Changes

==Origin of Coal==

==Origin of Coal==

[[File:Figure_1_sequence_coalification.JPG|200px|thumb|right|Figure 1 Sequence Coalification. Adopted from Carlson<ref>Carlson et al. 2008. ''Physical Geology: Earth Revealed''. New York: The McGraw-Hill Companies.</ref>]]  

[[File:Figure_1_sequence_coalification.JPG|200px|thumb|right|{{figure number1|}}Sequence Coalification. Adopted from Carlson<ref>Carlson, D., and C. Plummer, 2008, Physical geology: Earth revealed: New York, McGraw-Hill, 672 p.</ref>]]  

Coal is sedimentary rock which rich organic material that compaction with coalification process. Coal construct in environment with low oxygen content, such as swamp or bogs. Coal easily known because has black colour. Furthermore, if saw under microschope will be seen remain plant that not fully decay, such as leaves and root.

Coal is a [[sedimentary]] rock with rich organic material that compacts in the coalification process. Coal is constructed in an environment with low oxygen content, such as swamps or bogs. Coal is easily known by its black color. Furthermore, if seen under a microscope it is apparent that it is the remains of  plants that are not fully decayed, such as leaves and roots.

Initially coal formation construct when acumulation plant remains with an-oxic condition, so plant can not decaying. The environment that poor with oxygen is swamp. Instead, the plants are attacked by bacteria that partly decompose th organic material and liberate oxygen and hydrogen. When that elemen come out, the percentage of carbon increase. Bacteria cannot fully decompose organic material because they are destroyed by acids liberated from plants.<ref>Lutgens et al. 2012. ''Essential of Geology''. USA: Pearson Prentice Hall</ref>

Initially, coal forms when it accumulates plant remains with anoxic conditions, so plant cannot decay. Instead, the plants are attacked by bacteria that partly decomposes the organic material and liberates oxygen and hydrogen. When those elements come out, the percentage of carbon increases. Bacteria cannot fully decompose organic material because they are destroyed by acids liberated from plants<ref>Lutgens, F. K., E. J. Tarbuck, and D. G., 2012, Essentials of Geology: Upper Saddle River, New Jersey, Pearson Prentice Hall, 592 p.</ref>

Plant remains acumulation built a peat which plant material easily known. Then peat slowly change to lignite (brown coal), which is early stage of coal formation. Because burial condition, it make pressure and temperature increase. This increases make chemical reaction, this reaction making coal losing water and gas and increasing carbon concentration. Lignite then become bituminus coal which have higher carbon concentration. If pressure and temperature increase coal bituminus become antracite, black coal with higest carbon concentration.  

Plant remains acumulation built a peat which plant material easily known. Then peat slowly change to lignite (brown coal), which is early stage of coal formation. Because burial condition, it make pressure and temperature increase. This increases make chemical reaction, this reaction making coal losing water and gas and increasing carbon concentration. Lignite then become bituminus coal which have higher carbon concentration. If pressure and temperature increase coal bituminus become antracite, black coal with higest carbon concentration.