
Famous quotes containing the word formation:
“I want you to consider this distinction as you go forward in life. Being male is not enough; being a man is a right to be earned and an honor to be cherished. I cannot tell you how to earn that right or deserve that honor. . . but I can tell you that the formation of your manhood must be a conscious act governed by the highest vision of the man you want to be.”
—Kent Nerburn (20th century)
“Out of my discomforts, which were small enough, grew one thing for which I have all my life been gratefulthe formation of fixed habits of work.”
—Elizabeth Stuart Phelps (18441911)
“... the mass migrations now habitual in our nation are disastrous to the family and to the formation of individual character. It is impossible to create a stable society if something like a third of our people are constantly moving about. We cannot grow fine human beings, any more than we can grow fine trees, if they are constantly torn up by the roots and transplanted ...”
—Agnes E. Meyer (18871970)