How did geologic events play a role in forming coal?

Check these sites.

http://www.classzone.com/books/earth_science/terc/content/visualizations/es0701/es0701page01.cfm?chapter_no=visualization

http://lincoln.midcoast.com/~wps/3ripley9899/spinning.htm

http://www.ket.org/Trips/Coal/AGSMM/agsmmhow.html

Geologic events have indeed played a significant role in forming coal. To understand this process, we need to look at the geological history of coal formation.

1. Formation of Peat: Coal is primarily formed from ancient plants and organic matter, primarily trees, ferns, and other vegetation that lived millions of years ago in swampy or marshy environments. These environments provided the ideal conditions for the accumulation of organic material.

2. Geological Deposition: Over millions of years, plant material gradually accumulated in these swampy areas, forming layers of woody debris, leaves, and other organic matter. This layer is called peat, which represents the earliest stage of coal formation.

3. Sedimentary Processes: Over time, additional sediment, such as sand, mud, and silt, gets deposited on top of the peat layer. These sediments exert immense pressure due to their weight, causing compaction of the underlying peat. This pressure gradually removes water and promotes further concentration of organic matter.

4. Burial and Heat: As more and more sediment accumulates over the peat, it gets buried deeper and deeper in the Earth's crust. The increasing burial depth exposes the peat to high temperatures and pressures due to the heat generated by Earth's internal processes. This combination of high temperatures and pressure over extended periods is known as diagenesis.

5. Coalification: Diagenesis triggers a series of chemical changes within the peat, transforming it into coal through a process called coalification. The heat drives off volatile components, such as water, methane, and other gases, leaving behind a concentrated carbon-rich material - coal.

6. Types of Coal: The degree of coalification determines the type of coal produced. Lignite, the least carbon-rich and youngest type of coal, forms at shallow depths. Bituminous coal, which is more carbon-rich, forms at greater burial depths. And finally, anthracite, the most carbon-rich and oldest type of coal, forms at significant depths under intense heat and pressure.

In summary, geologic events such as sediment deposition, burial, heat, and pressure over millions of years have played a crucial role in the formation of coal from ancient plant material. These processes transform the initial organic matter into the various types of coal we find and use today.